[v6,3/4] vfio: vfio-pci device assignment driver

This adds the core of the QEMU VFIO-based PCI device assignment driver.
To make use of this driver, enable CONFIG_VFIO, CONFIG_VFIO_IOMMU_TYPE1,
and CONFIG_VFIO_PCI in your host Linux kernel config.  Load the vfio-pci
module.  To assign device 0000:05:00.0 to a guest, do the following:

for dev in $(ls /sys/bus/pci/devices/0000:05:00.0/iommu_group/devices); do
    vendor=$(cat /sys/bus/pci/devices/$dev/vendor)
    device=$(cat /sys/bus/pci/devices/$dev/device)
    if [ -e /sys/bus/pci/devices/$dev/driver ]; then
        echo $dev > /sys/bus/pci/devices/$dev/driver/unbind
    fi
    echo $vendor $device > /sys/bus/pci/drivers/vfio-pci/new_id
done

See Documentation/vfio.txt in the Linux kernel tree for further
description of IOMMU groups and VFIO.

Then launch qemu including the option:

-device vfio-pci,host=0000:05:00.0

Legacy PCI interrupts (INTx) currently makes use of a kludge where we
trap BAR accesses and assume the access is in response to an interrupt,
therefore de-asserting and unmasking the interrupt.  It's not quite as
targetted as using the EOI for this, but it's self contained and seems
to work across all architectures.  The side-effect is a significant
performance slow-down for device in INTx mode.  Some devices, like
graphics cards, don't really use their interrupt, so this can be turned
off with the x-intx=off option, which disables INTx alltogether.  This
should be considered an experimental option until we refine this code.
Both MSI and MSI-X are supported and avoid these issues.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---

 hw/vfio_pci.c     | 1864 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/vfio_pci_int.h |  114 +++
 2 files changed, 1978 insertions(+)
 create mode 100644 hw/vfio_pci.c
 create mode 100644 hw/vfio_pci_int.h

This:

    struct vfio_iommu_type1_dma_map map = {
        .argsz = sizeof(map),
        .flags = VFIO_DMA_MAP_FLAG_READ,
        .vaddr = (__u64)vaddr,
        .iova = iova,
        .size = size,
    };

(around line 771)

breaks in my environment. I am in a crosschain environment on a i386
buildin PPC (32bit) binaries. I am using emdebian utilities, and have
been cross building qemu for months now.

The configure:
PKG_CONFIG_PATH=/usr/powerpc-linux-gnu/lib/pkgconfig ./configure
--prefix=/mnt/DATA/DARCO/alien --enable-debug-tcg --enable-debug
--enable-trace-backend=simple --disable-strip --disable-kvm
--enable-profiler --target-list=i386-softmmu --static --disable-curl
--cross-prefix=powerpc-linux-gnu- --with-coroutine=sigaltstack

The build:
make clean && make -j && make install

The error:
/mnt/DATA/DARCO/qemu-git/hw/vfio_pci.c: In function 'vfio_dma_map':
/mnt/DATA/DARCO/qemu-git/hw/vfio_pci.c:771: error: cast from pointer
to integer of different size

On Wed, Sep 26, 2012 at 5:19 PM, Alex Williamson
<alex.williamson@redhat.com> wrote:
> This adds the core of the QEMU VFIO-based PCI device assignment driver.
> To make use of this driver, enable CONFIG_VFIO, CONFIG_VFIO_IOMMU_TYPE1,
> and CONFIG_VFIO_PCI in your host Linux kernel config.  Load the vfio-pci
> module.  To assign device 0000:05:00.0 to a guest, do the following:
>
> for dev in $(ls /sys/bus/pci/devices/0000:05:00.0/iommu_group/devices); do
>     vendor=$(cat /sys/bus/pci/devices/$dev/vendor)
>     device=$(cat /sys/bus/pci/devices/$dev/device)
>     if [ -e /sys/bus/pci/devices/$dev/driver ]; then
>         echo $dev > /sys/bus/pci/devices/$dev/driver/unbind
>     fi
>     echo $vendor $device > /sys/bus/pci/drivers/vfio-pci/new_id
> done
>
> See Documentation/vfio.txt in the Linux kernel tree for further
> description of IOMMU groups and VFIO.
>
> Then launch qemu including the option:
>
> -device vfio-pci,host=0000:05:00.0
>
> Legacy PCI interrupts (INTx) currently makes use of a kludge where we
> trap BAR accesses and assume the access is in response to an interrupt,
> therefore de-asserting and unmasking the interrupt.  It's not quite as
> targetted as using the EOI for this, but it's self contained and seems
> to work across all architectures.  The side-effect is a significant
> performance slow-down for device in INTx mode.  Some devices, like
> graphics cards, don't really use their interrupt, so this can be turned
> off with the x-intx=off option, which disables INTx alltogether.  This
> should be considered an experimental option until we refine this code.
> Both MSI and MSI-X are supported and avoid these issues.
>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
>  hw/vfio_pci.c     | 1864 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/vfio_pci_int.h |  114 +++
>  2 files changed, 1978 insertions(+)
>  create mode 100644 hw/vfio_pci.c
>  create mode 100644 hw/vfio_pci_int.h
>
> diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c
> new file mode 100644
> index 0000000..a24558a
> --- /dev/null
> +++ b/hw/vfio_pci.c
> @@ -0,0 +1,1864 @@
> +/*
> + * vfio based device assignment support
> + *
> + * Copyright Red Hat, Inc. 2012
> + *
> + * Authors:
> + *  Alex Williamson <alex.williamson@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + * Based on qemu-kvm device-assignment:
> + *  Adapted for KVM by Qumranet.
> + *  Copyright (c) 2007, Neocleus, Alex Novik (alex@neocleus.com)
> + *  Copyright (c) 2007, Neocleus, Guy Zana (guy@neocleus.com)
> + *  Copyright (C) 2008, Qumranet, Amit Shah (amit.shah@qumranet.com)
> + *  Copyright (C) 2008, Red Hat, Amit Shah (amit.shah@redhat.com)
> + *  Copyright (C) 2008, IBM, Muli Ben-Yehuda (muli@il.ibm.com)
> + */
> +
> +#include <dirent.h>
> +#include <unistd.h>
> +#include <sys/ioctl.h>
> +#include <sys/mman.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <linux/vfio.h>
> +
> +#include "config.h"
> +#include "event_notifier.h"
> +#include "exec-memory.h"
> +#include "kvm.h"
> +#include "memory.h"
> +#include "msi.h"
> +#include "msix.h"
> +#include "qemu-error.h"
> +#include "range.h"
> +#include "vfio_pci_int.h"
> +
> +/* #define DEBUG_VFIO */
> +#ifdef DEBUG_VFIO
> +#define DPRINTF(fmt, ...) \
> +    do { fprintf(stderr, "vfio: " fmt, ## __VA_ARGS__); } while (0)
> +#else
> +#define DPRINTF(fmt, ...) \
> +    do { } while (0)
> +#endif
> +
> +#define MSIX_CAP_LENGTH 12
> +
> +static QLIST_HEAD(, VFIOContainer)
> +    container_list = QLIST_HEAD_INITIALIZER(container_list);
> +
> +static QLIST_HEAD(, VFIOGroup)
> +    group_list = QLIST_HEAD_INITIALIZER(group_list);
> +
> +static void vfio_disable_interrupts(VFIODevice *vdev);
> +static uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len);
> +static void vfio_mmap_set_enabled(VFIODevice *vdev, bool enabled);
> +
> +/*
> + * Common VFIO interrupt disable
> + */
> +static void vfio_disable_irqindex(VFIODevice *vdev, int index)
> +{
> +    struct vfio_irq_set irq_set = {
> +        .argsz = sizeof(irq_set),
> +        .flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER,
> +        .index = index,
> +        .start = 0,
> +        .count = 0,
> +    };
> +
> +    ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
> +
> +    vdev->interrupt = VFIO_INT_NONE;
> +}
> +
> +/*
> + * INTx
> + */
> +static void vfio_unmask_intx(VFIODevice *vdev)
> +{
> +    struct vfio_irq_set irq_set = {
> +        .argsz = sizeof(irq_set),
> +        .flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_UNMASK,
> +        .index = VFIO_PCI_INTX_IRQ_INDEX,
> +        .start = 0,
> +        .count = 1,
> +    };
> +
> +    ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
> +}
> +
> +static void vfio_intx_interrupt(void *opaque)
> +{
> +    VFIODevice *vdev = opaque;
> +
> +    if (!event_notifier_test_and_clear(&vdev->intx.interrupt)) {
> +        return;
> +    }
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x) Pin %c\n", __func__, vdev->host.domain,
> +            vdev->host.bus, vdev->host.slot, vdev->host.function,
> +            'A' + vdev->intx.pin);
> +
> +    vdev->intx.pending = true;
> +    qemu_set_irq(vdev->pdev.irq[vdev->intx.pin], 1);
> +}
> +
> +static void vfio_eoi(VFIODevice *vdev)
> +{
> +    if (!vdev->intx.pending) {
> +        return;
> +    }
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x) EOI\n", __func__, vdev->host.domain,
> +            vdev->host.bus, vdev->host.slot, vdev->host.function);
> +
> +    vdev->intx.pending = false;
> +    qemu_set_irq(vdev->pdev.irq[vdev->intx.pin], 0);
> +    vfio_unmask_intx(vdev);
> +}
> +
> +typedef struct QEMU_PACKED VFIOIRQSetFD {
> +    struct vfio_irq_set irq_set;
> +    int32_t fd;
> +} VFIOIRQSetFD;

I'm now getting this error from Clang:

/src/qemu/hw/vfio_pci.c:126:25: error: field 'irq_set' with variable
sized type 'struct vfio_irq_set' not at the end of a struct or class
is a GNU extension [-Werror,-Wgnu]
    struct vfio_irq_set irq_set;

Does the kernel really use the fd field, isn't it implicit from the
ioctl fd or are they different?

> +
> +static int vfio_enable_intx(VFIODevice *vdev)
> +{
> +    VFIOIRQSetFD irq_set_fd = {
> +        .irq_set = {
> +            .argsz = sizeof(irq_set_fd),
> +            .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
> +            .index = VFIO_PCI_INTX_IRQ_INDEX,
> +            .start = 0,
> +            .count = 1,
> +        },

Here the field is not even initialized.

> +    };
> +    uint8_t pin = vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1);
> +    int ret;
> +
> +    if (vdev->intx.disabled || !pin) {
> +        return 0;
> +    }
> +
> +    vfio_disable_interrupts(vdev);
> +
> +    vdev->intx.pin = pin - 1; /* Pin A (1) -> irq[0] */
> +    ret = event_notifier_init(&vdev->intx.interrupt, 0);
> +    if (ret) {
> +        error_report("vfio: Error: event_notifier_init failed\n");
> +        return ret;
> +    }
> +
> +    irq_set_fd.fd = event_notifier_get_fd(&vdev->intx.interrupt);
> +    qemu_set_fd_handler(irq_set_fd.fd, vfio_intx_interrupt, NULL, vdev);
> +
> +    if (ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set_fd)) {
> +        error_report("vfio: Error: Failed to setup INTx fd: %m\n");
> +        return -errno;
> +    }
> +
> +    /*
> +     * Disable mmaps so we can trap on BAR accesses.  We interpret any
> +     * access as a response to an interrupt and unmask the physical
> +     * device.  The device will re-assert if the interrupt is still
> +     * pending.  We'll likely retrigger on the host multiple times per
> +     * guest interrupt, but without EOI notification it's better than
> +     * nothing.  Acceleration paths through KVM will avoid this.
> +     */
> +    vfio_mmap_set_enabled(vdev, false);
> +
> +    vdev->interrupt = VFIO_INT_INTx;
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x)\n", __func__, vdev->host.domain,
> +            vdev->host.bus, vdev->host.slot, vdev->host.function);
> +
> +    return 0;
> +}
> +
> +static void vfio_disable_intx(VFIODevice *vdev)
> +{
> +    int fd;
> +
> +    vfio_disable_irqindex(vdev, VFIO_PCI_INTX_IRQ_INDEX);
> +    vdev->intx.pending = false;
> +    qemu_set_irq(vdev->pdev.irq[vdev->intx.pin], 0);
> +    vfio_mmap_set_enabled(vdev, true);
> +
> +    fd = event_notifier_get_fd(&vdev->intx.interrupt);
> +    qemu_set_fd_handler(fd, NULL, NULL, vdev);
> +    event_notifier_cleanup(&vdev->intx.interrupt);
> +
> +    vdev->interrupt = VFIO_INT_NONE;
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x)\n", __func__, vdev->host.domain,
> +            vdev->host.bus, vdev->host.slot, vdev->host.function);
> +}
> +
> +/*
> + * MSI/X
> + */
> +static void vfio_msi_interrupt(void *opaque)
> +{
> +    VFIOMSIVector *vector = opaque;
> +    VFIODevice *vdev = vector->vdev;
> +    int nr = vector - vdev->msi_vectors;
> +
> +    if (!event_notifier_test_and_clear(&vector->interrupt)) {
> +        return;
> +    }
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x) vector %d\n", __func__,
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, nr);
> +
> +    if (vdev->interrupt == VFIO_INT_MSIX) {
> +        msix_notify(&vdev->pdev, nr);
> +    } else if (vdev->interrupt == VFIO_INT_MSI) {
> +        msi_notify(&vdev->pdev, nr);
> +    } else {
> +        error_report("vfio: MSI interrupt receieved, but not enabled?\n");
> +    }
> +}
> +
> +static int vfio_enable_vectors(VFIODevice *vdev, bool msix)
> +{
> +    struct vfio_irq_set *irq_set;
> +    int ret = 0, i, argsz;
> +    int32_t *fds;
> +
> +    argsz = sizeof(*irq_set) + (vdev->nr_vectors * sizeof(*fds));
> +
> +    irq_set = g_malloc0(argsz);
> +    irq_set->argsz = argsz;
> +    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
> +    irq_set->index = msix ? VFIO_PCI_MSIX_IRQ_INDEX : VFIO_PCI_MSI_IRQ_INDEX;
> +    irq_set->start = 0;
> +    irq_set->count = vdev->nr_vectors;
> +    fds = (int32_t *)&irq_set->data;
> +
> +    for (i = 0; i < vdev->nr_vectors; i++) {
> +        if (!vdev->msi_vectors[i].use) {
> +            fds[i] = -1;
> +            continue;
> +        }
> +
> +        fds[i] = event_notifier_get_fd(&vdev->msi_vectors[i].interrupt);
> +    }
> +
> +    ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
> +
> +    g_free(irq_set);
> +
> +    if (!ret) {
> +        vdev->interrupt = msix ? VFIO_INT_MSIX : VFIO_INT_MSI;
> +    }
> +
> +    return ret;
> +}
> +
> +static int vfio_msix_vector_use(PCIDevice *pdev,
> +                                unsigned int nr, MSIMessage msg)
> +{
> +    VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> +    VFIOMSIVector *vector;
> +    int ret;
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x) vector %d used\n", __func__,
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, nr);
> +
> +    if (vdev->interrupt != VFIO_INT_MSIX) {
> +        vfio_disable_interrupts(vdev);
> +    }
> +
> +    if (!vdev->msi_vectors) {
> +        vdev->msi_vectors = g_malloc0(vdev->msix->entries *
> +                                      sizeof(VFIOMSIVector));
> +    }
> +
> +    vector = &vdev->msi_vectors[nr];
> +    vector->vdev = vdev;
> +    vector->use = true;
> +
> +    msix_vector_use(pdev, nr);
> +
> +    if (event_notifier_init(&vector->interrupt, 0)) {
> +        error_report("vfio: Error: event_notifier_init failed\n");
> +    }
> +
> +    /*
> +     * Attempt to enable route through KVM irqchip,
> +     * default to userspace handling if unavailable.
> +     */
> +    vector->virq = kvm_irqchip_add_msi_route(kvm_state, msg);
> +    if (vector->virq < 0 ||
> +        kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt,
> +                                       vector->virq) < 0) {
> +        if (vector->virq >= 0) {
> +            kvm_irqchip_release_virq(kvm_state, vector->virq);
> +            vector->virq = -1;
> +        }
> +        qemu_set_fd_handler(event_notifier_get_fd(&vector->interrupt),
> +                            vfio_msi_interrupt, NULL, vector);
> +    }
> +
> +    /*
> +     * We don't want to have the host allocate all possible MSI vectors
> +     * for a device if they're not in use, so we shutdown and incrementally
> +     * increase them as needed.
> +     */
> +    if (vdev->nr_vectors < nr + 1) {
> +        int i;
> +
> +        vfio_disable_irqindex(vdev, VFIO_PCI_MSIX_IRQ_INDEX);
> +        vdev->nr_vectors = nr + 1;
> +        ret = vfio_enable_vectors(vdev, true);
> +        if (ret) {
> +            error_report("vfio: failed to enable vectors, %d\n", ret);
> +        }
> +
> +        /* We don't know if we've missed interrupts in the interim... */
> +        for (i = 0; i < vdev->msix->entries; i++) {
> +            if (vdev->msi_vectors[i].use) {
> +                msix_notify(&vdev->pdev, i);
> +            }
> +        }
> +    } else {
> +        VFIOIRQSetFD irq_set_fd = {
> +            .irq_set = {
> +                .argsz = sizeof(irq_set_fd),
> +                .flags = VFIO_IRQ_SET_DATA_EVENTFD |
> +                         VFIO_IRQ_SET_ACTION_TRIGGER,
> +                .index = VFIO_PCI_MSIX_IRQ_INDEX,
> +                .start = nr,
> +                .count = 1,
> +            },
> +            .fd = event_notifier_get_fd(&vector->interrupt),
> +        };
> +        ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set_fd);
> +        if (ret) {
> +            error_report("vfio: failed to modify vector, %d\n", ret);
> +        }
> +
> +        /*
> +         * If we were connected to the hardware PBA we could skip this,
> +         * until then, a spurious interrupt is better than starvation.
> +         */
> +        msix_notify(&vdev->pdev, nr);
> +    }
> +
> +    return 0;
> +}
> +
> +static void vfio_msix_vector_release(PCIDevice *pdev, unsigned int nr)
> +{
> +    VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> +    VFIOMSIVector *vector = &vdev->msi_vectors[nr];
> +    VFIOIRQSetFD irq_set_fd = {
> +        .irq_set = {
> +            .argsz = sizeof(irq_set_fd),
> +            .flags = VFIO_IRQ_SET_DATA_EVENTFD |
> +                     VFIO_IRQ_SET_ACTION_TRIGGER,
> +            .index = VFIO_PCI_MSIX_IRQ_INDEX,
> +            .start = nr,
> +            .count = 1,
> +        },
> +        .fd = -1,
> +    };
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x) vector %d released\n", __func__,
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, nr);
> +
> +    /*
> +     * XXX What's the right thing to do here?  This turns off the interrupt
> +     * completely, but do we really just want to switch the interrupt to
> +     * bouncing through userspace and let msix.c drop it?  Not sure.
> +     */
> +    msix_vector_unuse(pdev, nr);
> +    ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set_fd);
> +
> +    if (vector->virq < 0) {
> +        qemu_set_fd_handler(event_notifier_get_fd(&vector->interrupt),
> +                            NULL, NULL, NULL);
> +    } else {
> +        kvm_irqchip_remove_irqfd_notifier(kvm_state, &vector->interrupt,
> +                                          vector->virq);
> +        kvm_irqchip_release_virq(kvm_state, vector->virq);
> +        vector->virq = -1;
> +    }
> +
> +    event_notifier_cleanup(&vector->interrupt);
> +    vector->use = false;
> +}
> +
> +/* TODO This should move to msi.c */
> +static MSIMessage msi_get_msg(PCIDevice *pdev, unsigned int vector)
> +{
> +    uint16_t flags = pci_get_word(pdev->config + pdev->msi_cap + PCI_MSI_FLAGS);
> +    bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
> +    MSIMessage msg;
> +
> +    if (msi64bit) {
> +        msg.address = pci_get_quad(pdev->config +
> +                                   pdev->msi_cap + PCI_MSI_ADDRESS_LO);
> +    } else {
> +        msg.address = pci_get_long(pdev->config +
> +                                   pdev->msi_cap + PCI_MSI_ADDRESS_LO);
> +    }
> +
> +    msg.data = pci_get_word(pdev->config + pdev->msi_cap +
> +                            (msi64bit ? PCI_MSI_DATA_64 : PCI_MSI_DATA_32));
> +    msg.data += vector;
> +
> +    return msg;
> +}
> +
> +/* So should this */
> +static void msi_set_qsize(PCIDevice *pdev, uint8_t size)
> +{
> +    uint8_t *config = pdev->config + pdev->msi_cap;
> +    uint16_t flags;
> +
> +    flags = pci_get_word(config + PCI_MSI_FLAGS);
> +    flags = le16_to_cpu(flags);
> +    flags &= ~PCI_MSI_FLAGS_QSIZE;
> +    flags |= (size & 0x7) << 4;
> +    flags = cpu_to_le16(flags);
> +    pci_set_word(config + PCI_MSI_FLAGS, flags);
> +}
> +
> +static void vfio_enable_msi(VFIODevice *vdev)
> +{
> +    int ret, i;
> +
> +    vfio_disable_interrupts(vdev);
> +
> +    vdev->nr_vectors = msi_nr_vectors_allocated(&vdev->pdev);
> +retry:
> +    vdev->msi_vectors = g_malloc0(vdev->nr_vectors * sizeof(VFIOMSIVector));
> +
> +    for (i = 0; i < vdev->nr_vectors; i++) {
> +        MSIMessage msg;
> +        VFIOMSIVector *vector = &vdev->msi_vectors[i];
> +
> +        vector->vdev = vdev;
> +        vector->use = true;
> +
> +        if (event_notifier_init(&vector->interrupt, 0)) {
> +            error_report("vfio: Error: event_notifier_init failed\n");
> +        }
> +
> +        msg = msi_get_msg(&vdev->pdev, i);
> +
> +        /*
> +         * Attempt to enable route through KVM irqchip,
> +         * default to userspace handling if unavailable.
> +         */
> +        vector->virq = kvm_irqchip_add_msi_route(kvm_state, msg);
> +        if (vector->virq < 0 ||
> +            kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt,
> +                                           vector->virq) < 0) {
> +            qemu_set_fd_handler(event_notifier_get_fd(&vector->interrupt),
> +                                vfio_msi_interrupt, NULL, vector);
> +        }
> +    }
> +
> +    ret = vfio_enable_vectors(vdev, false);
> +    if (ret) {
> +        if (ret < 0) {
> +            error_report("vfio: Error: Failed to setup MSI fds: %m\n");
> +        } else if (ret != vdev->nr_vectors) {
> +            error_report("vfio: Error: Failed to enable %d "
> +                         "MSI vectors, retry with %d\n", vdev->nr_vectors, ret);
> +        }
> +
> +        for (i = 0; i < vdev->nr_vectors; i++) {
> +            VFIOMSIVector *vector = &vdev->msi_vectors[i];
> +            if (vector->virq >= 0) {
> +                kvm_irqchip_remove_irqfd_notifier(kvm_state, &vector->interrupt,
> +                                                  vector->virq);
> +                kvm_irqchip_release_virq(kvm_state, vector->virq);
> +                vector->virq = -1;
> +            } else {
> +                qemu_set_fd_handler(event_notifier_get_fd(&vector->interrupt),
> +                                    NULL, NULL, NULL);
> +            }
> +            event_notifier_cleanup(&vector->interrupt);
> +        }
> +
> +        g_free(vdev->msi_vectors);
> +
> +        if (ret > 0 && ret != vdev->nr_vectors) {
> +            vdev->nr_vectors = ret;
> +            goto retry;
> +        }
> +        vdev->nr_vectors = 0;
> +
> +        return;
> +    }
> +
> +    msi_set_qsize(&vdev->pdev, vdev->nr_vectors);
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x) Enabled %d MSI vectors\n", __func__,
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, vdev->nr_vectors);
> +}
> +
> +static void vfio_disable_msi_x(VFIODevice *vdev, bool msix)
> +{
> +    int i;
> +
> +    vfio_disable_irqindex(vdev, msix ? VFIO_PCI_MSIX_IRQ_INDEX :
> +                                       VFIO_PCI_MSI_IRQ_INDEX);
> +
> +    for (i = 0; i < vdev->nr_vectors; i++) {
> +        VFIOMSIVector *vector = &vdev->msi_vectors[i];
> +
> +        if (!vector->use) {
> +            continue;
> +        }
> +
> +        if (vector->virq >= 0) {
> +            kvm_irqchip_remove_irqfd_notifier(kvm_state,
> +                                              &vector->interrupt, vector->virq);
> +            kvm_irqchip_release_virq(kvm_state, vector->virq);
> +            vector->virq = -1;
> +        } else {
> +            qemu_set_fd_handler(event_notifier_get_fd(&vector->interrupt),
> +                                NULL, NULL, NULL);
> +        }
> +
> +        if (msix) {
> +            msix_vector_unuse(&vdev->pdev, i);
> +        }
> +
> +        event_notifier_cleanup(&vector->interrupt);
> +    }
> +
> +    g_free(vdev->msi_vectors);
> +    vdev->msi_vectors = NULL;
> +    vdev->nr_vectors = 0;
> +
> +    if (!msix) {
> +        msi_set_qsize(&vdev->pdev, 0); /* Actually still means 1 vector */
> +    }
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x, msi%s)\n", __func__,
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, msix ? "x" : "");
> +
> +    vfio_enable_intx(vdev);
> +}
> +
> +/*
> + * IO Port/MMIO - Beware of the endians, VFIO is always little endian
> + */
> +static void vfio_bar_write(void *opaque, target_phys_addr_t addr,
> +                           uint64_t data, unsigned size)
> +{
> +    VFIOBAR *bar = opaque;
> +    union {
> +        uint8_t byte;
> +        uint16_t word;
> +        uint32_t dword;
> +        uint64_t qword;
> +    } buf;
> +
> +    switch (size) {
> +    case 1:
> +        buf.byte = data;
> +        break;
> +    case 2:
> +        buf.word = cpu_to_le16(data);
> +        break;
> +    case 4:
> +        buf.dword = cpu_to_le32(data);
> +        break;
> +    default:
> +        hw_error("vfio: unsupported write size, %d bytes\n", size);
> +        break;
> +    }
> +
> +    if (pwrite(bar->fd, &buf, size, bar->fd_offset + addr) != size) {
> +        error_report("%s(,0x%"TARGET_PRIxPHYS", 0x%"PRIx64", %d) failed: %m\n",
> +                     __func__, addr, data, size);
> +    }
> +
> +    DPRINTF("%s(BAR%d+0x%"TARGET_PRIxPHYS", 0x%"PRIx64", %d)\n",
> +            __func__, bar->nr, addr, data, size);
> +
> +    /*
> +     * A read or write to a BAR always signals an INTx EOI.  This will
> +     * do nothing if not pending (including not in INTx mode).  We assume
> +     * that a BAR access is in response to an interrupt and that BAR
> +     * accesses will service the interrupt.  Unfortunately, we don't know
> +     * which access will service the interrupt, so we're potentially
> +     * getting quite a few host interrupts per guest interrupt.
> +     */
> +    vfio_eoi(DO_UPCAST(VFIODevice, bars[bar->nr], bar));
> +}
> +
> +static uint64_t vfio_bar_read(void *opaque,
> +                              target_phys_addr_t addr, unsigned size)
> +{
> +    VFIOBAR *bar = opaque;
> +    union {
> +        uint8_t byte;
> +        uint16_t word;
> +        uint32_t dword;
> +        uint64_t qword;
> +    } buf;
> +    uint64_t data = 0;
> +
> +    if (pread(bar->fd, &buf, size, bar->fd_offset + addr) != size) {
> +        error_report("%s(,0x%"TARGET_PRIxPHYS", %d) failed: %m\n",
> +                     __func__, addr, size);
> +        return (uint64_t)-1;
> +    }
> +
> +    switch (size) {
> +    case 1:
> +        data = buf.byte;
> +        break;
> +    case 2:
> +        data = le16_to_cpu(buf.word);
> +        break;
> +    case 4:
> +        data = le32_to_cpu(buf.dword);
> +        break;
> +    default:
> +        hw_error("vfio: unsupported read size, %d bytes\n", size);
> +        break;
> +    }
> +
> +    DPRINTF("%s(BAR%d+0x%"TARGET_PRIxPHYS", %d) = 0x%"PRIx64"\n",
> +            __func__, bar->nr, addr, size, data);
> +
> +    /* Same as write above */
> +    vfio_eoi(DO_UPCAST(VFIODevice, bars[bar->nr], bar));
> +
> +    return data;
> +}
> +
> +static const MemoryRegionOps vfio_bar_ops = {
> +    .read = vfio_bar_read,
> +    .write = vfio_bar_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +};
> +
> +/*
> + * PCI config space
> + */
> +static uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len)
> +{
> +    VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> +    uint32_t val = 0;
> +
> +    /*
> +     * We only need QEMU PCI config support for the ROM BAR, the MSI and MSIX
> +     * capabilities, and the multifunction bit below.  We let VFIO handle
> +     * virtualizing everything else.  Performance is not a concern here.
> +     */
> +    if (ranges_overlap(addr, len, PCI_ROM_ADDRESS, 4) ||
> +        (pdev->cap_present & QEMU_PCI_CAP_MSIX &&
> +         ranges_overlap(addr, len, pdev->msix_cap, MSIX_CAP_LENGTH)) ||
> +        (pdev->cap_present & QEMU_PCI_CAP_MSI &&
> +         ranges_overlap(addr, len, pdev->msi_cap, vdev->msi_cap_size))) {
> +
> +        val = pci_default_read_config(pdev, addr, len);
> +    } else {
> +        if (pread(vdev->fd, &val, len, vdev->config_offset + addr) != len) {
> +            error_report("%s(%04x:%02x:%02x.%x, 0x%x, 0x%x) failed: %m\n",
> +                         __func__, vdev->host.domain, vdev->host.bus,
> +                         vdev->host.slot, vdev->host.function, addr, len);
> +            return -errno;
> +        }
> +        val = le32_to_cpu(val);
> +    }
> +
> +    /* Multifunction bit is virualized in QEMU */
> +    if (unlikely(ranges_overlap(addr, len, PCI_HEADER_TYPE, 1))) {
> +        uint32_t mask = PCI_HEADER_TYPE_MULTI_FUNCTION;
> +
> +        if (len == 4) {
> +            mask <<= 16;
> +        }
> +
> +        if (pdev->cap_present & QEMU_PCI_CAP_MULTIFUNCTION) {
> +            val |= mask;
> +        } else {
> +            val &= ~mask;
> +        }
> +    }
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x, @0x%x, len=0x%x) %x\n", __func__,
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, addr, len, val);
> +
> +    return val;
> +}
> +
> +static void vfio_pci_write_config(PCIDevice *pdev, uint32_t addr,
> +                                  uint32_t val, int len)
> +{
> +    VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> +    uint32_t val_le = cpu_to_le32(val);
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x, @0x%x, 0x%x, len=0x%x)\n", __func__,
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, addr, val, len);
> +
> +    /* Write everything to VFIO, let it filter out what we can't write */
> +    if (pwrite(vdev->fd, &val_le, len, vdev->config_offset + addr) != len) {
> +        error_report("%s(%04x:%02x:%02x.%x, 0x%x, 0x%x, 0x%x) failed: %m\n",
> +                     __func__, vdev->host.domain, vdev->host.bus,
> +                     vdev->host.slot, vdev->host.function, addr, val, len);
> +    }
> +
> +    /* Write standard header bits to emulation */
> +    if (addr < PCI_CONFIG_HEADER_SIZE) {
> +        pci_default_write_config(pdev, addr, val, len);
> +        return;
> +    }
> +
> +    /* MSI/MSI-X Enabling/Disabling */
> +    if (pdev->cap_present & QEMU_PCI_CAP_MSI &&
> +        ranges_overlap(addr, len, pdev->msi_cap, vdev->msi_cap_size)) {
> +        int is_enabled, was_enabled = msi_enabled(pdev);
> +
> +        pci_default_write_config(pdev, addr, val, len);
> +
> +        is_enabled = msi_enabled(pdev);
> +
> +        if (!was_enabled && is_enabled) {
> +            vfio_enable_msi(vdev);
> +        } else if (was_enabled && !is_enabled) {
> +            vfio_disable_msi_x(vdev, false);
> +        }
> +    }
> +
> +    if (pdev->cap_present & QEMU_PCI_CAP_MSIX &&
> +        ranges_overlap(addr, len, pdev->msix_cap, MSIX_CAP_LENGTH)) {
> +        int is_enabled, was_enabled = msix_enabled(pdev);
> +
> +        pci_default_write_config(pdev, addr, val, len);
> +
> +        is_enabled = msix_enabled(pdev);
> +
> +        if (!was_enabled && is_enabled) {
> +            /* vfio_msix_vector_use handles this automatically */
> +        } else if (was_enabled && !is_enabled) {
> +            vfio_disable_msi_x(vdev, true);
> +        }
> +    }
> +}
> +
> +/*
> + * DMA - Mapping and unmapping for the "type1" IOMMU interface used on x86
> + */
> +static int vfio_dma_map(VFIOContainer *container, target_phys_addr_t iova,
> +                        ram_addr_t size, void *vaddr, bool readonly)
> +{
> +    struct vfio_iommu_type1_dma_map map = {
> +        .argsz = sizeof(map),
> +        .flags = VFIO_DMA_MAP_FLAG_READ,
> +        .vaddr = (__u64)vaddr,
> +        .iova = iova,
> +        .size = size,
> +    };
> +
> +    if (!readonly) {
> +        map.flags |= VFIO_DMA_MAP_FLAG_WRITE;
> +    }
> +
> +    if (ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map)) {
> +        DPRINTF("VFIO_MAP_DMA: %d\n", -errno);
> +        return -errno;
> +    }
> +
> +    return 0;
> +}
> +
> +static int vfio_dma_unmap(VFIOContainer *container,
> +                          target_phys_addr_t iova, ram_addr_t size)
> +{
> +    struct vfio_iommu_type1_dma_unmap unmap = {
> +        .argsz = sizeof(unmap),
> +        .flags = 0,
> +        .iova = iova,
> +        .size = size,
> +    };
> +
> +    if (ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
> +        DPRINTF("VFIO_UNMAP_DMA: %d\n", -errno);
> +        return -errno;
> +    }
> +
> +    return 0;
> +}
> +
> +static void vfio_listener_dummy1(MemoryListener *listener)
> +{
> +    /* We don't do batching (begin/commit) or care about logging */
> +}
> +
> +static void vfio_listener_dummy2(MemoryListener *listener,
> +                                 MemoryRegionSection *section)
> +{
> +    /* We don't do logging or care about nops */
> +}
> +
> +static void vfio_listener_dummy3(MemoryListener *listener,
> +                                 MemoryRegionSection *section,
> +                                 bool match_data, uint64_t data,
> +                                 EventNotifier *e)
> +{
> +    /* We don't care about eventfds */
> +}
> +
> +static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> +{
> +    return !memory_region_is_ram(section->mr);
> +}
> +
> +static void vfio_listener_region_add(MemoryListener *listener,
> +                                     MemoryRegionSection *section)
> +{
> +    VFIOContainer *container = container_of(listener, VFIOContainer,
> +                                            iommu_data.listener);
> +    target_phys_addr_t iova, end;
> +    void *vaddr;
> +    int ret;
> +
> +    if (vfio_listener_skipped_section(section)) {
> +        DPRINTF("vfio: SKIPPING region_add %"TARGET_PRIxPHYS" - %"PRIx64"\n",
> +                section->offset_within_address_space,
> +                section->offset_within_address_space + section->size - 1);
> +        return;
> +    }
> +
> +    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
> +                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
> +        error_report("%s received unaligned region\n", __func__);
> +        return;
> +    }
> +
> +    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
> +    end = (section->offset_within_address_space + section->size) &
> +          TARGET_PAGE_MASK;
> +
> +    if (iova >= end) {
> +        return;
> +    }
> +
> +    vaddr = memory_region_get_ram_ptr(section->mr) +
> +            section->offset_within_region +
> +            (iova - section->offset_within_address_space);
> +
> +    DPRINTF("vfio: region_add %"TARGET_PRIxPHYS" - %"TARGET_PRIxPHYS" [%p]\n",
> +            iova, end - 1, vaddr);
> +
> +    ret = vfio_dma_map(container, iova, end - iova, vaddr, section->readonly);
> +    if (ret) {
> +        error_report("vfio_dma_map(%p, 0x%"TARGET_PRIxPHYS", "
> +                     "0x%"TARGET_PRIxPHYS", %p) = %d (%m)\n",
> +                     container, iova, end - iova, vaddr, ret);
> +    }
> +}
> +
> +static void vfio_listener_region_del(MemoryListener *listener,
> +                                     MemoryRegionSection *section)
> +{
> +    VFIOContainer *container = container_of(listener, VFIOContainer,
> +                                            iommu_data.listener);
> +    target_phys_addr_t iova, end;
> +    int ret;
> +
> +    if (vfio_listener_skipped_section(section)) {
> +        DPRINTF("vfio: SKIPPING region_del %"TARGET_PRIxPHYS" - %"PRIx64"\n",
> +                section->offset_within_address_space,
> +                section->offset_within_address_space + section->size - 1);
> +        return;
> +    }
> +
> +    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
> +                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
> +        error_report("%s received unaligned region\n", __func__);
> +        return;
> +    }
> +
> +    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
> +    end = (section->offset_within_address_space + section->size) &
> +          TARGET_PAGE_MASK;
> +
> +    if (iova >= end) {
> +        return;
> +    }
> +
> +    DPRINTF("vfio: region_del %"TARGET_PRIxPHYS" - %"TARGET_PRIxPHYS"\n",
> +            iova, end - 1);
> +
> +    ret = vfio_dma_unmap(container, iova, end - iova);
> +    if (ret) {
> +        error_report("vfio_dma_unmap(%p, 0x%"TARGET_PRIxPHYS", "
> +                     "0x%"TARGET_PRIxPHYS") = %d (%m)\n",
> +                     container, iova, end - iova, ret);
> +    }
> +}
> +
> +static MemoryListener vfio_memory_listener = {
> +    .begin = vfio_listener_dummy1,
> +    .commit = vfio_listener_dummy1,
> +    .region_add = vfio_listener_region_add,
> +    .region_del = vfio_listener_region_del,
> +    .region_nop = vfio_listener_dummy2,
> +    .log_start = vfio_listener_dummy2,
> +    .log_stop = vfio_listener_dummy2,
> +    .log_sync = vfio_listener_dummy2,
> +    .log_global_start = vfio_listener_dummy1,
> +    .log_global_stop = vfio_listener_dummy1,
> +    .eventfd_add = vfio_listener_dummy3,
> +    .eventfd_del = vfio_listener_dummy3,
> +};
> +
> +static void vfio_listener_release(VFIOContainer *container)
> +{
> +    memory_listener_unregister(&container->iommu_data.listener);
> +}
> +
> +/*
> + * Interrupt setup
> + */
> +static void vfio_disable_interrupts(VFIODevice *vdev)
> +{
> +    switch (vdev->interrupt) {
> +    case VFIO_INT_INTx:
> +        vfio_disable_intx(vdev);
> +        break;
> +    case VFIO_INT_MSI:
> +        vfio_disable_msi_x(vdev, false);
> +        break;
> +    case VFIO_INT_MSIX:
> +        vfio_disable_msi_x(vdev, true);
> +        break;
> +    }
> +}
> +
> +static int vfio_setup_msi(VFIODevice *vdev, int pos)
> +{
> +    uint16_t ctrl;
> +    bool msi_64bit, msi_maskbit;
> +    int ret, entries;
> +
> +    /*
> +     * TODO: don't peek into msi_supported, let msi_init fail and
> +     * check for ENOTSUP
> +     */
> +    if (!msi_supported) {
> +        return 0;
> +    }
> +
> +    if (pread(vdev->fd, &ctrl, sizeof(ctrl),
> +              vdev->config_offset + pos + PCI_CAP_FLAGS) != sizeof(ctrl)) {
> +        return -errno;
> +    }
> +    ctrl = le16_to_cpu(ctrl);
> +
> +    msi_64bit = !!(ctrl & PCI_MSI_FLAGS_64BIT);
> +    msi_maskbit = !!(ctrl & PCI_MSI_FLAGS_MASKBIT);
> +    entries = 1 << ((ctrl & PCI_MSI_FLAGS_QMASK) >> 1);
> +
> +    DPRINTF("%04x:%02x:%02x.%x PCI MSI CAP @0x%x\n", vdev->host.domain,
> +            vdev->host.bus, vdev->host.slot, vdev->host.function, pos);
> +
> +    ret = msi_init(&vdev->pdev, pos, entries, msi_64bit, msi_maskbit);
> +    if (ret < 0) {
> +        error_report("vfio: msi_init failed\n");
> +        return ret;
> +    }
> +    vdev->msi_cap_size = 0xa + (msi_maskbit ? 0xa : 0) + (msi_64bit ? 0x4 : 0);
> +
> +    return 0;
> +}
> +
> +/*
> + * We don't have any control over how pci_add_capability() inserts
> + * capabilities into the chain.  In order to setup MSI-X we need a
> + * MemoryRegion for the BAR.  In order to setup the BAR and not
> + * attempt to mmap the MSI-X table area, which VFIO won't allow, we
> + * need to first look for where the MSI-X table lives.  So we
> + * unfortunately split MSI-X setup across two functions.
> + */
> +static int vfio_early_setup_msix(VFIODevice *vdev)
> +{
> +    uint8_t pos;
> +    uint16_t ctrl;
> +    uint32_t table, pba;
> +
> +    pos = pci_find_capability(&vdev->pdev, PCI_CAP_ID_MSIX);
> +    if (!pos) {
> +        return 0;
> +    }
> +
> +    if (pread(vdev->fd, &ctrl, sizeof(ctrl),
> +              vdev->config_offset + pos + PCI_CAP_FLAGS) != sizeof(ctrl)) {
> +        return -errno;
> +    }
> +
> +    if (pread(vdev->fd, &table, sizeof(table),
> +              vdev->config_offset + pos + PCI_MSIX_TABLE) != sizeof(table)) {
> +        return -errno;
> +    }
> +
> +    if (pread(vdev->fd, &pba, sizeof(pba),
> +              vdev->config_offset + pos + PCI_MSIX_PBA) != sizeof(pba)) {
> +        return -errno;
> +    }
> +
> +    ctrl = le16_to_cpu(ctrl);
> +    table = le32_to_cpu(table);
> +    pba = le32_to_cpu(pba);
> +
> +    vdev->msix = g_malloc0(sizeof(*(vdev->msix)));
> +    vdev->msix->table_bar = table & PCI_MSIX_FLAGS_BIRMASK;
> +    vdev->msix->table_offset = table & ~PCI_MSIX_FLAGS_BIRMASK;
> +    vdev->msix->pba_bar = pba & PCI_MSIX_FLAGS_BIRMASK;
> +    vdev->msix->pba_offset = pba & ~PCI_MSIX_FLAGS_BIRMASK;
> +    vdev->msix->entries = (ctrl & PCI_MSIX_FLAGS_QSIZE) + 1;
> +
> +    DPRINTF("%04x:%02x:%02x.%x "
> +            "PCI MSI-X CAP @0x%x, BAR %d, offset 0x%x, entries %d\n",
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function, pos, vdev->msix->table_bar,
> +            vdev->msix->table_offset, vdev->msix->entries);
> +
> +    return 0;
> +}
> +
> +static int vfio_setup_msix(VFIODevice *vdev, int pos)
> +{
> +    int ret;
> +
> +    /*
> +     * TODO: don't peek into msi_supported, let msix_init fail and
> +     * check for ENOTSUP
> +     */
> +    if (!msi_supported) {
> +        return 0;
> +    }
> +
> +    ret = msix_init(&vdev->pdev, vdev->msix->entries,
> +                    &vdev->bars[vdev->msix->table_bar].mem,
> +                    vdev->msix->table_bar, vdev->msix->table_offset,
> +                    &vdev->bars[vdev->msix->pba_bar].mem,
> +                    vdev->msix->pba_bar, vdev->msix->pba_offset, pos);
> +    if (ret < 0) {
> +        error_report("vfio: msix_init failed\n");
> +        return ret;
> +    }
> +
> +    ret = msix_set_vector_notifiers(&vdev->pdev, vfio_msix_vector_use,
> +                                    vfio_msix_vector_release);
> +    if (ret) {
> +        error_report("vfio: msix_set_vector_notifiers failed %d\n", ret);
> +        msix_uninit(&vdev->pdev, &vdev->bars[vdev->msix->table_bar].mem,
> +                    &vdev->bars[vdev->msix->pba_bar].mem);
> +        return ret;
> +    }
> +
> +    return 0;
> +}
> +
> +static void vfio_teardown_msi(VFIODevice *vdev)
> +{
> +    msi_uninit(&vdev->pdev);
> +
> +    if (vdev->msix) {
> +        /* FIXME: Why can't unset just silently do nothing?? */
> +        if (vdev->pdev.msix_vector_use_notifier &&
> +            vdev->pdev.msix_vector_release_notifier) {
> +            msix_unset_vector_notifiers(&vdev->pdev);
> +        }
> +
> +        msix_uninit(&vdev->pdev, &vdev->bars[vdev->msix->table_bar].mem,
> +                    &vdev->bars[vdev->msix->pba_bar].mem);
> +    }
> +}
> +
> +/*
> + * Resource setup
> + */
> +static void vfio_mmap_set_enabled(VFIODevice *vdev, bool enabled)
> +{
> +    int i;
> +
> +    for (i = 0; i < PCI_ROM_SLOT; i++) {
> +        VFIOBAR *bar = &vdev->bars[i];
> +
> +        if (!bar->size) {
> +            continue;
> +        }
> +
> +        memory_region_set_enabled(&bar->mmap_mem, enabled);
> +        if (vdev->msix && vdev->msix->table_bar == i) {
> +            memory_region_set_enabled(&vdev->msix->mmap_mem, enabled);
> +        }
> +    }
> +}
> +
> +static void vfio_unmap_bar(VFIODevice *vdev, int nr)
> +{
> +    VFIOBAR *bar = &vdev->bars[nr];
> +
> +    if (!bar->size) {
> +        return;
> +    }
> +
> +    memory_region_del_subregion(&bar->mem, &bar->mmap_mem);
> +    munmap(bar->mmap, memory_region_size(&bar->mmap_mem));
> +
> +    if (vdev->msix && vdev->msix->table_bar == nr) {
> +        memory_region_del_subregion(&bar->mem, &vdev->msix->mmap_mem);
> +        munmap(vdev->msix->mmap, memory_region_size(&vdev->msix->mmap_mem));
> +    }
> +
> +    memory_region_destroy(&bar->mem);
> +}
> +
> +static int vfio_mmap_bar(VFIOBAR *bar, MemoryRegion *mem, MemoryRegion *submem,
> +                         void **map, size_t size, off_t offset,
> +                         const char *name)
> +{
> +    int ret = 0;
> +
> +    if (size && bar->flags & VFIO_REGION_INFO_FLAG_MMAP) {
> +        int prot = 0;
> +
> +        if (bar->flags & VFIO_REGION_INFO_FLAG_READ) {
> +            prot |= PROT_READ;
> +        }
> +
> +        if (bar->flags & VFIO_REGION_INFO_FLAG_WRITE) {
> +            prot |= PROT_WRITE;
> +        }
> +
> +        *map = mmap(NULL, size, prot, MAP_SHARED,
> +                    bar->fd, bar->fd_offset + offset);
> +        if (*map == MAP_FAILED) {
> +            *map = NULL;
> +            ret = -errno;
> +            goto empty_region;
> +        }
> +
> +        memory_region_init_ram_ptr(submem, name, size, *map);
> +    } else {
> +empty_region:
> +        /* Create a zero sized sub-region to make cleanup easy. */
> +        memory_region_init(submem, name, 0);
> +    }
> +
> +    memory_region_add_subregion(mem, offset, submem);
> +
> +    return ret;
> +}
> +
> +static void vfio_map_bar(VFIODevice *vdev, int nr)
> +{
> +    VFIOBAR *bar = &vdev->bars[nr];
> +    unsigned size = bar->size;
> +    char name[64];
> +    uint32_t pci_bar;
> +    uint8_t type;
> +    int ret;
> +
> +    /* Skip both unimplemented BARs and the upper half of 64bit BARS. */
> +    if (!size) {
> +        return;
> +    }
> +
> +    snprintf(name, sizeof(name), "VFIO %04x:%02x:%02x.%x BAR %d",
> +             vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +             vdev->host.function, nr);
> +
> +    /* Determine what type of BAR this is for registration */
> +    ret = pread(vdev->fd, &pci_bar, sizeof(pci_bar),
> +                vdev->config_offset + PCI_BASE_ADDRESS_0 + (4 * nr));
> +    if (ret != sizeof(pci_bar)) {
> +        error_report("vfio: Failed to read BAR %d (%m)\n", nr);
> +        return;
> +    }
> +
> +    pci_bar = le32_to_cpu(pci_bar);
> +    type = pci_bar & (pci_bar & PCI_BASE_ADDRESS_SPACE_IO ?
> +           ~PCI_BASE_ADDRESS_IO_MASK : ~PCI_BASE_ADDRESS_MEM_MASK);
> +
> +    /* A "slow" read/write mapping underlies all BARs */
> +    memory_region_init_io(&bar->mem, &vfio_bar_ops, bar, name, size);
> +    pci_register_bar(&vdev->pdev, nr, type, &bar->mem);
> +
> +    /*
> +     * We can't mmap areas overlapping the MSIX vector table, so we
> +     * potentially insert a direct-mapped subregion before and after it.
> +     */
> +    if (vdev->msix && vdev->msix->table_bar == nr) {
> +        size = vdev->msix->table_offset & TARGET_PAGE_MASK;
> +    }
> +
> +    strncat(name, " mmap", sizeof(name) - strlen(name) - 1);
> +    if (vfio_mmap_bar(bar, &bar->mem,
> +                      &bar->mmap_mem, &bar->mmap, size, 0, name)) {
> +        error_report("%s unsupported. Performance may be slow\n", name);
> +    }
> +
> +    if (vdev->msix && vdev->msix->table_bar == nr) {
> +        unsigned start;
> +
> +        start = TARGET_PAGE_ALIGN(vdev->msix->table_offset +
> +                                  (vdev->msix->entries * PCI_MSIX_ENTRY_SIZE));
> +
> +        size = start < bar->size ? bar->size - start : 0;
> +        strncat(name, " msix-hi", sizeof(name) - strlen(name) - 1);
> +        /* VFIOMSIXInfo contains another MemoryRegion for this mapping */
> +        if (vfio_mmap_bar(bar, &bar->mem, &vdev->msix->mmap_mem,
> +                          &vdev->msix->mmap, size, start, name)) {
> +            error_report("%s unsupported. Performance may be slow\n", name);
> +        }
> +    }
> +}
> +
> +static void vfio_map_bars(VFIODevice *vdev)
> +{
> +    int i;
> +
> +    for (i = 0; i < PCI_ROM_SLOT; i++) {
> +        vfio_map_bar(vdev, i);
> +    }
> +}
> +
> +static void vfio_unmap_bars(VFIODevice *vdev)
> +{
> +    int i;
> +
> +    for (i = 0; i < PCI_ROM_SLOT; i++) {
> +        vfio_unmap_bar(vdev, i);
> +    }
> +}
> +
> +/*
> + * General setup
> + */
> +static uint8_t vfio_std_cap_max_size(PCIDevice *pdev, uint8_t pos)
> +{
> +    uint8_t tmp, next = 0xff;
> +
> +    for (tmp = pdev->config[PCI_CAPABILITY_LIST]; tmp;
> +         tmp = pdev->config[tmp + 1]) {
> +        if (tmp > pos && tmp < next) {
> +            next = tmp;
> +        }
> +    }
> +
> +    return next - pos;
> +}
> +
> +static int vfio_add_std_cap(VFIODevice *vdev, uint8_t pos)
> +{
> +    PCIDevice *pdev = &vdev->pdev;
> +    uint8_t cap_id, next, size;
> +    int ret;
> +
> +    cap_id = pdev->config[pos];
> +    next = pdev->config[pos + 1];
> +
> +    /*
> +     * If it becomes important to configure capabilities to their actual
> +     * size, use this as the default when it's something we don't recognize.
> +     * Since QEMU doesn't actually handle many of the config accesses,
> +     * exact size doesn't seem worthwhile.
> +     */
> +    size = vfio_std_cap_max_size(pdev, pos);
> +
> +    /*
> +     * pci_add_capability always inserts the new capability at the head
> +     * of the chain.  Therefore to end up with a chain that matches the
> +     * physical device, we insert from the end by making this recursive.
> +     * This is also why we pre-caclulate size above as cached config space
> +     * will be changed as we unwind the stack.
> +     */
> +    if (next) {
> +        ret = vfio_add_std_cap(vdev, next);
> +        if (ret) {
> +            return ret;
> +        }
> +    } else {
> +        pdev->config[PCI_CAPABILITY_LIST] = 0; /* Begin the rebuild */
> +    }
> +
> +    switch (cap_id) {
> +    case PCI_CAP_ID_MSI:
> +        ret = vfio_setup_msi(vdev, pos);
> +        break;
> +    case PCI_CAP_ID_MSIX:
> +        ret = vfio_setup_msix(vdev, pos);
> +        break;
> +    default:
> +        ret = pci_add_capability(pdev, cap_id, pos, size);
> +        break;
> +    }
> +
> +    if (ret < 0) {
> +        error_report("vfio: %04x:%02x:%02x.%x Error adding PCI capability "
> +                     "0x%x[0x%x]@0x%x: %d\n", vdev->host.domain,
> +                     vdev->host.bus, vdev->host.slot, vdev->host.function,
> +                     cap_id, size, pos, ret);
> +        return ret;
> +    }
> +
> +    return 0;
> +}
> +
> +static int vfio_add_capabilities(VFIODevice *vdev)
> +{
> +    PCIDevice *pdev = &vdev->pdev;
> +
> +    if (!(pdev->config[PCI_STATUS] & PCI_STATUS_CAP_LIST) ||
> +        !pdev->config[PCI_CAPABILITY_LIST]) {
> +        return 0; /* Nothing to add */
> +    }
> +
> +    return vfio_add_std_cap(vdev, pdev->config[PCI_CAPABILITY_LIST]);
> +}
> +
> +static int vfio_load_rom(VFIODevice *vdev)
> +{
> +    uint64_t size = vdev->rom_size;
> +    char name[32];
> +    off_t off = 0, voff = vdev->rom_offset;
> +    ssize_t bytes;
> +    void *ptr;
> +
> +    /* If loading ROM from file, pci handles it */
> +    if (vdev->pdev.romfile || !vdev->pdev.rom_bar || !size) {
> +        return 0;
> +    }
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x)\n", __func__, vdev->host.domain,
> +            vdev->host.bus, vdev->host.slot, vdev->host.function);
> +
> +    snprintf(name, sizeof(name), "vfio[%04x:%02x:%02x.%x].rom",
> +             vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +             vdev->host.function);
> +    memory_region_init_ram(&vdev->pdev.rom, name, size);
> +    ptr = memory_region_get_ram_ptr(&vdev->pdev.rom);
> +    memset(ptr, 0xff, size);
> +
> +    while (size) {
> +        bytes = pread(vdev->fd, ptr + off, size, voff + off);
> +        if (bytes == 0) {
> +            break; /* expect that we could get back less than the ROM BAR */
> +        } else if (bytes > 0) {
> +            off += bytes;
> +            size -= bytes;
> +        } else {
> +            if (errno == EINTR || errno == EAGAIN) {
> +                continue;
> +            }
> +            error_report("vfio: Error reading device ROM: %m\n");
> +            memory_region_destroy(&vdev->pdev.rom);
> +            return -errno;
> +        }
> +    }
> +
> +    pci_register_bar(&vdev->pdev, PCI_ROM_SLOT, 0, &vdev->pdev.rom);
> +    vdev->pdev.has_rom = true;
> +    return 0;
> +}
> +
> +static int vfio_connect_container(VFIOGroup *group)
> +{
> +    VFIOContainer *container;
> +    int ret, fd;
> +
> +    if (group->container) {
> +        return 0;
> +    }
> +
> +    QLIST_FOREACH(container, &container_list, next) {
> +        if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) {
> +            group->container = container;
> +            QLIST_INSERT_HEAD(&container->group_list, group, container_next);
> +            return 0;
> +        }
> +    }
> +
> +    fd = qemu_open("/dev/vfio/vfio", O_RDWR);
> +    if (fd < 0) {
> +        error_report("vfio: failed to open /dev/vfio/vfio: %m\n");
> +        return -errno;
> +    }
> +
> +    ret = ioctl(fd, VFIO_GET_API_VERSION);
> +    if (ret != VFIO_API_VERSION) {
> +        error_report("vfio: supported vfio version: %d, "
> +                     "reported version: %d\n", VFIO_API_VERSION, ret);
> +        close(fd);
> +        return -EINVAL;
> +    }
> +
> +    container = g_malloc0(sizeof(*container));
> +    container->fd = fd;
> +
> +    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
> +        ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
> +        if (ret) {
> +            error_report("vfio: failed to set group container: %m\n");
> +            g_free(container);
> +            close(fd);
> +            return -errno;
> +        }
> +
> +        ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU);
> +        if (ret) {
> +            error_report("vfio: failed to set iommu for container: %m\n");
> +            g_free(container);
> +            close(fd);
> +            return -errno;
> +        }
> +
> +        container->iommu_data.listener = vfio_memory_listener;
> +        container->iommu_data.release = vfio_listener_release;
> +
> +        memory_listener_register(&container->iommu_data.listener,
> +                                 get_system_memory());
> +    } else {
> +        error_report("vfio: No available IOMMU models\n");
> +        g_free(container);
> +        close(fd);
> +        return -EINVAL;
> +    }
> +
> +    QLIST_INIT(&container->group_list);
> +    QLIST_INSERT_HEAD(&container_list, container, next);
> +
> +    group->container = container;
> +    QLIST_INSERT_HEAD(&container->group_list, group, container_next);
> +
> +    return 0;
> +}
> +
> +static void vfio_disconnect_container(VFIOGroup *group)
> +{
> +    VFIOContainer *container = group->container;
> +
> +    if (ioctl(group->fd, VFIO_GROUP_UNSET_CONTAINER, &container->fd)) {
> +        error_report("vfio: error disconnecting group %d from container\n",
> +                     group->groupid);
> +    }
> +
> +    QLIST_REMOVE(group, container_next);
> +    group->container = NULL;
> +
> +    if (QLIST_EMPTY(&container->group_list)) {
> +        if (container->iommu_data.release) {
> +            container->iommu_data.release(container);
> +        }
> +        QLIST_REMOVE(container, next);
> +        DPRINTF("vfio_disconnect_container: close container->fd\n");
> +        close(container->fd);
> +        g_free(container);
> +    }
> +}
> +
> +static VFIOGroup *vfio_get_group(int groupid)
> +{
> +    VFIOGroup *group;
> +    char path[32];
> +    struct vfio_group_status status = { .argsz = sizeof(status) };
> +
> +    QLIST_FOREACH(group, &group_list, next) {
> +        if (group->groupid == groupid) {
> +            return group;
> +        }
> +    }
> +
> +    group = g_malloc0(sizeof(*group));
> +
> +    snprintf(path, sizeof(path), "/dev/vfio/%d", groupid);
> +    group->fd = qemu_open(path, O_RDWR);
> +    if (group->fd < 0) {
> +        error_report("vfio: error opening %s: %m\n", path);
> +        g_free(group);
> +        return NULL;
> +    }
> +
> +    if (ioctl(group->fd, VFIO_GROUP_GET_STATUS, &status)) {
> +        error_report("vfio: error getting group status: %m\n");
> +        close(group->fd);
> +        g_free(group);
> +        return NULL;
> +    }
> +
> +    if (!(status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
> +        error_report("vfio: error, group %d is not viable, please ensure "
> +                     "all devices within the iommu_group are bound to their "
> +                     "vfio bus driver.\n", groupid);
> +        close(group->fd);
> +        g_free(group);
> +        return NULL;
> +    }
> +
> +    group->groupid = groupid;
> +    QLIST_INIT(&group->device_list);
> +
> +    if (vfio_connect_container(group)) {
> +        error_report("vfio: failed to setup container for group %d\n", groupid);
> +        close(group->fd);
> +        g_free(group);
> +        return NULL;
> +    }
> +
> +    QLIST_INSERT_HEAD(&group_list, group, next);
> +
> +    return group;
> +}
> +
> +static void vfio_put_group(VFIOGroup *group)
> +{
> +    if (!QLIST_EMPTY(&group->device_list)) {
> +        return;
> +    }
> +
> +    vfio_disconnect_container(group);
> +    QLIST_REMOVE(group, next);
> +    DPRINTF("vfio_put_group: close group->fd\n");
> +    close(group->fd);
> +    g_free(group);
> +}
> +
> +static int vfio_get_device(VFIOGroup *group, const char *name, VFIODevice *vdev)
> +{
> +    struct vfio_device_info dev_info = { .argsz = sizeof(dev_info) };
> +    struct vfio_region_info reg_info = { .argsz = sizeof(reg_info) };
> +    int ret, i;
> +
> +    ret = ioctl(group->fd, VFIO_GROUP_GET_DEVICE_FD, name);
> +    if (ret < 0) {
> +        error_report("vfio: error getting device %s from group %d: %m\n",
> +                     name, group->groupid);
> +        error_report("Verify all devices in group %d are bound to vfio-pci "
> +                     "or pci-stub and not already in use\n", group->groupid);
> +        return ret;
> +    }
> +
> +    vdev->fd = ret;
> +    vdev->group = group;
> +    QLIST_INSERT_HEAD(&group->device_list, vdev, next);
> +
> +    /* Sanity check device */
> +    ret = ioctl(vdev->fd, VFIO_DEVICE_GET_INFO, &dev_info);
> +    if (ret) {
> +        error_report("vfio: error getting device info: %m\n");
> +        goto error;
> +    }
> +
> +    DPRINTF("Device %s flags: %u, regions: %u, irgs: %u\n", name,
> +            dev_info.flags, dev_info.num_regions, dev_info.num_irqs);
> +
> +    if (!(dev_info.flags & VFIO_DEVICE_FLAGS_PCI)) {
> +        error_report("vfio: Um, this isn't a PCI device\n");
> +        goto error;
> +    }
> +
> +    vdev->reset_works = !!(dev_info.flags & VFIO_DEVICE_FLAGS_RESET);
> +    if (!vdev->reset_works) {
> +        error_report("Warning, device %s does not support reset\n", name);
> +    }
> +
> +    if (dev_info.num_regions != VFIO_PCI_NUM_REGIONS) {
> +        error_report("vfio: unexpected number of io regions %u\n",
> +                     dev_info.num_regions);
> +        goto error;
> +    }
> +
> +    if (dev_info.num_irqs != VFIO_PCI_NUM_IRQS) {
> +        error_report("vfio: unexpected number of irqs %u\n", dev_info.num_irqs);
> +        goto error;
> +    }
> +
> +    for (i = VFIO_PCI_BAR0_REGION_INDEX; i < VFIO_PCI_ROM_REGION_INDEX; i++) {
> +        reg_info.index = i;
> +
> +        ret = ioctl(vdev->fd, VFIO_DEVICE_GET_REGION_INFO, &reg_info);
> +        if (ret) {
> +            error_report("vfio: Error getting region %d info: %m\n", i);
> +            goto error;
> +        }
> +
> +        DPRINTF("Device %s region %d:\n", name, i);
> +        DPRINTF("  size: 0x%lx, offset: 0x%lx, flags: 0x%lx\n",
> +                (unsigned long)reg_info.size, (unsigned long)reg_info.offset,
> +                (unsigned long)reg_info.flags);
> +
> +        vdev->bars[i].flags = reg_info.flags;
> +        vdev->bars[i].size = reg_info.size;
> +        vdev->bars[i].fd_offset = reg_info.offset;
> +        vdev->bars[i].fd = vdev->fd;
> +        vdev->bars[i].nr = i;
> +    }
> +
> +    reg_info.index = VFIO_PCI_ROM_REGION_INDEX;
> +
> +    ret = ioctl(vdev->fd, VFIO_DEVICE_GET_REGION_INFO, &reg_info);
> +    if (ret) {
> +        error_report("vfio: Error getting ROM info: %m\n");
> +        goto error;
> +    }
> +
> +    DPRINTF("Device %s ROM:\n", name);
> +    DPRINTF("  size: 0x%lx, offset: 0x%lx, flags: 0x%lx\n",
> +            (unsigned long)reg_info.size, (unsigned long)reg_info.offset,
> +            (unsigned long)reg_info.flags);
> +
> +    vdev->rom_size = reg_info.size;
> +    vdev->rom_offset = reg_info.offset;
> +
> +    reg_info.index = VFIO_PCI_CONFIG_REGION_INDEX;
> +
> +    ret = ioctl(vdev->fd, VFIO_DEVICE_GET_REGION_INFO, &reg_info);
> +    if (ret) {
> +        error_report("vfio: Error getting config info: %m\n");
> +        goto error;
> +    }
> +
> +    DPRINTF("Device %s config:\n", name);
> +    DPRINTF("  size: 0x%lx, offset: 0x%lx, flags: 0x%lx\n",
> +            (unsigned long)reg_info.size, (unsigned long)reg_info.offset,
> +            (unsigned long)reg_info.flags);
> +
> +    vdev->config_size = reg_info.size;
> +    vdev->config_offset = reg_info.offset;
> +
> +error:
> +    if (ret) {
> +        QLIST_REMOVE(vdev, next);
> +        vdev->group = NULL;
> +        close(vdev->fd);
> +    }
> +    return ret;
> +}
> +
> +static void vfio_put_device(VFIODevice *vdev)
> +{
> +    QLIST_REMOVE(vdev, next);
> +    vdev->group = NULL;
> +    DPRINTF("vfio_put_device: close vdev->fd\n");
> +    close(vdev->fd);
> +    if (vdev->msix) {
> +        g_free(vdev->msix);
> +        vdev->msix = NULL;
> +    }
> +}
> +
> +static int vfio_initfn(PCIDevice *pdev)
> +{
> +    VFIODevice *pvdev, *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> +    VFIOGroup *group;
> +    char path[PATH_MAX], iommu_group_path[PATH_MAX], *group_name;
> +    ssize_t len;
> +    struct stat st;
> +    int groupid;
> +    int ret;
> +
> +    /* Check that the host device exists */
> +    snprintf(path, sizeof(path),
> +             "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/",
> +             vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +             vdev->host.function);
> +    if (stat(path, &st) < 0) {
> +        error_report("vfio: error: no such host device: %s\n", path);
> +        return -errno;
> +    }
> +
> +    strncat(path, "iommu_group", sizeof(path) - strlen(path) - 1);
> +
> +    len = readlink(path, iommu_group_path, PATH_MAX);
> +    if (len <= 0) {
> +        error_report("vfio: error no iommu_group for device\n");
> +        return -errno;
> +    }
> +
> +    iommu_group_path[len] = 0;
> +    group_name = basename(iommu_group_path);
> +
> +    if (sscanf(group_name, "%d", &groupid) != 1) {
> +        error_report("vfio: error reading %s: %m\n", path);
> +        return -errno;
> +    }
> +
> +    DPRINTF("%s(%04x:%02x:%02x.%x) group %d\n", __func__, vdev->host.domain,
> +            vdev->host.bus, vdev->host.slot, vdev->host.function, groupid);
> +
> +    group = vfio_get_group(groupid);
> +    if (!group) {
> +        error_report("vfio: failed to get group %d\n", groupid);
> +        return -ENOENT;
> +    }
> +
> +    snprintf(path, sizeof(path), "%04x:%02x:%02x.%01x",
> +            vdev->host.domain, vdev->host.bus, vdev->host.slot,
> +            vdev->host.function);
> +
> +    QLIST_FOREACH(pvdev, &group->device_list, next) {
> +        if (pvdev->host.domain == vdev->host.domain &&
> +            pvdev->host.bus == vdev->host.bus &&
> +            pvdev->host.slot == vdev->host.slot &&
> +            pvdev->host.function == vdev->host.function) {
> +
> +            error_report("vfio: error: device %s is already attached\n", path);
> +            vfio_put_group(group);
> +            return -EBUSY;
> +        }
> +    }
> +
> +    ret = vfio_get_device(group, path, vdev);
> +    if (ret) {
> +        error_report("vfio: failed to get device %s\n", path);
> +        vfio_put_group(group);
> +        return ret;
> +    }
> +
> +    /* Get a copy of config space */
> +    ret = pread(vdev->fd, vdev->pdev.config,
> +                MIN(pci_config_size(&vdev->pdev), vdev->config_size),
> +                vdev->config_offset);
> +    if (ret < (int)MIN(pci_config_size(&vdev->pdev), vdev->config_size)) {
> +        ret = ret < 0 ? -errno : -EFAULT;
> +        error_report("vfio: Failed to read device config space\n");
> +        goto out_put;
> +    }
> +
> +    /*
> +     * Clear host resource mapping info.  If we choose not to register a
> +     * BAR, such as might be the case with the option ROM, we can get
> +     * confusing, unwritable, residual addresses from the host here.
> +     */
> +    memset(&vdev->pdev.config[PCI_BASE_ADDRESS_0], 0, 24);
> +    memset(&vdev->pdev.config[PCI_ROM_ADDRESS], 0, 4);
> +
> +    vfio_load_rom(vdev);
> +
> +    ret = vfio_early_setup_msix(vdev);
> +    if (ret) {
> +        goto out_put;
> +    }
> +
> +    vfio_map_bars(vdev);
> +
> +    ret = vfio_add_capabilities(vdev);
> +    if (ret) {
> +        goto out_teardown;
> +    }
> +
> +    if (vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1)) {
> +        if (vdev->intx.intx && strcmp(vdev->intx.intx, "off")) {
> +            error_report("vfio: Unknown option x-intx=%s, "
> +                         "valid options: \"off\".\n", vdev->intx.intx);
> +            ret = -EINVAL;
> +            goto out_teardown;
> +        }
> +
> +        if (vdev->intx.intx && !strcmp(vdev->intx.intx, "off")) {
> +            vdev->intx.disabled = true;
> +        }
> +
> +        ret = vfio_enable_intx(vdev);
> +        if (ret) {
> +            goto out_teardown;
> +        }
> +    }
> +
> +    return 0;
> +
> +out_teardown:
> +    pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
> +    vfio_teardown_msi(vdev);
> +    vfio_unmap_bars(vdev);
> +out_put:
> +    vfio_put_device(vdev);
> +    vfio_put_group(group);
> +    return ret;
> +}
> +
> +static void vfio_exitfn(PCIDevice *pdev)
> +{
> +    VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> +    VFIOGroup *group = vdev->group;
> +
> +    pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
> +    vfio_disable_interrupts(vdev);
> +    vfio_teardown_msi(vdev);
> +    vfio_unmap_bars(vdev);
> +    vfio_put_device(vdev);
> +    vfio_put_group(group);
> +}
> +
> +static void vfio_pci_reset(DeviceState *dev)
> +{
> +    PCIDevice *pdev = DO_UPCAST(PCIDevice, qdev, dev);
> +    VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
> +
> +    if (!vdev->reset_works) {
> +        return;
> +    }
> +
> +    if (ioctl(vdev->fd, VFIO_DEVICE_RESET)) {
> +        error_report("vfio: Error unable to reset physical device "
> +                     "(%04x:%02x:%02x.%x): %m\n", vdev->host.domain,
> +                     vdev->host.bus, vdev->host.slot, vdev->host.function);
> +    }
> +}
> +
> +static Property vfio_pci_dev_properties[] = {
> +    DEFINE_PROP_PCI_HOST_DEVADDR("host", VFIODevice, host),
> +    DEFINE_PROP_STRING("x-intx", VFIODevice, intx.intx),
> +    /*
> +     * TODO - support passed fds... is this necessary?
> +     * DEFINE_PROP_STRING("vfiofd", VFIODevice, vfiofd_name),
> +     * DEFINE_PROP_STRING("vfiogroupfd, VFIODevice, vfiogroupfd_name),
> +     */
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +
> +static void vfio_pci_dev_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    PCIDeviceClass *pdc = PCI_DEVICE_CLASS(klass);
> +
> +    dc->reset = vfio_pci_reset;
> +    dc->props = vfio_pci_dev_properties;
> +    pdc->init = vfio_initfn;
> +    pdc->exit = vfio_exitfn;
> +    pdc->config_read = vfio_pci_read_config;
> +    pdc->config_write = vfio_pci_write_config;
> +}
> +
> +static const TypeInfo vfio_pci_dev_info = {
> +    .name = "vfio-pci",
> +    .parent = TYPE_PCI_DEVICE,
> +    .instance_size = sizeof(VFIODevice),
> +    .class_init = vfio_pci_dev_class_init,
> +};
> +
> +static void register_vfio_pci_dev_type(void)
> +{
> +    type_register_static(&vfio_pci_dev_info);
> +}
> +
> +type_init(register_vfio_pci_dev_type)
> diff --git a/hw/vfio_pci_int.h b/hw/vfio_pci_int.h
> new file mode 100644
> index 0000000..3812d8d
> --- /dev/null
> +++ b/hw/vfio_pci_int.h
> @@ -0,0 +1,114 @@
> +/*
> + * vfio based device assignment support
> + *
> + * Copyright Red Hat, Inc. 2012
> + *
> + * Authors:
> + *  Alex Williamson <alex.williamson@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + */
> +
> +#ifndef HW_VFIO_PCI_INT_H
> +#define HW_VFIO_PCI_INT_H
> +
> +#include "qemu-common.h"
> +#include "qemu-queue.h"
> +#include "pci.h"
> +#include "event_notifier.h"
> +
> +typedef struct VFIOBAR {
> +    off_t fd_offset; /* offset of BAR within device fd */
> +    int fd; /* device fd, allows us to pass VFIOBAR as opaque data */
> +    MemoryRegion mem; /* slow, read/write access */
> +    MemoryRegion mmap_mem; /* direct mapped access */
> +    void *mmap;
> +    size_t size;
> +    uint32_t flags; /* VFIO region flags (rd/wr/mmap) */
> +    uint8_t nr; /* cache the BAR number for debug */
> +} VFIOBAR;
> +
> +typedef struct VFIOINTx {
> +    bool pending; /* interrupt pending */
> +    bool kvm_accel; /* set when QEMU bypass through KVM enabled */
> +    uint8_t pin; /* which pin to pull for qemu_set_irq */
> +    EventNotifier interrupt; /* eventfd triggered on interrupt */
> +    EventNotifier unmask; /* eventfd for unmask on QEMU bypass */
> +    PCIINTxRoute route; /* routing info for QEMU bypass */
> +    bool disabled;
> +    char *intx;
> +} VFIOINTx;
> +
> +struct VFIODevice;
> +
> +typedef struct VFIOMSIVector {
> +    EventNotifier interrupt; /* eventfd triggered on interrupt */
> +    struct VFIODevice *vdev; /* back pointer to device */
> +    int virq; /* KVM irqchip route for QEMU bypass */
> +    bool use;
> +} VFIOMSIVector;
> +
> +enum {
> +    VFIO_INT_NONE = 0,
> +    VFIO_INT_INTx = 1,
> +    VFIO_INT_MSI  = 2,
> +    VFIO_INT_MSIX = 3,
> +};
> +
> +struct VFIOGroup;
> +
> +typedef struct VFIOContainer {
> +    int fd; /* /dev/vfio/vfio, empowered by the attached groups */
> +    struct {
> +        /* enable abstraction to support various iommu backends */
> +        union {
> +            MemoryListener listener; /* Used by type1 iommu */
> +        };
> +        void (*release)(struct VFIOContainer *);
> +    } iommu_data;
> +    QLIST_HEAD(, VFIOGroup) group_list;
> +    QLIST_ENTRY(VFIOContainer) next;
> +} VFIOContainer;
> +
> +/* Cache of MSI-X setup plus extra mmap and memory region for split BAR map */
> +typedef struct VFIOMSIXInfo {
> +    uint8_t table_bar;
> +    uint8_t pba_bar;
> +    uint16_t entries;
> +    uint32_t table_offset;
> +    uint32_t pba_offset;
> +    MemoryRegion mmap_mem;
> +    void *mmap;
> +} VFIOMSIXInfo;
> +
> +typedef struct VFIODevice {
> +    PCIDevice pdev;
> +    int fd;
> +    VFIOINTx intx;
> +    unsigned int config_size;
> +    off_t config_offset; /* Offset of config space region within device fd */
> +    unsigned int rom_size;
> +    off_t rom_offset; /* Offset of ROM region within device fd */
> +    int msi_cap_size;
> +    VFIOMSIVector *msi_vectors;
> +    VFIOMSIXInfo *msix;
> +    int nr_vectors; /* Number of MSI/MSIX vectors currently in use */
> +    int interrupt; /* Current interrupt type */
> +    VFIOBAR bars[PCI_NUM_REGIONS - 1]; /* No ROM */
> +    PCIHostDeviceAddress host;
> +    QLIST_ENTRY(VFIODevice) next;
> +    struct VFIOGroup *group;
> +    bool reset_works;
> +} VFIODevice;
> +
> +typedef struct VFIOGroup {
> +    int fd;
> +    int groupid;
> +    VFIOContainer *container;
> +    QLIST_HEAD(, VFIODevice) device_list;
> +    QLIST_ENTRY(VFIOGroup) next;
> +    QLIST_ENTRY(VFIOGroup) container_next;
> +} VFIOGroup;
> +
> +#endif /* HW_VFIO_PCI_INT_H */
>

On Fri, 2012-10-05 at 16:54 +0000, Blue Swirl wrote:
> On Wed, Sep 26, 2012 at 5:19 PM, Alex Williamson
> <alex.williamson@redhat.com> wrote:
> > +
> > +typedef struct QEMU_PACKED VFIOIRQSetFD {
> > +    struct vfio_irq_set irq_set;
> > +    int32_t fd;
> > +} VFIOIRQSetFD;
> 
> I'm now getting this error from Clang:
> 
> /src/qemu/hw/vfio_pci.c:126:25: error: field 'irq_set' with variable
> sized type 'struct vfio_irq_set' not at the end of a struct or class
> is a GNU extension [-Werror,-Wgnu]
>     struct vfio_irq_set irq_set;
> 
> Does the kernel really use the fd field, isn't it implicit from the
> ioctl fd or are they different?

The kernel side is defined as:

struct vfio_irq_set {
        __u32   argsz;
        __u32   flags;
        __u32   index;
        __u32   start;
        __u32   count;
        __u8    data[];
};

Where data is the start of a variable sized array.  The data type of the
array depends on the flags.  The purpose of VFIOIRQSetFD is simply to
make a data type that I don't need to dynamically allocate.  You can
find other cases for MSI and MSIX where we don't know the array size and
do malloc the whole structure.  For this interrupt type we know there's
only one entry.  If there's a better way to do this, let me know.  VFIO
is only available on Linux hosts, so I have no particular reason to
avoid GNU extensions.

> > +
> > +static int vfio_enable_intx(VFIODevice *vdev)
> > +{
> > +    VFIOIRQSetFD irq_set_fd = {
> > +        .irq_set = {
> > +            .argsz = sizeof(irq_set_fd),
> > +            .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
> > +            .index = VFIO_PCI_INTX_IRQ_INDEX,
> > +            .start = 0,
> > +            .count = 1,
> > +        },
> 
> Here the field is not even initialized.

It's initialized later...

> > +    };
> > +    uint8_t pin = vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1);
> > +    int ret;
> > +
> > +    if (vdev->intx.disabled || !pin) {
> > +        return 0;
> > +    }
> > +
> > +    vfio_disable_interrupts(vdev);
> > +
> > +    vdev->intx.pin = pin - 1; /* Pin A (1) -> irq[0] */
> > +    ret = event_notifier_init(&vdev->intx.interrupt, 0);
> > +    if (ret) {
> > +        error_report("vfio: Error: event_notifier_init failed\n");
> > +        return ret;
> > +    }
> > +
> > +    irq_set_fd.fd = event_notifier_get_fd(&vdev->intx.interrupt);

Here.

Thanks,
Alex

On Fri, Oct 5, 2012 at 5:11 PM, Alex Williamson
<alex.williamson@redhat.com> wrote:
> On Fri, 2012-10-05 at 16:54 +0000, Blue Swirl wrote:
>> On Wed, Sep 26, 2012 at 5:19 PM, Alex Williamson
>> <alex.williamson@redhat.com> wrote:
>> > +
>> > +typedef struct QEMU_PACKED VFIOIRQSetFD {
>> > +    struct vfio_irq_set irq_set;
>> > +    int32_t fd;
>> > +} VFIOIRQSetFD;
>>
>> I'm now getting this error from Clang:
>>
>> /src/qemu/hw/vfio_pci.c:126:25: error: field 'irq_set' with variable
>> sized type 'struct vfio_irq_set' not at the end of a struct or class
>> is a GNU extension [-Werror,-Wgnu]
>>     struct vfio_irq_set irq_set;
>>
>> Does the kernel really use the fd field, isn't it implicit from the
>> ioctl fd or are they different?
>
> The kernel side is defined as:
>
> struct vfio_irq_set {
>         __u32   argsz;
>         __u32   flags;
>         __u32   index;
>         __u32   start;
>         __u32   count;
>         __u8    data[];
> };

Then the kernel only expects vfio_irq_set structure, not VFIOIRQSetFD,
so you should use &irq_set_fd.irq_set instead of &irq_set_fd for the
ioctl(). Then VFIOIRQSetFD can be rearranged to have fd field first,
also QEMU_PACKED is not necessary.

>
> Where data is the start of a variable sized array.  The data type of the
> array depends on the flags.  The purpose of VFIOIRQSetFD is simply to
> make a data type that I don't need to dynamically allocate.  You can
> find other cases for MSI and MSIX where we don't know the array size and
> do malloc the whole structure.  For this interrupt type we know there's
> only one entry.  If there's a better way to do this, let me know.  VFIO
> is only available on Linux hosts, so I have no particular reason to
> avoid GNU extensions.
>
>> > +
>> > +static int vfio_enable_intx(VFIODevice *vdev)
>> > +{
>> > +    VFIOIRQSetFD irq_set_fd = {
>> > +        .irq_set = {
>> > +            .argsz = sizeof(irq_set_fd),
>> > +            .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
>> > +            .index = VFIO_PCI_INTX_IRQ_INDEX,
>> > +            .start = 0,
>> > +            .count = 1,
>> > +        },
>>
>> Here the field is not even initialized.
>
> It's initialized later...
>
>> > +    };
>> > +    uint8_t pin = vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1);
>> > +    int ret;
>> > +
>> > +    if (vdev->intx.disabled || !pin) {
>> > +        return 0;
>> > +    }
>> > +
>> > +    vfio_disable_interrupts(vdev);
>> > +
>> > +    vdev->intx.pin = pin - 1; /* Pin A (1) -> irq[0] */
>> > +    ret = event_notifier_init(&vdev->intx.interrupt, 0);
>> > +    if (ret) {
>> > +        error_report("vfio: Error: event_notifier_init failed\n");
>> > +        return ret;
>> > +    }
>> > +
>> > +    irq_set_fd.fd = event_notifier_get_fd(&vdev->intx.interrupt);
>
> Here.
>
> Thanks,
> Alex
>

On Fri, 2012-10-05 at 17:22 +0000, Blue Swirl wrote:
> On Fri, Oct 5, 2012 at 5:11 PM, Alex Williamson
> <alex.williamson@redhat.com> wrote:
> > On Fri, 2012-10-05 at 16:54 +0000, Blue Swirl wrote:
> >> On Wed, Sep 26, 2012 at 5:19 PM, Alex Williamson
> >> <alex.williamson@redhat.com> wrote:
> >> > +
> >> > +typedef struct QEMU_PACKED VFIOIRQSetFD {
> >> > +    struct vfio_irq_set irq_set;
> >> > +    int32_t fd;
> >> > +} VFIOIRQSetFD;
> >>
> >> I'm now getting this error from Clang:
> >>
> >> /src/qemu/hw/vfio_pci.c:126:25: error: field 'irq_set' with variable
> >> sized type 'struct vfio_irq_set' not at the end of a struct or class
> >> is a GNU extension [-Werror,-Wgnu]
> >>     struct vfio_irq_set irq_set;
> >>
> >> Does the kernel really use the fd field, isn't it implicit from the
> >> ioctl fd or are they different?
> >
> > The kernel side is defined as:
> >
> > struct vfio_irq_set {
> >         __u32   argsz;
> >         __u32   flags;
> >         __u32   index;
> >         __u32   start;
> >         __u32   count;
> >         __u8    data[];
> > };
> 
> Then the kernel only expects vfio_irq_set structure, not VFIOIRQSetFD,
> so you should use &irq_set_fd.irq_set instead of &irq_set_fd for the
> ioctl(). Then VFIOIRQSetFD can be rearranged to have fd field first,
> also QEMU_PACKED is not necessary.

Sorry, I was unclear.  The kernel sees fd as data[0], that's the point
of the structure, so re-arranging it makes it useless.  Thanks,

Alex

> > Where data is the start of a variable sized array.  The data type of the
> > array depends on the flags.  The purpose of VFIOIRQSetFD is simply to
> > make a data type that I don't need to dynamically allocate.  You can
> > find other cases for MSI and MSIX where we don't know the array size and
> > do malloc the whole structure.  For this interrupt type we know there's
> > only one entry.  If there's a better way to do this, let me know.  VFIO
> > is only available on Linux hosts, so I have no particular reason to
> > avoid GNU extensions.
> >
> >> > +
> >> > +static int vfio_enable_intx(VFIODevice *vdev)
> >> > +{
> >> > +    VFIOIRQSetFD irq_set_fd = {
> >> > +        .irq_set = {
> >> > +            .argsz = sizeof(irq_set_fd),
> >> > +            .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
> >> > +            .index = VFIO_PCI_INTX_IRQ_INDEX,
> >> > +            .start = 0,
> >> > +            .count = 1,
> >> > +        },
> >>
> >> Here the field is not even initialized.
> >
> > It's initialized later...
> >
> >> > +    };
> >> > +    uint8_t pin = vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1);
> >> > +    int ret;
> >> > +
> >> > +    if (vdev->intx.disabled || !pin) {
> >> > +        return 0;
> >> > +    }
> >> > +
> >> > +    vfio_disable_interrupts(vdev);
> >> > +
> >> > +    vdev->intx.pin = pin - 1; /* Pin A (1) -> irq[0] */
> >> > +    ret = event_notifier_init(&vdev->intx.interrupt, 0);
> >> > +    if (ret) {
> >> > +        error_report("vfio: Error: event_notifier_init failed\n");
> >> > +        return ret;
> >> > +    }
> >> > +
> >> > +    irq_set_fd.fd = event_notifier_get_fd(&vdev->intx.interrupt);
> >
> > Here.
> >
> > Thanks,
> > Alex
> >

On Fri, Oct 5, 2012 at 5:33 PM, Alex Williamson
<alex.williamson@redhat.com> wrote:
> On Fri, 2012-10-05 at 17:22 +0000, Blue Swirl wrote:
>> On Fri, Oct 5, 2012 at 5:11 PM, Alex Williamson
>> <alex.williamson@redhat.com> wrote:
>> > On Fri, 2012-10-05 at 16:54 +0000, Blue Swirl wrote:
>> >> On Wed, Sep 26, 2012 at 5:19 PM, Alex Williamson
>> >> <alex.williamson@redhat.com> wrote:
>> >> > +
>> >> > +typedef struct QEMU_PACKED VFIOIRQSetFD {
>> >> > +    struct vfio_irq_set irq_set;
>> >> > +    int32_t fd;
>> >> > +} VFIOIRQSetFD;
>> >>
>> >> I'm now getting this error from Clang:
>> >>
>> >> /src/qemu/hw/vfio_pci.c:126:25: error: field 'irq_set' with variable
>> >> sized type 'struct vfio_irq_set' not at the end of a struct or class
>> >> is a GNU extension [-Werror,-Wgnu]
>> >>     struct vfio_irq_set irq_set;
>> >>
>> >> Does the kernel really use the fd field, isn't it implicit from the
>> >> ioctl fd or are they different?
>> >
>> > The kernel side is defined as:
>> >
>> > struct vfio_irq_set {
>> >         __u32   argsz;
>> >         __u32   flags;
>> >         __u32   index;
>> >         __u32   start;
>> >         __u32   count;
>> >         __u8    data[];
>> > };
>>
>> Then the kernel only expects vfio_irq_set structure, not VFIOIRQSetFD,
>> so you should use &irq_set_fd.irq_set instead of &irq_set_fd for the
>> ioctl(). Then VFIOIRQSetFD can be rearranged to have fd field first,
>> also QEMU_PACKED is not necessary.
>
> Sorry, I was unclear.  The kernel sees fd as data[0], that's the point
> of the structure, so re-arranging it makes it useless.  Thanks,

I see. The example in GCC shows how to statically initialize flexible
array members properly but it does not seem to work:
http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html

Also, Clang does not like that syntax either.

Maybe it's best to use g_malloc with room for the extra int.

>
> Alex
>
>> > Where data is the start of a variable sized array.  The data type of the
>> > array depends on the flags.  The purpose of VFIOIRQSetFD is simply to
>> > make a data type that I don't need to dynamically allocate.  You can
>> > find other cases for MSI and MSIX where we don't know the array size and
>> > do malloc the whole structure.  For this interrupt type we know there's
>> > only one entry.  If there's a better way to do this, let me know.  VFIO
>> > is only available on Linux hosts, so I have no particular reason to
>> > avoid GNU extensions.
>> >
>> >> > +
>> >> > +static int vfio_enable_intx(VFIODevice *vdev)
>> >> > +{
>> >> > +    VFIOIRQSetFD irq_set_fd = {
>> >> > +        .irq_set = {
>> >> > +            .argsz = sizeof(irq_set_fd),
>> >> > +            .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
>> >> > +            .index = VFIO_PCI_INTX_IRQ_INDEX,
>> >> > +            .start = 0,
>> >> > +            .count = 1,
>> >> > +        },
>> >>
>> >> Here the field is not even initialized.
>> >
>> > It's initialized later...
>> >
>> >> > +    };
>> >> > +    uint8_t pin = vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1);
>> >> > +    int ret;
>> >> > +
>> >> > +    if (vdev->intx.disabled || !pin) {
>> >> > +        return 0;
>> >> > +    }
>> >> > +
>> >> > +    vfio_disable_interrupts(vdev);
>> >> > +
>> >> > +    vdev->intx.pin = pin - 1; /* Pin A (1) -> irq[0] */
>> >> > +    ret = event_notifier_init(&vdev->intx.interrupt, 0);
>> >> > +    if (ret) {
>> >> > +        error_report("vfio: Error: event_notifier_init failed\n");
>> >> > +        return ret;
>> >> > +    }
>> >> > +
>> >> > +    irq_set_fd.fd = event_notifier_get_fd(&vdev->intx.interrupt);
>> >
>> > Here.
>> >
>> > Thanks,
>> > Alex
>> >
>
>
>

On Fri, 2012-10-05 at 18:05 +0000, Blue Swirl wrote:
> On Fri, Oct 5, 2012 at 5:33 PM, Alex Williamson
> <alex.williamson@redhat.com> wrote:
> > On Fri, 2012-10-05 at 17:22 +0000, Blue Swirl wrote:
> >> On Fri, Oct 5, 2012 at 5:11 PM, Alex Williamson
> >> <alex.williamson@redhat.com> wrote:
> >> > On Fri, 2012-10-05 at 16:54 +0000, Blue Swirl wrote:
> >> >> On Wed, Sep 26, 2012 at 5:19 PM, Alex Williamson
> >> >> <alex.williamson@redhat.com> wrote:
> >> >> > +
> >> >> > +typedef struct QEMU_PACKED VFIOIRQSetFD {
> >> >> > +    struct vfio_irq_set irq_set;
> >> >> > +    int32_t fd;
> >> >> > +} VFIOIRQSetFD;
> >> >>
> >> >> I'm now getting this error from Clang:
> >> >>
> >> >> /src/qemu/hw/vfio_pci.c:126:25: error: field 'irq_set' with variable
> >> >> sized type 'struct vfio_irq_set' not at the end of a struct or class
> >> >> is a GNU extension [-Werror,-Wgnu]
> >> >>     struct vfio_irq_set irq_set;
> >> >>
> >> >> Does the kernel really use the fd field, isn't it implicit from the
> >> >> ioctl fd or are they different?
> >> >
> >> > The kernel side is defined as:
> >> >
> >> > struct vfio_irq_set {
> >> >         __u32   argsz;
> >> >         __u32   flags;
> >> >         __u32   index;
> >> >         __u32   start;
> >> >         __u32   count;
> >> >         __u8    data[];
> >> > };
> >>
> >> Then the kernel only expects vfio_irq_set structure, not VFIOIRQSetFD,
> >> so you should use &irq_set_fd.irq_set instead of &irq_set_fd for the
> >> ioctl(). Then VFIOIRQSetFD can be rearranged to have fd field first,
> >> also QEMU_PACKED is not necessary.
> >
> > Sorry, I was unclear.  The kernel sees fd as data[0], that's the point
> > of the structure, so re-arranging it makes it useless.  Thanks,
> 
> I see. The example in GCC shows how to statically initialize flexible
> array members properly but it does not seem to work:
> http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html

That's not going to like that the data type is actually different for
this use case.

> Also, Clang does not like that syntax either.
> 
> Maybe it's best to use g_malloc with room for the extra int.

:(  Ok, I'll write a patch to make it dynamically allocated.  Thanks,

Alex