Patchwork [v3,4/4] kvm: i386: Add classic PCI device assignment

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Submitter Jan Kiszka
Date Aug. 30, 2012, 6:30 p.m.
Message ID <503FB128.4070709@siemens.com>
Download mbox | patch
Permalink /patch/180858/
State New
Headers show

Comments

Jan Kiszka - Aug. 30, 2012, 6:30 p.m.
This adds PCI device assignment for i386 targets using the classic KVM
interfaces. This version is 100% identical to what is being maintained
in qemu-kvm for several years and is supported by libvirt as well. It is
expected to remain relevant for another couple of years until kernels
without full-features and performance-wise equivalent VFIO support are
obsolete.

A refactoring to-do that should be done in-tree is to model MSI and
MSI-X support via the generic PCI layer, similar to what VFIO is already
doing for MSI-X. This should improve the correctness and clean up the
code from duplicate logic.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Changes in v3:
 - addressed comment by Peter (changed device name to kvm-pci-assign +
   alias)
 - addressed (most) comments by Michael
 - fixed INT pin regression

 hw/kvm/Makefile.objs |    2 +-
 hw/kvm/pci-assign.c  | 1915 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/qdev-monitor.c    |    1 +
 3 files changed, 1917 insertions(+), 1 deletions(-)
 create mode 100644 hw/kvm/pci-assign.c
Jan Kiszka - Sept. 6, 2012, 8:44 a.m.
On 2012-08-30 20:30, Jan Kiszka wrote:
> This adds PCI device assignment for i386 targets using the classic KVM
> interfaces. This version is 100% identical to what is being maintained
> in qemu-kvm for several years and is supported by libvirt as well. It is
> expected to remain relevant for another couple of years until kernels
> without full-features and performance-wise equivalent VFIO support are
> obsolete.
> 
> A refactoring to-do that should be done in-tree is to model MSI and
> MSI-X support via the generic PCI layer, similar to what VFIO is already
> doing for MSI-X. This should improve the correctness and clean up the
> code from duplicate logic.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
> 
> Changes in v3:
>  - addressed comment by Peter (changed device name to kvm-pci-assign +
>    alias)
>  - addressed (most) comments by Michael
>  - fixed INT pin regression

Does someone _disagree_ that there are no open (and reasonably solvable)
issues and that this can now be merged through uq/master?

Jan
Michael S. Tsirkin - Sept. 6, 2012, 8:49 a.m.
On Thu, Sep 06, 2012 at 10:44:15AM +0200, Jan Kiszka wrote:
> On 2012-08-30 20:30, Jan Kiszka wrote:
> > This adds PCI device assignment for i386 targets using the classic KVM
> > interfaces. This version is 100% identical to what is being maintained
> > in qemu-kvm for several years and is supported by libvirt as well. It is
> > expected to remain relevant for another couple of years until kernels
> > without full-features and performance-wise equivalent VFIO support are
> > obsolete.
> > 
> > A refactoring to-do that should be done in-tree is to model MSI and
> > MSI-X support via the generic PCI layer, similar to what VFIO is already
> > doing for MSI-X. This should improve the correctness and clean up the
> > code from duplicate logic.
> > 
> > Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> > ---
> > 
> > Changes in v3:
> >  - addressed comment by Peter (changed device name to kvm-pci-assign +
> >    alias)
> >  - addressed (most) comments by Michael
> >  - fixed INT pin regression
> 
> Does someone _disagree_ that there are no open (and reasonably solvable)
> issues and that this can now be merged through uq/master?
> 
> Jan

Ugh this thread was shamelessly highjacked by coding style
bike-shedding. I am guilty to.
In hopes of making amends:

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> -- 
> Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
> Corporate Competence Center Embedded Linux
Andreas Färber - Sept. 6, 2012, 4:06 p.m.
Am 06.09.2012 10:44, schrieb Jan Kiszka:
> On 2012-08-30 20:30, Jan Kiszka wrote:
>> This adds PCI device assignment for i386 targets using the classic KVM
>> interfaces. This version is 100% identical to what is being maintained
>> in qemu-kvm for several years and is supported by libvirt as well. It is
>> expected to remain relevant for another couple of years until kernels
>> without full-features and performance-wise equivalent VFIO support are
>> obsolete.
>>
>> A refactoring to-do that should be done in-tree is to model MSI and
>> MSI-X support via the generic PCI layer, similar to what VFIO is already
>> doing for MSI-X. This should improve the correctness and clean up the
>> code from duplicate logic.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>
>> Changes in v3:
>>  - addressed comment by Peter (changed device name to kvm-pci-assign +
>>    alias)
>>  - addressed (most) comments by Michael
>>  - fixed INT pin regression
> 
> Does someone _disagree_ that there are no open (and reasonably solvable)
> issues and that this can now be merged through uq/master?

My implicit suggestion was to add a notice that new patch contributions
to the file from date yyyy-mm-dd on would be declared GPLv2+, as Paolo
has done elsewhere. That would limit the amount of people to ask for a
potential relicensing attempt.

For the record, Anthony explained on IRC that the code originated from
Xen originally and thus qemu-kvm.git does not contain the full history
anyway and that pulling in the Mercurial file history and replaying the
KVM history on top was too difficult, therefore this patch with a single
SoB by Jan.

Andreas
Jan Kiszka - Sept. 6, 2012, 4:16 p.m.
On 2012-09-06 18:06, Andreas Färber wrote:
> Am 06.09.2012 10:44, schrieb Jan Kiszka:
>> On 2012-08-30 20:30, Jan Kiszka wrote:
>>> This adds PCI device assignment for i386 targets using the classic KVM
>>> interfaces. This version is 100% identical to what is being maintained
>>> in qemu-kvm for several years and is supported by libvirt as well. It is
>>> expected to remain relevant for another couple of years until kernels
>>> without full-features and performance-wise equivalent VFIO support are
>>> obsolete.
>>>
>>> A refactoring to-do that should be done in-tree is to model MSI and
>>> MSI-X support via the generic PCI layer, similar to what VFIO is already
>>> doing for MSI-X. This should improve the correctness and clean up the
>>> code from duplicate logic.
>>>
>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>> ---
>>>
>>> Changes in v3:
>>>  - addressed comment by Peter (changed device name to kvm-pci-assign +
>>>    alias)
>>>  - addressed (most) comments by Michael
>>>  - fixed INT pin regression
>>
>> Does someone _disagree_ that there are no open (and reasonably solvable)
>> issues and that this can now be merged through uq/master?
> 
> My implicit suggestion was to add a notice that new patch contributions
> to the file from date yyyy-mm-dd on would be declared GPLv2+, as Paolo
> has done elsewhere. That would limit the amount of people to ask for a
> potential relicensing attempt.

Sorry, someone else will have to add this.

Personally I think it is pointless to worry about it here anyway as
hunting down all contributors and getting them to agree on a GPLv2+ will
take longer than the expected lifetime of this component.

Jan
Blue Swirl - Sept. 8, 2012, 7:55 a.m.
On Thu, Sep 6, 2012 at 4:06 PM, Andreas Färber <afaerber@suse.de> wrote:
> Am 06.09.2012 10:44, schrieb Jan Kiszka:
>> On 2012-08-30 20:30, Jan Kiszka wrote:
>>> This adds PCI device assignment for i386 targets using the classic KVM
>>> interfaces. This version is 100% identical to what is being maintained
>>> in qemu-kvm for several years and is supported by libvirt as well. It is
>>> expected to remain relevant for another couple of years until kernels
>>> without full-features and performance-wise equivalent VFIO support are
>>> obsolete.
>>>
>>> A refactoring to-do that should be done in-tree is to model MSI and
>>> MSI-X support via the generic PCI layer, similar to what VFIO is already
>>> doing for MSI-X. This should improve the correctness and clean up the
>>> code from duplicate logic.
>>>
>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>> ---
>>>
>>> Changes in v3:
>>>  - addressed comment by Peter (changed device name to kvm-pci-assign +
>>>    alias)
>>>  - addressed (most) comments by Michael
>>>  - fixed INT pin regression
>>
>> Does someone _disagree_ that there are no open (and reasonably solvable)
>> issues and that this can now be merged through uq/master?
>
> My implicit suggestion was to add a notice that new patch contributions
> to the file from date yyyy-mm-dd on would be declared GPLv2+, as Paolo
> has done elsewhere. That would limit the amount of people to ask for a
> potential relicensing attempt.

+1

>
> For the record, Anthony explained on IRC that the code originated from
> Xen originally and thus qemu-kvm.git does not contain the full history
> anyway and that pulling in the Mercurial file history and replaying the
> KVM history on top was too difficult, therefore this patch with a single
> SoB by Jan.
>
> Andreas
>
> --
> SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
> GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
Avi Kivity - Sept. 9, 2012, 2:13 p.m.
On 09/06/2012 11:44 AM, Jan Kiszka wrote:
> On 2012-08-30 20:30, Jan Kiszka wrote:
>> This adds PCI device assignment for i386 targets using the classic KVM
>> interfaces. This version is 100% identical to what is being maintained
>> in qemu-kvm for several years and is supported by libvirt as well. It is
>> expected to remain relevant for another couple of years until kernels
>> without full-features and performance-wise equivalent VFIO support are
>> obsolete.
>> 
>> A refactoring to-do that should be done in-tree is to model MSI and
>> MSI-X support via the generic PCI layer, similar to what VFIO is already
>> doing for MSI-X. This should improve the correctness and clean up the
>> code from duplicate logic.
>> 
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>> 
>> Changes in v3:
>>  - addressed comment by Peter (changed device name to kvm-pci-assign +
>>    alias)
>>  - addressed (most) comments by Michael
>>  - fixed INT pin regression
> 
> Does someone _disagree_ that there are no open (and reasonably solvable)
> issues and that this can now be merged through uq/master?

Is patch 4 the only one that is at v3, and the rest are to be taken from
the original posting?
Jan Kiszka - Sept. 10, 2012, 9:26 a.m.
On 2012-09-09 16:13, Avi Kivity wrote:
> On 09/06/2012 11:44 AM, Jan Kiszka wrote:
>> On 2012-08-30 20:30, Jan Kiszka wrote:
>>> This adds PCI device assignment for i386 targets using the classic KVM
>>> interfaces. This version is 100% identical to what is being maintained
>>> in qemu-kvm for several years and is supported by libvirt as well. It is
>>> expected to remain relevant for another couple of years until kernels
>>> without full-features and performance-wise equivalent VFIO support are
>>> obsolete.
>>>
>>> A refactoring to-do that should be done in-tree is to model MSI and
>>> MSI-X support via the generic PCI layer, similar to what VFIO is already
>>> doing for MSI-X. This should improve the correctness and clean up the
>>> code from duplicate logic.
>>>
>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>> ---
>>>
>>> Changes in v3:
>>>  - addressed comment by Peter (changed device name to kvm-pci-assign +
>>>    alias)
>>>  - addressed (most) comments by Michael
>>>  - fixed INT pin regression
>>
>> Does someone _disagree_ that there are no open (and reasonably solvable)
>> issues and that this can now be merged through uq/master?
> 
> Is patch 4 the only one that is at v3, and the rest are to be taken from
> the original posting?

That is correct.

Jan
Avi Kivity - Sept. 10, 2012, 12:30 p.m.
On 09/10/2012 12:26 PM, Jan Kiszka wrote:
>> 
>> Is patch 4 the only one that is at v3, and the rest are to be taken from
>> the original posting?
> 
> That is correct.

Thanks, applied to uq/master, will push shortly.

Patch

diff --git a/hw/kvm/Makefile.objs b/hw/kvm/Makefile.objs
index 226497a..f620d7f 100644
--- a/hw/kvm/Makefile.objs
+++ b/hw/kvm/Makefile.objs
@@ -1 +1 @@ 
-obj-$(CONFIG_KVM) += clock.o apic.o i8259.o ioapic.o i8254.o
+obj-$(CONFIG_KVM) += clock.o apic.o i8259.o ioapic.o i8254.o pci-assign.o
diff --git a/hw/kvm/pci-assign.c b/hw/kvm/pci-assign.c
new file mode 100644
index 0000000..05b93d9
--- /dev/null
+++ b/hw/kvm/pci-assign.c
@@ -0,0 +1,1915 @@ 
+/*
+ * Copyright (c) 2007, Neocleus Corporation.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ *
+ *  Assign a PCI device from the host to a guest VM.
+ *
+ *  This implementation uses the classic device assignment interface of KVM
+ *  and is only available on x86 hosts. It is expected to be obsoleted by VFIO
+ *  based device assignment.
+ *
+ *  Adapted for KVM (qemu-kvm) by Qumranet. QEMU version was based on qemu-kvm
+ *  revision 4144fe9d48. See its repository for the history.
+ *
+ *  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 <stdio.h>
+#include <unistd.h>
+#include <sys/io.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "hw/hw.h"
+#include "hw/pc.h"
+#include "qemu-error.h"
+#include "console.h"
+#include "hw/loader.h"
+#include "monitor.h"
+#include "range.h"
+#include "sysemu.h"
+#include "hw/pci.h"
+#include "hw/msi.h"
+#include "kvm_i386.h"
+
+#define MSIX_PAGE_SIZE 0x1000
+
+/* From linux/ioport.h */
+#define IORESOURCE_IO       0x00000100  /* Resource type */
+#define IORESOURCE_MEM      0x00000200
+#define IORESOURCE_IRQ      0x00000400
+#define IORESOURCE_DMA      0x00000800
+#define IORESOURCE_PREFETCH 0x00002000  /* No side effects */
+
+//#define DEVICE_ASSIGNMENT_DEBUG
+
+#ifdef DEVICE_ASSIGNMENT_DEBUG
+#define DEBUG(fmt, ...)                                       \
+    do {                                                      \
+        fprintf(stderr, "%s: " fmt, __func__ , __VA_ARGS__);  \
+    } while (0)
+#else
+#define DEBUG(fmt, ...)
+#endif
+
+typedef struct PCIRegion {
+    int type;           /* Memory or port I/O */
+    int valid;
+    uint64_t base_addr;
+    uint64_t size;    /* size of the region */
+    int resource_fd;
+} PCIRegion;
+
+typedef struct PCIDevRegions {
+    uint8_t bus, dev, func; /* Bus inside domain, device and function */
+    int irq;                /* IRQ number */
+    uint16_t region_number; /* number of active regions */
+
+    /* Port I/O or MMIO Regions */
+    PCIRegion regions[PCI_NUM_REGIONS - 1];
+    int config_fd;
+} PCIDevRegions;
+
+typedef struct AssignedDevRegion {
+    MemoryRegion container;
+    MemoryRegion real_iomem;
+    union {
+        uint8_t *r_virtbase; /* mmapped access address for memory regions */
+        uint32_t r_baseport; /* the base guest port for I/O regions */
+    } u;
+    pcibus_t e_size;    /* emulated size of region in bytes */
+    pcibus_t r_size;    /* real size of region in bytes */
+    PCIRegion *region;
+} AssignedDevRegion;
+
+#define ASSIGNED_DEVICE_PREFER_MSI_BIT  0
+#define ASSIGNED_DEVICE_SHARE_INTX_BIT  1
+
+#define ASSIGNED_DEVICE_PREFER_MSI_MASK (1 << ASSIGNED_DEVICE_PREFER_MSI_BIT)
+#define ASSIGNED_DEVICE_SHARE_INTX_MASK (1 << ASSIGNED_DEVICE_SHARE_INTX_BIT)
+
+typedef struct MSIXTableEntry {
+    uint32_t addr_lo;
+    uint32_t addr_hi;
+    uint32_t data;
+    uint32_t ctrl;
+} MSIXTableEntry;
+
+typedef enum AssignedIRQType {
+    ASSIGNED_IRQ_NONE = 0,
+    ASSIGNED_IRQ_INTX_HOST_INTX,
+    ASSIGNED_IRQ_INTX_HOST_MSI,
+    ASSIGNED_IRQ_MSI,
+    ASSIGNED_IRQ_MSIX
+} AssignedIRQType;
+
+typedef struct AssignedDevice {
+    PCIDevice dev;
+    PCIHostDeviceAddress host;
+    uint32_t dev_id;
+    uint32_t features;
+    int intpin;
+    AssignedDevRegion v_addrs[PCI_NUM_REGIONS - 1];
+    PCIDevRegions real_device;
+    PCIINTxRoute intx_route;
+    AssignedIRQType assigned_irq_type;
+    struct {
+#define ASSIGNED_DEVICE_CAP_MSI (1 << 0)
+#define ASSIGNED_DEVICE_CAP_MSIX (1 << 1)
+        uint32_t available;
+#define ASSIGNED_DEVICE_MSI_ENABLED (1 << 0)
+#define ASSIGNED_DEVICE_MSIX_ENABLED (1 << 1)
+#define ASSIGNED_DEVICE_MSIX_MASKED (1 << 2)
+        uint32_t state;
+    } cap;
+    uint8_t emulate_config_read[PCI_CONFIG_SPACE_SIZE];
+    uint8_t emulate_config_write[PCI_CONFIG_SPACE_SIZE];
+    int msi_virq_nr;
+    int *msi_virq;
+    MSIXTableEntry *msix_table;
+    target_phys_addr_t msix_table_addr;
+    uint16_t msix_max;
+    MemoryRegion mmio;
+    char *configfd_name;
+    int32_t bootindex;
+} AssignedDevice;
+
+static void assigned_dev_update_irq_routing(PCIDevice *dev);
+
+static void assigned_dev_load_option_rom(AssignedDevice *dev);
+
+static void assigned_dev_unregister_msix_mmio(AssignedDevice *dev);
+
+static uint64_t assigned_dev_ioport_rw(AssignedDevRegion *dev_region,
+                                       target_phys_addr_t addr, int size,
+                                       uint64_t *data)
+{
+    uint64_t val = 0;
+    int fd = dev_region->region->resource_fd;
+
+    if (fd >= 0) {
+        if (data) {
+            DEBUG("pwrite data=%" PRIx64 ", size=%d, e_phys=" TARGET_FMT_plx
+                  ", addr="TARGET_FMT_plx"\n", *data, size, addr, addr);
+            if (pwrite(fd, data, size, addr) != size) {
+                error_report("%s - pwrite failed %s",
+                             __func__, strerror(errno));
+            }
+        } else {
+            if (pread(fd, &val, size, addr) != size) {
+                error_report("%s - pread failed %s",
+                             __func__, strerror(errno));
+                val = (1UL << (size * 8)) - 1;
+            }
+            DEBUG("pread val=%" PRIx64 ", size=%d, e_phys=" TARGET_FMT_plx
+                  ", addr=" TARGET_FMT_plx "\n", val, size, addr, addr);
+        }
+    } else {
+        uint32_t port = addr + dev_region->u.r_baseport;
+
+        if (data) {
+            DEBUG("out data=%" PRIx64 ", size=%d, e_phys=" TARGET_FMT_plx
+                  ", host=%x\n", *data, size, addr, port);
+            switch (size) {
+            case 1:
+                outb(*data, port);
+                break;
+            case 2:
+                outw(*data, port);
+                break;
+            case 4:
+                outl(*data, port);
+                break;
+            }
+        } else {
+            switch (size) {
+            case 1:
+                val = inb(port);
+                break;
+            case 2:
+                val = inw(port);
+                break;
+            case 4:
+                val = inl(port);
+                break;
+            }
+            DEBUG("in data=%" PRIx64 ", size=%d, e_phys=" TARGET_FMT_plx
+                  ", host=%x\n", val, size, addr, port);
+        }
+    }
+    return val;
+}
+
+static void assigned_dev_ioport_write(void *opaque, target_phys_addr_t addr,
+                                      uint64_t data, unsigned size)
+{
+    assigned_dev_ioport_rw(opaque, addr, size, &data);
+}
+
+static uint64_t assigned_dev_ioport_read(void *opaque,
+                                         target_phys_addr_t addr, unsigned size)
+{
+    return assigned_dev_ioport_rw(opaque, addr, size, NULL);
+}
+
+static uint32_t slow_bar_readb(void *opaque, target_phys_addr_t addr)
+{
+    AssignedDevRegion *d = opaque;
+    uint8_t *in = d->u.r_virtbase + addr;
+    uint32_t r;
+
+    r = *in;
+    DEBUG("slow_bar_readl addr=0x" TARGET_FMT_plx " val=0x%08x\n", addr, r);
+
+    return r;
+}
+
+static uint32_t slow_bar_readw(void *opaque, target_phys_addr_t addr)
+{
+    AssignedDevRegion *d = opaque;
+    uint16_t *in = (uint16_t *)(d->u.r_virtbase + addr);
+    uint32_t r;
+
+    r = *in;
+    DEBUG("slow_bar_readl addr=0x" TARGET_FMT_plx " val=0x%08x\n", addr, r);
+
+    return r;
+}
+
+static uint32_t slow_bar_readl(void *opaque, target_phys_addr_t addr)
+{
+    AssignedDevRegion *d = opaque;
+    uint32_t *in = (uint32_t *)(d->u.r_virtbase + addr);
+    uint32_t r;
+
+    r = *in;
+    DEBUG("slow_bar_readl addr=0x" TARGET_FMT_plx " val=0x%08x\n", addr, r);
+
+    return r;
+}
+
+static void slow_bar_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+    AssignedDevRegion *d = opaque;
+    uint8_t *out = d->u.r_virtbase + addr;
+
+    DEBUG("slow_bar_writeb addr=0x" TARGET_FMT_plx " val=0x%02x\n", addr, val);
+    *out = val;
+}
+
+static void slow_bar_writew(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+    AssignedDevRegion *d = opaque;
+    uint16_t *out = (uint16_t *)(d->u.r_virtbase + addr);
+
+    DEBUG("slow_bar_writew addr=0x" TARGET_FMT_plx " val=0x%04x\n", addr, val);
+    *out = val;
+}
+
+static void slow_bar_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+    AssignedDevRegion *d = opaque;
+    uint32_t *out = (uint32_t *)(d->u.r_virtbase + addr);
+
+    DEBUG("slow_bar_writel addr=0x" TARGET_FMT_plx " val=0x%08x\n", addr, val);
+    *out = val;
+}
+
+static const MemoryRegionOps slow_bar_ops = {
+    .old_mmio = {
+        .read = { slow_bar_readb, slow_bar_readw, slow_bar_readl, },
+        .write = { slow_bar_writeb, slow_bar_writew, slow_bar_writel, },
+    },
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void assigned_dev_iomem_setup(PCIDevice *pci_dev, int region_num,
+                                     pcibus_t e_size)
+{
+    AssignedDevice *r_dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    AssignedDevRegion *region = &r_dev->v_addrs[region_num];
+    PCIRegion *real_region = &r_dev->real_device.regions[region_num];
+
+    if (e_size > 0) {
+        memory_region_init(&region->container, "assigned-dev-container",
+                           e_size);
+        memory_region_add_subregion(&region->container, 0, &region->real_iomem);
+
+        /* deal with MSI-X MMIO page */
+        if (real_region->base_addr <= r_dev->msix_table_addr &&
+                real_region->base_addr + real_region->size >
+                r_dev->msix_table_addr) {
+            uint64_t offset = r_dev->msix_table_addr - real_region->base_addr;
+
+            memory_region_add_subregion_overlap(&region->container,
+                                                offset,
+                                                &r_dev->mmio,
+                                                1);
+        }
+    }
+}
+
+static const MemoryRegionOps assigned_dev_ioport_ops = {
+    .read = assigned_dev_ioport_read,
+    .write = assigned_dev_ioport_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void assigned_dev_ioport_setup(PCIDevice *pci_dev, int region_num,
+                                      pcibus_t size)
+{
+    AssignedDevice *r_dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    AssignedDevRegion *region = &r_dev->v_addrs[region_num];
+
+    region->e_size = size;
+    memory_region_init(&region->container, "assigned-dev-container", size);
+    memory_region_init_io(&region->real_iomem, &assigned_dev_ioport_ops,
+                          r_dev->v_addrs + region_num,
+                          "assigned-dev-iomem", size);
+    memory_region_add_subregion(&region->container, 0, &region->real_iomem);
+}
+
+static uint32_t assigned_dev_pci_read(PCIDevice *d, int pos, int len)
+{
+    AssignedDevice *pci_dev = DO_UPCAST(AssignedDevice, dev, d);
+    uint32_t val;
+    ssize_t ret;
+    int fd = pci_dev->real_device.config_fd;
+
+again:
+    ret = pread(fd, &val, len, pos);
+    if (ret != len) {
+        if ((ret < 0) && (errno == EINTR || errno == EAGAIN)) {
+            goto again;
+        }
+
+        hw_error("pci read failed, ret = %zd errno = %d\n", ret, errno);
+    }
+
+    return val;
+}
+
+static uint8_t assigned_dev_pci_read_byte(PCIDevice *d, int pos)
+{
+    return (uint8_t)assigned_dev_pci_read(d, pos, 1);
+}
+
+static void assigned_dev_pci_write(PCIDevice *d, int pos, uint32_t val, int len)
+{
+    AssignedDevice *pci_dev = DO_UPCAST(AssignedDevice, dev, d);
+    ssize_t ret;
+    int fd = pci_dev->real_device.config_fd;
+
+again:
+    ret = pwrite(fd, &val, len, pos);
+    if (ret != len) {
+        if ((ret < 0) && (errno == EINTR || errno == EAGAIN)) {
+            goto again;
+        }
+
+        hw_error("pci write failed, ret = %zd errno = %d\n", ret, errno);
+    }
+}
+
+static void assigned_dev_emulate_config_read(AssignedDevice *dev,
+                                             uint32_t offset, uint32_t len)
+{
+    memset(dev->emulate_config_read + offset, 0xff, len);
+}
+
+static void assigned_dev_direct_config_read(AssignedDevice *dev,
+                                            uint32_t offset, uint32_t len)
+{
+    memset(dev->emulate_config_read + offset, 0, len);
+}
+
+static void assigned_dev_direct_config_write(AssignedDevice *dev,
+                                             uint32_t offset, uint32_t len)
+{
+    memset(dev->emulate_config_write + offset, 0, len);
+}
+
+static uint8_t pci_find_cap_offset(PCIDevice *d, uint8_t cap, uint8_t start)
+{
+    int id;
+    int max_cap = 48;
+    int pos = start ? start : PCI_CAPABILITY_LIST;
+    int status;
+
+    status = assigned_dev_pci_read_byte(d, PCI_STATUS);
+    if ((status & PCI_STATUS_CAP_LIST) == 0) {
+        return 0;
+    }
+
+    while (max_cap--) {
+        pos = assigned_dev_pci_read_byte(d, pos);
+        if (pos < 0x40) {
+            break;
+        }
+
+        pos &= ~3;
+        id = assigned_dev_pci_read_byte(d, pos + PCI_CAP_LIST_ID);
+
+        if (id == 0xff) {
+            break;
+        }
+        if (id == cap) {
+            return pos;
+        }
+
+        pos += PCI_CAP_LIST_NEXT;
+    }
+    return 0;
+}
+
+static int assigned_dev_register_regions(PCIRegion *io_regions,
+                                         unsigned long regions_num,
+                                         AssignedDevice *pci_dev)
+{
+    uint32_t i;
+    PCIRegion *cur_region = io_regions;
+
+    for (i = 0; i < regions_num; i++, cur_region++) {
+        if (!cur_region->valid) {
+            continue;
+        }
+
+        /* handle memory io regions */
+        if (cur_region->type & IORESOURCE_MEM) {
+            int t = cur_region->type & IORESOURCE_PREFETCH
+                ? PCI_BASE_ADDRESS_MEM_PREFETCH
+                : PCI_BASE_ADDRESS_SPACE_MEMORY;
+
+            /* map physical memory */
+            pci_dev->v_addrs[i].u.r_virtbase = mmap(NULL, cur_region->size,
+                                                    PROT_WRITE | PROT_READ,
+                                                    MAP_SHARED,
+                                                    cur_region->resource_fd,
+                                                    (off_t)0);
+
+            if (pci_dev->v_addrs[i].u.r_virtbase == MAP_FAILED) {
+                pci_dev->v_addrs[i].u.r_virtbase = NULL;
+                error_report("%s: Error: Couldn't mmap 0x%" PRIx64 "!",
+                             __func__, cur_region->base_addr);
+                return -1;
+            }
+
+            pci_dev->v_addrs[i].r_size = cur_region->size;
+            pci_dev->v_addrs[i].e_size = 0;
+
+            /* add offset */
+            pci_dev->v_addrs[i].u.r_virtbase +=
+                (cur_region->base_addr & 0xFFF);
+
+            if (cur_region->size & 0xFFF) {
+                error_report("PCI region %d at address 0x%" PRIx64 " has "
+                             "size 0x%" PRIx64 ", which is not a multiple of "
+                             "4K.  You might experience some performance hit "
+                             "due to that.",
+                             i, cur_region->base_addr, cur_region->size);
+                memory_region_init_io(&pci_dev->v_addrs[i].real_iomem,
+                                      &slow_bar_ops, &pci_dev->v_addrs[i],
+                                      "assigned-dev-slow-bar",
+                                      cur_region->size);
+            } else {
+                void *virtbase = pci_dev->v_addrs[i].u.r_virtbase;
+                char name[32];
+                snprintf(name, sizeof(name), "%s.bar%d",
+                         object_get_typename(OBJECT(pci_dev)), i);
+                memory_region_init_ram_ptr(&pci_dev->v_addrs[i].real_iomem,
+                                           name, cur_region->size,
+                                           virtbase);
+                vmstate_register_ram(&pci_dev->v_addrs[i].real_iomem,
+                                     &pci_dev->dev.qdev);
+            }
+
+            assigned_dev_iomem_setup(&pci_dev->dev, i, cur_region->size);
+            pci_register_bar((PCIDevice *) pci_dev, i, t,
+                             &pci_dev->v_addrs[i].container);
+            continue;
+        } else {
+            /* handle port io regions */
+            uint32_t val;
+            int ret;
+
+            /* Test kernel support for ioport resource read/write.  Old
+             * kernels return EIO.  New kernels only allow 1/2/4 byte reads
+             * so should return EINVAL for a 3 byte read */
+            ret = pread(pci_dev->v_addrs[i].region->resource_fd, &val, 3, 0);
+            if (ret >= 0) {
+                error_report("Unexpected return from I/O port read: %d", ret);
+                abort();
+            } else if (errno != EINVAL) {
+                error_report("Kernel doesn't support ioport resource "
+                             "access, hiding this region.");
+                close(pci_dev->v_addrs[i].region->resource_fd);
+                cur_region->valid = 0;
+                continue;
+            }
+
+            pci_dev->v_addrs[i].u.r_baseport = cur_region->base_addr;
+            pci_dev->v_addrs[i].r_size = cur_region->size;
+            pci_dev->v_addrs[i].e_size = 0;
+
+            assigned_dev_ioport_setup(&pci_dev->dev, i, cur_region->size);
+            pci_register_bar((PCIDevice *) pci_dev, i,
+                             PCI_BASE_ADDRESS_SPACE_IO,
+                             &pci_dev->v_addrs[i].container);
+        }
+    }
+
+    /* success */
+    return 0;
+}
+
+static int get_real_id(const char *devpath, const char *idname, uint16_t *val)
+{
+    FILE *f;
+    char name[128];
+    long id;
+
+    snprintf(name, sizeof(name), "%s%s", devpath, idname);
+    f = fopen(name, "r");
+    if (f == NULL) {
+        error_report("%s: %s: %m", __func__, name);
+        return -1;
+    }
+    if (fscanf(f, "%li\n", &id) == 1) {
+        *val = id;
+    } else {
+        return -1;
+    }
+    fclose(f);
+
+    return 0;
+}
+
+static int get_real_vendor_id(const char *devpath, uint16_t *val)
+{
+    return get_real_id(devpath, "vendor", val);
+}
+
+static int get_real_device_id(const char *devpath, uint16_t *val)
+{
+    return get_real_id(devpath, "device", val);
+}
+
+static int get_real_device(AssignedDevice *pci_dev, uint16_t r_seg,
+                           uint8_t r_bus, uint8_t r_dev, uint8_t r_func)
+{
+    char dir[128], name[128];
+    int fd, r = 0, v;
+    FILE *f;
+    uint64_t start, end, size, flags;
+    uint16_t id;
+    PCIRegion *rp;
+    PCIDevRegions *dev = &pci_dev->real_device;
+
+    dev->region_number = 0;
+
+    snprintf(dir, sizeof(dir), "/sys/bus/pci/devices/%04x:%02x:%02x.%x/",
+             r_seg, r_bus, r_dev, r_func);
+
+    snprintf(name, sizeof(name), "%sconfig", dir);
+
+    if (pci_dev->configfd_name && *pci_dev->configfd_name) {
+        if (qemu_isdigit(pci_dev->configfd_name[0])) {
+            dev->config_fd = strtol(pci_dev->configfd_name, NULL, 0);
+        } else {
+            dev->config_fd = monitor_get_fd(cur_mon, pci_dev->configfd_name);
+            if (dev->config_fd < 0) {
+                error_report("%s: (%s) unkown", __func__,
+                             pci_dev->configfd_name);
+                return 1;
+            }
+        }
+    } else {
+        dev->config_fd = open(name, O_RDWR);
+
+        if (dev->config_fd == -1) {
+            error_report("%s: %s: %m", __func__, name);
+            return 1;
+        }
+    }
+again:
+    r = read(dev->config_fd, pci_dev->dev.config,
+             pci_config_size(&pci_dev->dev));
+    if (r < 0) {
+        if (errno == EINTR || errno == EAGAIN) {
+            goto again;
+        }
+        error_report("%s: read failed, errno = %d", __func__, errno);
+    }
+
+    /* Restore or clear multifunction, this is always controlled by qemu */
+    if (pci_dev->dev.cap_present & QEMU_PCI_CAP_MULTIFUNCTION) {
+        pci_dev->dev.config[PCI_HEADER_TYPE] |= PCI_HEADER_TYPE_MULTI_FUNCTION;
+    } else {
+        pci_dev->dev.config[PCI_HEADER_TYPE] &= ~PCI_HEADER_TYPE_MULTI_FUNCTION;
+    }
+
+    /* 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(&pci_dev->dev.config[PCI_BASE_ADDRESS_0], 0, 24);
+    memset(&pci_dev->dev.config[PCI_ROM_ADDRESS], 0, 4);
+
+    snprintf(name, sizeof(name), "%sresource", dir);
+
+    f = fopen(name, "r");
+    if (f == NULL) {
+        error_report("%s: %s: %m", __func__, name);
+        return 1;
+    }
+
+    for (r = 0; r < PCI_ROM_SLOT; r++) {
+        if (fscanf(f, "%" SCNi64 " %" SCNi64 " %" SCNi64 "\n",
+                   &start, &end, &flags) != 3) {
+            break;
+        }
+
+        rp = dev->regions + r;
+        rp->valid = 0;
+        rp->resource_fd = -1;
+        size = end - start + 1;
+        flags &= IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH;
+        if (size == 0 || (flags & ~IORESOURCE_PREFETCH) == 0) {
+            continue;
+        }
+        if (flags & IORESOURCE_MEM) {
+            flags &= ~IORESOURCE_IO;
+        } else {
+            flags &= ~IORESOURCE_PREFETCH;
+        }
+        snprintf(name, sizeof(name), "%sresource%d", dir, r);
+        fd = open(name, O_RDWR);
+        if (fd == -1) {
+            continue;
+        }
+        rp->resource_fd = fd;
+
+        rp->type = flags;
+        rp->valid = 1;
+        rp->base_addr = start;
+        rp->size = size;
+        pci_dev->v_addrs[r].region = rp;
+        DEBUG("region %d size %" PRIu64 " start 0x%" PRIx64
+              " type %d resource_fd %d\n",
+              r, rp->size, start, rp->type, rp->resource_fd);
+    }
+
+    fclose(f);
+
+    /* read and fill vendor ID */
+    v = get_real_vendor_id(dir, &id);
+    if (v) {
+        return 1;
+    }
+    pci_dev->dev.config[0] = id & 0xff;
+    pci_dev->dev.config[1] = (id & 0xff00) >> 8;
+
+    /* read and fill device ID */
+    v = get_real_device_id(dir, &id);
+    if (v) {
+        return 1;
+    }
+    pci_dev->dev.config[2] = id & 0xff;
+    pci_dev->dev.config[3] = (id & 0xff00) >> 8;
+
+    pci_word_test_and_clear_mask(pci_dev->emulate_config_write + PCI_COMMAND,
+                                 PCI_COMMAND_MASTER | PCI_COMMAND_INTX_DISABLE);
+
+    dev->region_number = r;
+    return 0;
+}
+
+static void free_msi_virqs(AssignedDevice *dev)
+{
+    int i;
+
+    for (i = 0; i < dev->msi_virq_nr; i++) {
+        if (dev->msi_virq[i] >= 0) {
+            kvm_irqchip_release_virq(kvm_state, dev->msi_virq[i]);
+            dev->msi_virq[i] = -1;
+        }
+    }
+    g_free(dev->msi_virq);
+    dev->msi_virq = NULL;
+    dev->msi_virq_nr = 0;
+}
+
+static void free_assigned_device(AssignedDevice *dev)
+{
+    int i;
+
+    if (dev->cap.available & ASSIGNED_DEVICE_CAP_MSIX) {
+        assigned_dev_unregister_msix_mmio(dev);
+    }
+    for (i = 0; i < dev->real_device.region_number; i++) {
+        PCIRegion *pci_region = &dev->real_device.regions[i];
+        AssignedDevRegion *region = &dev->v_addrs[i];
+
+        if (!pci_region->valid) {
+            continue;
+        }
+        if (pci_region->type & IORESOURCE_IO) {
+            if (region->u.r_baseport) {
+                memory_region_del_subregion(&region->container,
+                                            &region->real_iomem);
+                memory_region_destroy(&region->real_iomem);
+                memory_region_destroy(&region->container);
+            }
+        } else if (pci_region->type & IORESOURCE_MEM) {
+            if (region->u.r_virtbase) {
+                memory_region_del_subregion(&region->container,
+                                            &region->real_iomem);
+
+                /* Remove MSI-X table subregion */
+                if (pci_region->base_addr <= dev->msix_table_addr &&
+                    pci_region->base_addr + pci_region->size >
+                    dev->msix_table_addr) {
+                    memory_region_del_subregion(&region->container,
+                                                &dev->mmio);
+                }
+
+                memory_region_destroy(&region->real_iomem);
+                memory_region_destroy(&region->container);
+                if (munmap(region->u.r_virtbase,
+                           (pci_region->size + 0xFFF) & 0xFFFFF000)) {
+                    error_report("Failed to unmap assigned device region: %s",
+                                 strerror(errno));
+                }
+            }
+        }
+        if (pci_region->resource_fd >= 0) {
+            close(pci_region->resource_fd);
+        }
+    }
+
+    if (dev->real_device.config_fd >= 0) {
+        close(dev->real_device.config_fd);
+    }
+
+    free_msi_virqs(dev);
+}
+
+static void assign_failed_examine(AssignedDevice *dev)
+{
+    char name[PATH_MAX], dir[PATH_MAX], driver[PATH_MAX] = {}, *ns;
+    uint16_t vendor_id, device_id;
+    int r;
+
+    snprintf(dir, sizeof(dir), "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/",
+            dev->host.domain, dev->host.bus, dev->host.slot,
+            dev->host.function);
+
+    snprintf(name, sizeof(name), "%sdriver", dir);
+
+    r = readlink(name, driver, sizeof(driver));
+    if ((r <= 0) || r >= sizeof(driver)) {
+        goto fail;
+    }
+
+    ns = strrchr(driver, '/');
+    if (!ns) {
+        goto fail;
+    }
+
+    ns++;
+
+    if (get_real_vendor_id(dir, &vendor_id) ||
+        get_real_device_id(dir, &device_id)) {
+        goto fail;
+    }
+
+    error_report("*** The driver '%s' is occupying your device "
+                 "%04x:%02x:%02x.%x.",
+                 ns, dev->host.domain, dev->host.bus, dev->host.slot,
+                 dev->host.function);
+    error_report("***");
+    error_report("*** You can try the following commands to free it:");
+    error_report("***");
+    error_report("*** $ echo \"%04x %04x\" > /sys/bus/pci/drivers/pci-stub/"
+                 "new_id", vendor_id, device_id);
+    error_report("*** $ echo \"%04x:%02x:%02x.%x\" > /sys/bus/pci/drivers/"
+                 "%s/unbind",
+                 dev->host.domain, dev->host.bus, dev->host.slot,
+                 dev->host.function, ns);
+    error_report("*** $ echo \"%04x:%02x:%02x.%x\" > /sys/bus/pci/drivers/"
+                 "pci-stub/bind",
+                 dev->host.domain, dev->host.bus, dev->host.slot,
+                 dev->host.function);
+    error_report("*** $ echo \"%04x %04x\" > /sys/bus/pci/drivers/pci-stub"
+                 "/remove_id", vendor_id, device_id);
+    error_report("***");
+
+    return;
+
+fail:
+    error_report("Couldn't find out why.");
+}
+
+static int assign_device(AssignedDevice *dev)
+{
+    uint32_t flags = KVM_DEV_ASSIGN_ENABLE_IOMMU;
+    int r;
+
+    /* Only pass non-zero PCI segment to capable module */
+    if (!kvm_check_extension(kvm_state, KVM_CAP_PCI_SEGMENT) &&
+        dev->host.domain) {
+        error_report("Can't assign device inside non-zero PCI segment "
+                     "as this KVM module doesn't support it.");
+        return -ENODEV;
+    }
+
+    if (!kvm_check_extension(kvm_state, KVM_CAP_IOMMU)) {
+        error_report("No IOMMU found.  Unable to assign device \"%s\"",
+                     dev->dev.qdev.id);
+        return -ENODEV;
+    }
+
+    if (dev->features & ASSIGNED_DEVICE_SHARE_INTX_MASK &&
+        kvm_has_intx_set_mask()) {
+        flags |= KVM_DEV_ASSIGN_PCI_2_3;
+    }
+
+    r = kvm_device_pci_assign(kvm_state, &dev->host, flags, &dev->dev_id);
+    if (r < 0) {
+        error_report("Failed to assign device \"%s\" : %s",
+                     dev->dev.qdev.id, strerror(-r));
+
+        switch (r) {
+        case -EBUSY:
+            assign_failed_examine(dev);
+            break;
+        default:
+            break;
+        }
+    }
+    return r;
+}
+
+static bool check_irqchip_in_kernel(void)
+{
+    if (kvm_irqchip_in_kernel()) {
+        return true;
+    }
+    error_report("pci-assign: error: requires KVM with in-kernel irqchip "
+                 "enabled");
+    return false;
+}
+
+static int assign_intx(AssignedDevice *dev)
+{
+    AssignedIRQType new_type;
+    PCIINTxRoute intx_route;
+    bool intx_host_msi;
+    int r;
+
+    /* Interrupt PIN 0 means don't use INTx */
+    if (assigned_dev_pci_read_byte(&dev->dev, PCI_INTERRUPT_PIN) == 0) {
+        pci_device_set_intx_routing_notifier(&dev->dev, NULL);
+        return 0;
+    }
+
+    if (!check_irqchip_in_kernel()) {
+        return -ENOTSUP;
+    }
+
+    pci_device_set_intx_routing_notifier(&dev->dev,
+                                         assigned_dev_update_irq_routing);
+
+    intx_route = pci_device_route_intx_to_irq(&dev->dev, dev->intpin);
+    assert(intx_route.mode != PCI_INTX_INVERTED);
+
+    if (dev->intx_route.mode == intx_route.mode &&
+        dev->intx_route.irq == intx_route.irq) {
+        return 0;
+    }
+
+    switch (dev->assigned_irq_type) {
+    case ASSIGNED_IRQ_INTX_HOST_INTX:
+    case ASSIGNED_IRQ_INTX_HOST_MSI:
+        intx_host_msi = dev->assigned_irq_type == ASSIGNED_IRQ_INTX_HOST_MSI;
+        r = kvm_device_intx_deassign(kvm_state, dev->dev_id, intx_host_msi);
+        break;
+    case ASSIGNED_IRQ_MSI:
+        r = kvm_device_msi_deassign(kvm_state, dev->dev_id);
+        break;
+    case ASSIGNED_IRQ_MSIX:
+        r = kvm_device_msix_deassign(kvm_state, dev->dev_id);
+        break;
+    default:
+        r = 0;
+        break;
+    }
+    if (r) {
+        perror("assign_intx: deassignment of previous interrupt failed");
+    }
+    dev->assigned_irq_type = ASSIGNED_IRQ_NONE;
+
+    if (intx_route.mode == PCI_INTX_DISABLED) {
+        dev->intx_route = intx_route;
+        return 0;
+    }
+
+retry:
+    if (dev->features & ASSIGNED_DEVICE_PREFER_MSI_MASK &&
+        dev->cap.available & ASSIGNED_DEVICE_CAP_MSI) {
+        intx_host_msi = true;
+        new_type = ASSIGNED_IRQ_INTX_HOST_MSI;
+    } else {
+        intx_host_msi = false;
+        new_type = ASSIGNED_IRQ_INTX_HOST_INTX;
+    }
+
+    r = kvm_device_intx_assign(kvm_state, dev->dev_id, intx_host_msi,
+                               intx_route.irq);
+    if (r < 0) {
+        if (r == -EIO && !(dev->features & ASSIGNED_DEVICE_PREFER_MSI_MASK) &&
+            dev->cap.available & ASSIGNED_DEVICE_CAP_MSI) {
+            /* Retry with host-side MSI. There might be an IRQ conflict and
+             * either the kernel or the device doesn't support sharing. */
+            error_report("Host-side INTx sharing not supported, "
+                         "using MSI instead.\n"
+                         "Some devices do not to work properly in this mode.");
+            dev->features |= ASSIGNED_DEVICE_PREFER_MSI_MASK;
+            goto retry;
+        }
+        error_report("Failed to assign irq for \"%s\": %s",
+                     dev->dev.qdev.id, strerror(-r));
+        error_report("Perhaps you are assigning a device "
+                     "that shares an IRQ with another device?");
+        return r;
+    }
+
+    dev->intx_route = intx_route;
+    dev->assigned_irq_type = new_type;
+    return r;
+}
+
+static void deassign_device(AssignedDevice *dev)
+{
+    int r;
+
+    r = kvm_device_pci_deassign(kvm_state, dev->dev_id);
+    assert(r == 0);
+}
+
+/* The pci config space got updated. Check if irq numbers have changed
+ * for our devices
+ */
+static void assigned_dev_update_irq_routing(PCIDevice *dev)
+{
+    AssignedDevice *assigned_dev = DO_UPCAST(AssignedDevice, dev, dev);
+    Error *err = NULL;
+    int r;
+
+    r = assign_intx(assigned_dev);
+    if (r < 0) {
+        qdev_unplug(&dev->qdev, &err);
+        assert(!err);
+    }
+}
+
+static void assigned_dev_update_msi(PCIDevice *pci_dev)
+{
+    AssignedDevice *assigned_dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    uint8_t ctrl_byte = pci_get_byte(pci_dev->config + pci_dev->msi_cap +
+                                     PCI_MSI_FLAGS);
+    int r;
+
+    /* Some guests gratuitously disable MSI even if they're not using it,
+     * try to catch this by only deassigning irqs if the guest is using
+     * MSI or intends to start. */
+    if (assigned_dev->assigned_irq_type == ASSIGNED_IRQ_MSI ||
+        (ctrl_byte & PCI_MSI_FLAGS_ENABLE)) {
+        r = kvm_device_msi_deassign(kvm_state, assigned_dev->dev_id);
+        /* -ENXIO means no assigned irq */
+        if (r && r != -ENXIO) {
+            perror("assigned_dev_update_msi: deassign irq");
+        }
+
+        free_msi_virqs(assigned_dev);
+
+        assigned_dev->assigned_irq_type = ASSIGNED_IRQ_NONE;
+        pci_device_set_intx_routing_notifier(pci_dev, NULL);
+    }
+
+    if (ctrl_byte & PCI_MSI_FLAGS_ENABLE) {
+        uint8_t *pos = pci_dev->config + pci_dev->msi_cap;
+        MSIMessage msg;
+        int virq;
+
+        msg.address = pci_get_long(pos + PCI_MSI_ADDRESS_LO);
+        msg.data = pci_get_word(pos + PCI_MSI_DATA_32);
+        virq = kvm_irqchip_add_msi_route(kvm_state, msg);
+        if (virq < 0) {
+            perror("assigned_dev_update_msi: kvm_irqchip_add_msi_route");
+            return;
+        }
+
+        assigned_dev->msi_virq = g_malloc(sizeof(*assigned_dev->msi_virq));
+        assigned_dev->msi_virq_nr = 1;
+        assigned_dev->msi_virq[0] = virq;
+        if (kvm_device_msi_assign(kvm_state, assigned_dev->dev_id, virq) < 0) {
+            perror("assigned_dev_update_msi: kvm_device_msi_assign");
+        }
+
+        assigned_dev->intx_route.mode = PCI_INTX_DISABLED;
+        assigned_dev->intx_route.irq = -1;
+        assigned_dev->assigned_irq_type = ASSIGNED_IRQ_MSI;
+    } else {
+        assign_intx(assigned_dev);
+    }
+}
+
+static bool assigned_dev_msix_masked(MSIXTableEntry *entry)
+{
+    return (entry->ctrl & cpu_to_le32(0x1)) != 0;
+}
+
+static int assigned_dev_update_msix_mmio(PCIDevice *pci_dev)
+{
+    AssignedDevice *adev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    uint16_t entries_nr = 0;
+    int i, r = 0;
+    MSIXTableEntry *entry = adev->msix_table;
+    MSIMessage msg;
+
+    /* Get the usable entry number for allocating */
+    for (i = 0; i < adev->msix_max; i++, entry++) {
+        if (assigned_dev_msix_masked(entry)) {
+            continue;
+        }
+        entries_nr++;
+    }
+
+    DEBUG("MSI-X entries: %d\n", entries_nr);
+
+    /* It's valid to enable MSI-X with all entries masked */
+    if (!entries_nr) {
+        return 0;
+    }
+
+    r = kvm_device_msix_init_vectors(kvm_state, adev->dev_id, entries_nr);
+    if (r != 0) {
+        error_report("fail to set MSI-X entry number for MSIX! %s",
+                     strerror(-r));
+        return r;
+    }
+
+    free_msi_virqs(adev);
+
+    adev->msi_virq_nr = adev->msix_max;
+    adev->msi_virq = g_malloc(adev->msix_max * sizeof(*adev->msi_virq));
+
+    entry = adev->msix_table;
+    for (i = 0; i < adev->msix_max; i++, entry++) {
+        adev->msi_virq[i] = -1;
+
+        if (assigned_dev_msix_masked(entry)) {
+            continue;
+        }
+
+        msg.address = entry->addr_lo | ((uint64_t)entry->addr_hi << 32);
+        msg.data = entry->data;
+        r = kvm_irqchip_add_msi_route(kvm_state, msg);
+        if (r < 0) {
+            return r;
+        }
+        adev->msi_virq[i] = r;
+
+        DEBUG("MSI-X vector %d, gsi %d, addr %08x_%08x, data %08x\n", i,
+              r, entry->addr_hi, entry->addr_lo, entry->data);
+
+        r = kvm_device_msix_set_vector(kvm_state, adev->dev_id, i,
+                                       adev->msi_virq[i]);
+        if (r) {
+            error_report("fail to set MSI-X entry! %s", strerror(-r));
+            break;
+        }
+    }
+
+    return r;
+}
+
+static void assigned_dev_update_msix(PCIDevice *pci_dev)
+{
+    AssignedDevice *assigned_dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    uint16_t ctrl_word = pci_get_word(pci_dev->config + pci_dev->msix_cap +
+                                      PCI_MSIX_FLAGS);
+    int r;
+
+    /* Some guests gratuitously disable MSIX even if they're not using it,
+     * try to catch this by only deassigning irqs if the guest is using
+     * MSIX or intends to start. */
+    if ((assigned_dev->assigned_irq_type == ASSIGNED_IRQ_MSIX) ||
+        (ctrl_word & PCI_MSIX_FLAGS_ENABLE)) {
+        r = kvm_device_msix_deassign(kvm_state, assigned_dev->dev_id);
+        /* -ENXIO means no assigned irq */
+        if (r && r != -ENXIO) {
+            perror("assigned_dev_update_msix: deassign irq");
+        }
+
+        free_msi_virqs(assigned_dev);
+
+        assigned_dev->assigned_irq_type = ASSIGNED_IRQ_NONE;
+        pci_device_set_intx_routing_notifier(pci_dev, NULL);
+    }
+
+    if (ctrl_word & PCI_MSIX_FLAGS_ENABLE) {
+        if (assigned_dev_update_msix_mmio(pci_dev) < 0) {
+            perror("assigned_dev_update_msix_mmio");
+            return;
+        }
+
+        if (assigned_dev->msi_virq_nr > 0) {
+            if (kvm_device_msix_assign(kvm_state, assigned_dev->dev_id) < 0) {
+                perror("assigned_dev_enable_msix: assign irq");
+                return;
+            }
+        }
+        assigned_dev->intx_route.mode = PCI_INTX_DISABLED;
+        assigned_dev->intx_route.irq = -1;
+        assigned_dev->assigned_irq_type = ASSIGNED_IRQ_MSIX;
+    } else {
+        assign_intx(assigned_dev);
+    }
+}
+
+static uint32_t assigned_dev_pci_read_config(PCIDevice *pci_dev,
+                                             uint32_t address, int len)
+{
+    AssignedDevice *assigned_dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    uint32_t virt_val = pci_default_read_config(pci_dev, address, len);
+    uint32_t real_val, emulate_mask, full_emulation_mask;
+
+    emulate_mask = 0;
+    memcpy(&emulate_mask, assigned_dev->emulate_config_read + address, len);
+    emulate_mask = le32_to_cpu(emulate_mask);
+
+    full_emulation_mask = 0xffffffff >> (32 - len * 8);
+
+    if (emulate_mask != full_emulation_mask) {
+        real_val = assigned_dev_pci_read(pci_dev, address, len);
+        return (virt_val & emulate_mask) | (real_val & ~emulate_mask);
+    } else {
+        return virt_val;
+    }
+}
+
+static void assigned_dev_pci_write_config(PCIDevice *pci_dev, uint32_t address,
+                                          uint32_t val, int len)
+{
+    AssignedDevice *assigned_dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    uint16_t old_cmd = pci_get_word(pci_dev->config + PCI_COMMAND);
+    uint32_t emulate_mask, full_emulation_mask;
+    int ret;
+
+    pci_default_write_config(pci_dev, address, val, len);
+
+    if (kvm_has_intx_set_mask() &&
+        range_covers_byte(address, len, PCI_COMMAND + 1)) {
+        bool intx_masked = (pci_get_word(pci_dev->config + PCI_COMMAND) &
+                            PCI_COMMAND_INTX_DISABLE);
+
+        if (intx_masked != !!(old_cmd & PCI_COMMAND_INTX_DISABLE)) {
+            ret = kvm_device_intx_set_mask(kvm_state, assigned_dev->dev_id,
+                                           intx_masked);
+            if (ret) {
+                perror("assigned_dev_pci_write_config: set intx mask");
+            }
+        }
+    }
+    if (assigned_dev->cap.available & ASSIGNED_DEVICE_CAP_MSI) {
+        if (range_covers_byte(address, len,
+                              pci_dev->msi_cap + PCI_MSI_FLAGS)) {
+            assigned_dev_update_msi(pci_dev);
+        }
+    }
+    if (assigned_dev->cap.available & ASSIGNED_DEVICE_CAP_MSIX) {
+        if (range_covers_byte(address, len,
+                              pci_dev->msix_cap + PCI_MSIX_FLAGS + 1)) {
+            assigned_dev_update_msix(pci_dev);
+        }
+    }
+
+    emulate_mask = 0;
+    memcpy(&emulate_mask, assigned_dev->emulate_config_write + address, len);
+    emulate_mask = le32_to_cpu(emulate_mask);
+
+    full_emulation_mask = 0xffffffff >> (32 - len * 8);
+
+    if (emulate_mask != full_emulation_mask) {
+        if (emulate_mask) {
+            val &= ~emulate_mask;
+            val |= assigned_dev_pci_read(pci_dev, address, len) & emulate_mask;
+        }
+        assigned_dev_pci_write(pci_dev, address, val, len);
+    }
+}
+
+static void assigned_dev_setup_cap_read(AssignedDevice *dev, uint32_t offset,
+                                        uint32_t len)
+{
+    assigned_dev_direct_config_read(dev, offset, len);
+    assigned_dev_emulate_config_read(dev, offset + PCI_CAP_LIST_NEXT, 1);
+}
+
+static int assigned_device_pci_cap_init(PCIDevice *pci_dev)
+{
+    AssignedDevice *dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    PCIRegion *pci_region = dev->real_device.regions;
+    int ret, pos;
+
+    /* Clear initial capabilities pointer and status copied from hw */
+    pci_set_byte(pci_dev->config + PCI_CAPABILITY_LIST, 0);
+    pci_set_word(pci_dev->config + PCI_STATUS,
+                 pci_get_word(pci_dev->config + PCI_STATUS) &
+                 ~PCI_STATUS_CAP_LIST);
+
+    /* Expose MSI capability
+     * MSI capability is the 1st capability in capability config */
+    pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_MSI, 0);
+    if (pos != 0 && kvm_check_extension(kvm_state, KVM_CAP_ASSIGN_DEV_IRQ)) {
+        if (!check_irqchip_in_kernel()) {
+            return -ENOTSUP;
+        }
+        dev->cap.available |= ASSIGNED_DEVICE_CAP_MSI;
+        /* Only 32-bit/no-mask currently supported */
+        ret = pci_add_capability(pci_dev, PCI_CAP_ID_MSI, pos, 10);
+        if (ret < 0) {
+            return ret;
+        }
+        pci_dev->msi_cap = pos;
+
+        pci_set_word(pci_dev->config + pos + PCI_MSI_FLAGS,
+                     pci_get_word(pci_dev->config + pos + PCI_MSI_FLAGS) &
+                     PCI_MSI_FLAGS_QMASK);
+        pci_set_long(pci_dev->config + pos + PCI_MSI_ADDRESS_LO, 0);
+        pci_set_word(pci_dev->config + pos + PCI_MSI_DATA_32, 0);
+
+        /* Set writable fields */
+        pci_set_word(pci_dev->wmask + pos + PCI_MSI_FLAGS,
+                     PCI_MSI_FLAGS_QSIZE | PCI_MSI_FLAGS_ENABLE);
+        pci_set_long(pci_dev->wmask + pos + PCI_MSI_ADDRESS_LO, 0xfffffffc);
+        pci_set_word(pci_dev->wmask + pos + PCI_MSI_DATA_32, 0xffff);
+    }
+    /* Expose MSI-X capability */
+    pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_MSIX, 0);
+    if (pos != 0 && kvm_device_msix_supported(kvm_state)) {
+        int bar_nr;
+        uint32_t msix_table_entry;
+
+        if (!check_irqchip_in_kernel()) {
+            return -ENOTSUP;
+        }
+        dev->cap.available |= ASSIGNED_DEVICE_CAP_MSIX;
+        ret = pci_add_capability(pci_dev, PCI_CAP_ID_MSIX, pos, 12);
+        if (ret < 0) {
+            return ret;
+        }
+        pci_dev->msix_cap = pos;
+
+        pci_set_word(pci_dev->config + pos + PCI_MSIX_FLAGS,
+                     pci_get_word(pci_dev->config + pos + PCI_MSIX_FLAGS) &
+                     PCI_MSIX_FLAGS_QSIZE);
+
+        /* Only enable and function mask bits are writable */
+        pci_set_word(pci_dev->wmask + pos + PCI_MSIX_FLAGS,
+                     PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL);
+
+        msix_table_entry = pci_get_long(pci_dev->config + pos + PCI_MSIX_TABLE);
+        bar_nr = msix_table_entry & PCI_MSIX_FLAGS_BIRMASK;
+        msix_table_entry &= ~PCI_MSIX_FLAGS_BIRMASK;
+        dev->msix_table_addr = pci_region[bar_nr].base_addr + msix_table_entry;
+        dev->msix_max = pci_get_word(pci_dev->config + pos + PCI_MSIX_FLAGS);
+        dev->msix_max &= PCI_MSIX_FLAGS_QSIZE;
+        dev->msix_max += 1;
+    }
+
+    /* Minimal PM support, nothing writable, device appears to NAK changes */
+    pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_PM, 0);
+    if (pos) {
+        uint16_t pmc;
+
+        ret = pci_add_capability(pci_dev, PCI_CAP_ID_PM, pos, PCI_PM_SIZEOF);
+        if (ret < 0) {
+            return ret;
+        }
+
+        assigned_dev_setup_cap_read(dev, pos, PCI_PM_SIZEOF);
+
+        pmc = pci_get_word(pci_dev->config + pos + PCI_CAP_FLAGS);
+        pmc &= (PCI_PM_CAP_VER_MASK | PCI_PM_CAP_DSI);
+        pci_set_word(pci_dev->config + pos + PCI_CAP_FLAGS, pmc);
+
+        /* assign_device will bring the device up to D0, so we don't need
+         * to worry about doing that ourselves here. */
+        pci_set_word(pci_dev->config + pos + PCI_PM_CTRL,
+                     PCI_PM_CTRL_NO_SOFT_RESET);
+
+        pci_set_byte(pci_dev->config + pos + PCI_PM_PPB_EXTENSIONS, 0);
+        pci_set_byte(pci_dev->config + pos + PCI_PM_DATA_REGISTER, 0);
+    }
+
+    pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_EXP, 0);
+    if (pos) {
+        uint8_t version, size = 0;
+        uint16_t type, devctl, lnksta;
+        uint32_t devcap, lnkcap;
+
+        version = pci_get_byte(pci_dev->config + pos + PCI_EXP_FLAGS);
+        version &= PCI_EXP_FLAGS_VERS;
+        if (version == 1) {
+            size = 0x14;
+        } else if (version == 2) {
+            /*
+             * Check for non-std size, accept reduced size to 0x34,
+             * which is what bcm5761 implemented, violating the
+             * PCIe v3.0 spec that regs should exist and be read as 0,
+             * not optionally provided and shorten the struct size.
+             */
+            size = MIN(0x3c, PCI_CONFIG_SPACE_SIZE - pos);
+            if (size < 0x34) {
+                error_report("%s: Invalid size PCIe cap-id 0x%x",
+                             __func__, PCI_CAP_ID_EXP);
+                return -EINVAL;
+            } else if (size != 0x3c) {
+                error_report("WARNING, %s: PCIe cap-id 0x%x has "
+                             "non-standard size 0x%x; std size should be 0x3c",
+                             __func__, PCI_CAP_ID_EXP, size);
+            }
+        } else if (version == 0) {
+            uint16_t vid, did;
+            vid = pci_get_word(pci_dev->config + PCI_VENDOR_ID);
+            did = pci_get_word(pci_dev->config + PCI_DEVICE_ID);
+            if (vid == PCI_VENDOR_ID_INTEL && did == 0x10ed) {
+                /*
+                 * quirk for Intel 82599 VF with invalid PCIe capability
+                 * version, should really be version 2 (same as PF)
+                 */
+                size = 0x3c;
+            }
+        }
+
+        if (size == 0) {
+            error_report("%s: Unsupported PCI express capability version %d",
+                         __func__, version);
+            return -EINVAL;
+        }
+
+        ret = pci_add_capability(pci_dev, PCI_CAP_ID_EXP, pos, size);
+        if (ret < 0) {
+            return ret;
+        }
+
+        assigned_dev_setup_cap_read(dev, pos, size);
+
+        type = pci_get_word(pci_dev->config + pos + PCI_EXP_FLAGS);
+        type = (type & PCI_EXP_FLAGS_TYPE) >> 4;
+        if (type != PCI_EXP_TYPE_ENDPOINT &&
+            type != PCI_EXP_TYPE_LEG_END && type != PCI_EXP_TYPE_RC_END) {
+            error_report("Device assignment only supports endpoint assignment,"
+                         " device type %d", type);
+            return -EINVAL;
+        }
+
+        /* capabilities, pass existing read-only copy
+         * PCI_EXP_FLAGS_IRQ: updated by hardware, should be direct read */
+
+        /* device capabilities: hide FLR */
+        devcap = pci_get_long(pci_dev->config + pos + PCI_EXP_DEVCAP);
+        devcap &= ~PCI_EXP_DEVCAP_FLR;
+        pci_set_long(pci_dev->config + pos + PCI_EXP_DEVCAP, devcap);
+
+        /* device control: clear all error reporting enable bits, leaving
+         *                 only a few host values.  Note, these are
+         *                 all writable, but not passed to hw.
+         */
+        devctl = pci_get_word(pci_dev->config + pos + PCI_EXP_DEVCTL);
+        devctl = (devctl & (PCI_EXP_DEVCTL_READRQ | PCI_EXP_DEVCTL_PAYLOAD)) |
+                  PCI_EXP_DEVCTL_RELAX_EN | PCI_EXP_DEVCTL_NOSNOOP_EN;
+        pci_set_word(pci_dev->config + pos + PCI_EXP_DEVCTL, devctl);
+        devctl = PCI_EXP_DEVCTL_BCR_FLR | PCI_EXP_DEVCTL_AUX_PME;
+        pci_set_word(pci_dev->wmask + pos + PCI_EXP_DEVCTL, ~devctl);
+
+        /* Clear device status */
+        pci_set_word(pci_dev->config + pos + PCI_EXP_DEVSTA, 0);
+
+        /* Link capabilities, expose links and latencues, clear reporting */
+        lnkcap = pci_get_long(pci_dev->config + pos + PCI_EXP_LNKCAP);
+        lnkcap &= (PCI_EXP_LNKCAP_SLS | PCI_EXP_LNKCAP_MLW |
+                   PCI_EXP_LNKCAP_ASPMS | PCI_EXP_LNKCAP_L0SEL |
+                   PCI_EXP_LNKCAP_L1EL);
+        pci_set_long(pci_dev->config + pos + PCI_EXP_LNKCAP, lnkcap);
+
+        /* Link control, pass existing read-only copy.  Should be writable? */
+
+        /* Link status, only expose current speed and width */
+        lnksta = pci_get_word(pci_dev->config + pos + PCI_EXP_LNKSTA);
+        lnksta &= (PCI_EXP_LNKSTA_CLS | PCI_EXP_LNKSTA_NLW);
+        pci_set_word(pci_dev->config + pos + PCI_EXP_LNKSTA, lnksta);
+
+        if (version >= 2) {
+            /* Slot capabilities, control, status - not needed for endpoints */
+            pci_set_long(pci_dev->config + pos + PCI_EXP_SLTCAP, 0);
+            pci_set_word(pci_dev->config + pos + PCI_EXP_SLTCTL, 0);
+            pci_set_word(pci_dev->config + pos + PCI_EXP_SLTSTA, 0);
+
+            /* Root control, capabilities, status - not needed for endpoints */
+            pci_set_word(pci_dev->config + pos + PCI_EXP_RTCTL, 0);
+            pci_set_word(pci_dev->config + pos + PCI_EXP_RTCAP, 0);
+            pci_set_long(pci_dev->config + pos + PCI_EXP_RTSTA, 0);
+
+            /* Device capabilities/control 2, pass existing read-only copy */
+            /* Link control 2, pass existing read-only copy */
+        }
+    }
+
+    pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_PCIX, 0);
+    if (pos) {
+        uint16_t cmd;
+        uint32_t status;
+
+        /* Only expose the minimum, 8 byte capability */
+        ret = pci_add_capability(pci_dev, PCI_CAP_ID_PCIX, pos, 8);
+        if (ret < 0) {
+            return ret;
+        }
+
+        assigned_dev_setup_cap_read(dev, pos, 8);
+
+        /* Command register, clear upper bits, including extended modes */
+        cmd = pci_get_word(pci_dev->config + pos + PCI_X_CMD);
+        cmd &= (PCI_X_CMD_DPERR_E | PCI_X_CMD_ERO | PCI_X_CMD_MAX_READ |
+                PCI_X_CMD_MAX_SPLIT);
+        pci_set_word(pci_dev->config + pos + PCI_X_CMD, cmd);
+
+        /* Status register, update with emulated PCI bus location, clear
+         * error bits, leave the rest. */
+        status = pci_get_long(pci_dev->config + pos + PCI_X_STATUS);
+        status &= ~(PCI_X_STATUS_BUS | PCI_X_STATUS_DEVFN);
+        status |= (pci_bus_num(pci_dev->bus) << 8) | pci_dev->devfn;
+        status &= ~(PCI_X_STATUS_SPL_DISC | PCI_X_STATUS_UNX_SPL |
+                    PCI_X_STATUS_SPL_ERR);
+        pci_set_long(pci_dev->config + pos + PCI_X_STATUS, status);
+    }
+
+    pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_VPD, 0);
+    if (pos) {
+        /* Direct R/W passthrough */
+        ret = pci_add_capability(pci_dev, PCI_CAP_ID_VPD, pos, 8);
+        if (ret < 0) {
+            return ret;
+        }
+
+        assigned_dev_setup_cap_read(dev, pos, 8);
+
+        /* direct write for cap content */
+        assigned_dev_direct_config_write(dev, pos + 2, 6);
+    }
+
+    /* Devices can have multiple vendor capabilities, get them all */
+    for (pos = 0; (pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_VNDR, pos));
+        pos += PCI_CAP_LIST_NEXT) {
+        uint8_t len = pci_get_byte(pci_dev->config + pos + PCI_CAP_FLAGS);
+        /* Direct R/W passthrough */
+        ret = pci_add_capability(pci_dev, PCI_CAP_ID_VNDR, pos, len);
+        if (ret < 0) {
+            return ret;
+        }
+
+        assigned_dev_setup_cap_read(dev, pos, len);
+
+        /* direct write for cap content */
+        assigned_dev_direct_config_write(dev, pos + 2, len - 2);
+    }
+
+    /* If real and virtual capability list status bits differ, virtualize the
+     * access. */
+    if ((pci_get_word(pci_dev->config + PCI_STATUS) & PCI_STATUS_CAP_LIST) !=
+        (assigned_dev_pci_read_byte(pci_dev, PCI_STATUS) &
+         PCI_STATUS_CAP_LIST)) {
+        dev->emulate_config_read[PCI_STATUS] |= PCI_STATUS_CAP_LIST;
+    }
+
+    return 0;
+}
+
+static uint64_t
+assigned_dev_msix_mmio_read(void *opaque, target_phys_addr_t addr,
+                            unsigned size)
+{
+    AssignedDevice *adev = opaque;
+    uint64_t val;
+
+    memcpy(&val, (void *)((uint8_t *)adev->msix_table + addr), size);
+
+    return val;
+}
+
+static void assigned_dev_msix_mmio_write(void *opaque, target_phys_addr_t addr,
+                                         uint64_t val, unsigned size)
+{
+    AssignedDevice *adev = opaque;
+    PCIDevice *pdev = &adev->dev;
+    uint16_t ctrl;
+    MSIXTableEntry orig;
+    int i = addr >> 4;
+
+    if (i >= adev->msix_max) {
+        return; /* Drop write */
+    }
+
+    ctrl = pci_get_word(pdev->config + pdev->msix_cap + PCI_MSIX_FLAGS);
+
+    DEBUG("write to MSI-X table offset 0x%lx, val 0x%lx\n", addr, val);
+
+    if (ctrl & PCI_MSIX_FLAGS_ENABLE) {
+        orig = adev->msix_table[i];
+    }
+
+    memcpy((uint8_t *)adev->msix_table + addr, &val, size);
+
+    if (ctrl & PCI_MSIX_FLAGS_ENABLE) {
+        MSIXTableEntry *entry = &adev->msix_table[i];
+
+        if (!assigned_dev_msix_masked(&orig) &&
+            assigned_dev_msix_masked(entry)) {
+            /*
+             * Vector masked, disable it
+             *
+             * XXX It's not clear if we can or should actually attempt
+             * to mask or disable the interrupt.  KVM doesn't have
+             * support for pending bits and kvm_assign_set_msix_entry
+             * doesn't modify the device hardware mask.  Interrupts
+             * while masked are simply not injected to the guest, so
+             * are lost.  Can we get away with always injecting an
+             * interrupt on unmask?
+             */
+        } else if (assigned_dev_msix_masked(&orig) &&
+                   !assigned_dev_msix_masked(entry)) {
+            /* Vector unmasked */
+            if (i >= adev->msi_virq_nr || adev->msi_virq[i] < 0) {
+                /* Previously unassigned vector, start from scratch */
+                assigned_dev_update_msix(pdev);
+                return;
+            } else {
+                /* Update an existing, previously masked vector */
+                MSIMessage msg;
+                int ret;
+
+                msg.address = entry->addr_lo |
+                    ((uint64_t)entry->addr_hi << 32);
+                msg.data = entry->data;
+
+                ret = kvm_irqchip_update_msi_route(kvm_state,
+                                                   adev->msi_virq[i], msg);
+                if (ret) {
+                    error_report("Error updating irq routing entry (%d)", ret);
+                }
+            }
+        }
+    }
+}
+
+static const MemoryRegionOps assigned_dev_msix_mmio_ops = {
+    .read = assigned_dev_msix_mmio_read,
+    .write = assigned_dev_msix_mmio_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    },
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    },
+};
+
+static void assigned_dev_msix_reset(AssignedDevice *dev)
+{
+    MSIXTableEntry *entry;
+    int i;
+
+    if (!dev->msix_table) {
+        return;
+    }
+
+    memset(dev->msix_table, 0, MSIX_PAGE_SIZE);
+
+    for (i = 0, entry = dev->msix_table; i < dev->msix_max; i++, entry++) {
+        entry->ctrl = cpu_to_le32(0x1); /* Masked */
+    }
+}
+
+static int assigned_dev_register_msix_mmio(AssignedDevice *dev)
+{
+    dev->msix_table = mmap(NULL, MSIX_PAGE_SIZE, PROT_READ|PROT_WRITE,
+                           MAP_ANONYMOUS|MAP_PRIVATE, 0, 0);
+    if (dev->msix_table == MAP_FAILED) {
+        error_report("fail allocate msix_table! %s", strerror(errno));
+        return -EFAULT;
+    }
+
+    assigned_dev_msix_reset(dev);
+
+    memory_region_init_io(&dev->mmio, &assigned_dev_msix_mmio_ops, dev,
+                          "assigned-dev-msix", MSIX_PAGE_SIZE);
+    return 0;
+}
+
+static void assigned_dev_unregister_msix_mmio(AssignedDevice *dev)
+{
+    if (!dev->msix_table) {
+        return;
+    }
+
+    memory_region_destroy(&dev->mmio);
+
+    if (munmap(dev->msix_table, MSIX_PAGE_SIZE) == -1) {
+        error_report("error unmapping msix_table! %s", strerror(errno));
+    }
+    dev->msix_table = NULL;
+}
+
+static const VMStateDescription vmstate_assigned_device = {
+    .name = "pci-assign",
+    .unmigratable = 1,
+};
+
+static void reset_assigned_device(DeviceState *dev)
+{
+    PCIDevice *pci_dev = DO_UPCAST(PCIDevice, qdev, dev);
+    AssignedDevice *adev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    char reset_file[64];
+    const char reset[] = "1";
+    int fd, ret;
+
+    /*
+     * If a guest is reset without being shutdown, MSI/MSI-X can still
+     * be running.  We want to return the device to a known state on
+     * reset, so disable those here.  We especially do not want MSI-X
+     * enabled since it lives in MMIO space, which is about to get
+     * disabled.
+     */
+    if (adev->assigned_irq_type == ASSIGNED_IRQ_MSIX) {
+        uint16_t ctrl = pci_get_word(pci_dev->config +
+                                     pci_dev->msix_cap + PCI_MSIX_FLAGS);
+
+        pci_set_word(pci_dev->config + pci_dev->msix_cap + PCI_MSIX_FLAGS,
+                     ctrl & ~PCI_MSIX_FLAGS_ENABLE);
+        assigned_dev_update_msix(pci_dev);
+    } else if (adev->assigned_irq_type == ASSIGNED_IRQ_MSI) {
+        uint8_t ctrl = pci_get_byte(pci_dev->config +
+                                    pci_dev->msi_cap + PCI_MSI_FLAGS);
+
+        pci_set_byte(pci_dev->config + pci_dev->msi_cap + PCI_MSI_FLAGS,
+                     ctrl & ~PCI_MSI_FLAGS_ENABLE);
+        assigned_dev_update_msi(pci_dev);
+    }
+
+    snprintf(reset_file, sizeof(reset_file),
+             "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/reset",
+             adev->host.domain, adev->host.bus, adev->host.slot,
+             adev->host.function);
+
+    /*
+     * Issue a device reset via pci-sysfs.  Note that we use write(2) here
+     * and ignore the return value because some kernels have a bug that
+     * returns 0 rather than bytes written on success, sending us into an
+     * infinite retry loop using other write mechanisms.
+     */
+    fd = open(reset_file, O_WRONLY);
+    if (fd != -1) {
+        ret = write(fd, reset, strlen(reset));
+        (void)ret;
+        close(fd);
+    }
+
+    /*
+     * When a 0 is written to the bus master register, the device is logically
+     * disconnected from the PCI bus. This avoids further DMA transfers.
+     */
+    assigned_dev_pci_write_config(pci_dev, PCI_COMMAND, 0, 1);
+}
+
+static int assigned_initfn(struct PCIDevice *pci_dev)
+{
+    AssignedDevice *dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+    uint8_t e_intx;
+    int r;
+
+    if (!kvm_enabled()) {
+        error_report("pci-assign: error: requires KVM support");
+        return -1;
+    }
+
+    if (!dev->host.domain && !dev->host.bus && !dev->host.slot &&
+        !dev->host.function) {
+        error_report("pci-assign: error: no host device specified");
+        return -1;
+    }
+
+    /*
+     * Set up basic config space access control. Will be further refined during
+     * device initialization.
+     */
+    assigned_dev_emulate_config_read(dev, 0, PCI_CONFIG_SPACE_SIZE);
+    assigned_dev_direct_config_read(dev, PCI_STATUS, 2);
+    assigned_dev_direct_config_read(dev, PCI_REVISION_ID, 1);
+    assigned_dev_direct_config_read(dev, PCI_CLASS_PROG, 3);
+    assigned_dev_direct_config_read(dev, PCI_CACHE_LINE_SIZE, 1);
+    assigned_dev_direct_config_read(dev, PCI_LATENCY_TIMER, 1);
+    assigned_dev_direct_config_read(dev, PCI_BIST, 1);
+    assigned_dev_direct_config_read(dev, PCI_CARDBUS_CIS, 4);
+    assigned_dev_direct_config_read(dev, PCI_SUBSYSTEM_VENDOR_ID, 2);
+    assigned_dev_direct_config_read(dev, PCI_SUBSYSTEM_ID, 2);
+    assigned_dev_direct_config_read(dev, PCI_CAPABILITY_LIST + 1, 7);
+    assigned_dev_direct_config_read(dev, PCI_MIN_GNT, 1);
+    assigned_dev_direct_config_read(dev, PCI_MAX_LAT, 1);
+    memcpy(dev->emulate_config_write, dev->emulate_config_read,
+           sizeof(dev->emulate_config_read));
+
+    if (get_real_device(dev, dev->host.domain, dev->host.bus,
+                        dev->host.slot, dev->host.function)) {
+        error_report("pci-assign: Error: Couldn't get real device (%s)!",
+                     dev->dev.qdev.id);
+        goto out;
+    }
+
+    if (assigned_device_pci_cap_init(pci_dev) < 0) {
+        goto out;
+    }
+
+    /* intercept MSI-X entry page in the MMIO */
+    if (dev->cap.available & ASSIGNED_DEVICE_CAP_MSIX) {
+        if (assigned_dev_register_msix_mmio(dev)) {
+            goto out;
+        }
+    }
+
+    /* handle real device's MMIO/PIO BARs */
+    if (assigned_dev_register_regions(dev->real_device.regions,
+                                      dev->real_device.region_number,
+                                      dev)) {
+        goto out;
+    }
+
+    /* handle interrupt routing */
+    e_intx = dev->dev.config[PCI_INTERRUPT_PIN] - 1;
+    dev->intpin = e_intx;
+    dev->intx_route.mode = PCI_INTX_DISABLED;
+    dev->intx_route.irq = -1;
+
+    /* assign device to guest */
+    r = assign_device(dev);
+    if (r < 0) {
+        goto out;
+    }
+
+    /* assign legacy INTx to the device */
+    r = assign_intx(dev);
+    if (r < 0) {
+        goto assigned_out;
+    }
+
+    assigned_dev_load_option_rom(dev);
+
+    add_boot_device_path(dev->bootindex, &pci_dev->qdev, NULL);
+
+    return 0;
+
+assigned_out:
+    deassign_device(dev);
+out:
+    free_assigned_device(dev);
+    return -1;
+}
+
+static void assigned_exitfn(struct PCIDevice *pci_dev)
+{
+    AssignedDevice *dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
+
+    deassign_device(dev);
+    free_assigned_device(dev);
+}
+
+static Property assigned_dev_properties[] = {
+    DEFINE_PROP_PCI_HOST_DEVADDR("host", AssignedDevice, host),
+    DEFINE_PROP_BIT("prefer_msi", AssignedDevice, features,
+                    ASSIGNED_DEVICE_PREFER_MSI_BIT, false),
+    DEFINE_PROP_BIT("share_intx", AssignedDevice, features,
+                    ASSIGNED_DEVICE_SHARE_INTX_BIT, true),
+    DEFINE_PROP_INT32("bootindex", AssignedDevice, bootindex, -1),
+    DEFINE_PROP_STRING("configfd", AssignedDevice, configfd_name),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void assign_class_init(ObjectClass *klass, void *data)
+{
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    k->init         = assigned_initfn;
+    k->exit         = assigned_exitfn;
+    k->config_read  = assigned_dev_pci_read_config;
+    k->config_write = assigned_dev_pci_write_config;
+    dc->props       = assigned_dev_properties;
+    dc->vmsd        = &vmstate_assigned_device;
+    dc->reset       = reset_assigned_device;
+    dc->desc        = "KVM-based PCI passthrough";
+}
+
+static const TypeInfo assign_info = {
+    .name               = "kvm-pci-assign",
+    .parent             = TYPE_PCI_DEVICE,
+    .instance_size      = sizeof(AssignedDevice),
+    .class_init         = assign_class_init,
+};
+
+static void assign_register_types(void)
+{
+    type_register_static(&assign_info);
+}
+
+type_init(assign_register_types)
+
+/*
+ * Scan the assigned devices for the devices that have an option ROM, and then
+ * load the corresponding ROM data to RAM. If an error occurs while loading an
+ * option ROM, we just ignore that option ROM and continue with the next one.
+ */
+static void assigned_dev_load_option_rom(AssignedDevice *dev)
+{
+    char name[32], rom_file[64];
+    FILE *fp;
+    uint8_t val;
+    struct stat st;
+    void *ptr;
+
+    /* If loading ROM from file, pci handles it */
+    if (dev->dev.romfile || !dev->dev.rom_bar) {
+        return;
+    }
+
+    snprintf(rom_file, sizeof(rom_file),
+             "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/rom",
+             dev->host.domain, dev->host.bus, dev->host.slot,
+             dev->host.function);
+
+    if (stat(rom_file, &st)) {
+        return;
+    }
+
+    if (access(rom_file, F_OK)) {
+        error_report("pci-assign: Insufficient privileges for %s", rom_file);
+        return;
+    }
+
+    /* Write "1" to the ROM file to enable it */
+    fp = fopen(rom_file, "r+");
+    if (fp == NULL) {
+        return;
+    }
+    val = 1;
+    if (fwrite(&val, 1, 1, fp) != 1) {
+        goto close_rom;
+    }
+    fseek(fp, 0, SEEK_SET);
+
+    snprintf(name, sizeof(name), "%s.rom",
+            object_get_typename(OBJECT(dev)));
+    memory_region_init_ram(&dev->dev.rom, name, st.st_size);
+    vmstate_register_ram(&dev->dev.rom, &dev->dev.qdev);
+    ptr = memory_region_get_ram_ptr(&dev->dev.rom);
+    memset(ptr, 0xff, st.st_size);
+
+    if (!fread(ptr, 1, st.st_size, fp)) {
+        error_report("pci-assign: Cannot read from host %s\n"
+                     "\tDevice option ROM contents are probably invalid "
+                     "(check dmesg).\n\tSkip option ROM probe with rombar=0, "
+                     "or load from file with romfile=", rom_file);
+        memory_region_destroy(&dev->dev.rom);
+        goto close_rom;
+    }
+
+    pci_register_bar(&dev->dev, PCI_ROM_SLOT, 0, &dev->dev.rom);
+    dev->dev.has_rom = true;
+close_rom:
+    /* Write "0" to disable ROM */
+    fseek(fp, 0, SEEK_SET);
+    val = 0;
+    if (!fwrite(&val, 1, 1, fp)) {
+        DEBUG("%s\n", "Failed to disable pci-sysfs rom file");
+    }
+    fclose(fp);
+}
diff --git a/hw/qdev-monitor.c b/hw/qdev-monitor.c
index 018b386..4b34871 100644
--- a/hw/qdev-monitor.c
+++ b/hw/qdev-monitor.c
@@ -44,6 +44,7 @@  static const QDevAlias qdev_alias_table[] = {
     { "virtio-serial-s390", "virtio-serial", QEMU_ARCH_S390X },
     { "lsi53c895a", "lsi" },
     { "ich9-ahci", "ahci" },
+    { "kvm-pci-assign", "pci-assign" },
     { }
 };