[v4,16/16] libqos: add VIRTIO PCI 1.0 support
diff mbox series

Message ID 20191023100425.12168-17-stefanha@redhat.com
State New
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Series
  • libqos: add VIRTIO PCI 1.0 support
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Commit Message

Stefan Hajnoczi Oct. 23, 2019, 10:04 a.m. UTC
Implement the VIRTIO 1.0 virtio-pci interface.  The main change here is
that the register layout is no longer a fixed layout in BAR 0.  Instead
we have to iterate of PCI Capabilities to find descriptions of where
various registers are located.  The vring registers are also more
fine-grained, allowing for more flexible vring layouts, but we don't
take advantage of that.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
---
 tests/Makefile.include           |   1 +
 tests/libqos/virtio-pci-modern.h |  17 ++
 tests/libqos/virtio-pci.h        |  10 +
 tests/libqos/virtio-pci-modern.c | 443 +++++++++++++++++++++++++++++++
 tests/libqos/virtio-pci.c        |   6 +-
 5 files changed, 476 insertions(+), 1 deletion(-)
 create mode 100644 tests/libqos/virtio-pci-modern.h
 create mode 100644 tests/libqos/virtio-pci-modern.c

Comments

Thomas Huth Oct. 23, 2019, 11:22 a.m. UTC | #1
----- Original Message -----
> From: "Stefan Hajnoczi" <stefanha@redhat.com>
> Sent: Wednesday, October 23, 2019 12:04:25 PM
> 
> Implement the VIRTIO 1.0 virtio-pci interface.  The main change here is
> that the register layout is no longer a fixed layout in BAR 0.  Instead
> we have to iterate of PCI Capabilities to find descriptions of where
> various registers are located.  The vring registers are also more
> fine-grained, allowing for more flexible vring layouts, but we don't
> take advantage of that.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: Sergio Lopez <slp@redhat.com>
> ---
>  tests/Makefile.include           |   1 +
>  tests/libqos/virtio-pci-modern.h |  17 ++
>  tests/libqos/virtio-pci.h        |  10 +
>  tests/libqos/virtio-pci-modern.c | 443 +++++++++++++++++++++++++++++++
>  tests/libqos/virtio-pci.c        |   6 +-
>  5 files changed, 476 insertions(+), 1 deletion(-)
>  create mode 100644 tests/libqos/virtio-pci-modern.h
>  create mode 100644 tests/libqos/virtio-pci-modern.c

Acked-by: Thomas Huth <thuth@redhat.com>

Patch
diff mbox series

diff --git a/tests/Makefile.include b/tests/Makefile.include
index 3543451ed3..3f633c8313 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -715,6 +715,7 @@  qos-test-obj-y += tests/libqos/virtio-blk.o
 qos-test-obj-y += tests/libqos/virtio-mmio.o
 qos-test-obj-y += tests/libqos/virtio-net.o
 qos-test-obj-y += tests/libqos/virtio-pci.o
+qos-test-obj-y += tests/libqos/virtio-pci-modern.o
 qos-test-obj-y += tests/libqos/virtio-rng.o
 qos-test-obj-y += tests/libqos/virtio-scsi.o
 qos-test-obj-y += tests/libqos/virtio-serial.o
diff --git a/tests/libqos/virtio-pci-modern.h b/tests/libqos/virtio-pci-modern.h
new file mode 100644
index 0000000000..6bf2b207c3
--- /dev/null
+++ b/tests/libqos/virtio-pci-modern.h
@@ -0,0 +1,17 @@ 
+/*
+ * libqos virtio PCI VIRTIO 1.0 definitions
+ *
+ * Copyright (c) 2019 Red Hat, Inc
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef LIBQOS_VIRTIO_PCI_MODERN_H
+#define LIBQOS_VIRTIO_PCI_MODERN_H
+
+#include "virtio-pci.h"
+
+bool qvirtio_pci_init_virtio_1(QVirtioPCIDevice *dev);
+
+#endif /* LIBQOS_VIRTIO_PCI_MODERN_H */
diff --git a/tests/libqos/virtio-pci.h b/tests/libqos/virtio-pci.h
index 6b3a385b06..294d5567ee 100644
--- a/tests/libqos/virtio-pci.h
+++ b/tests/libqos/virtio-pci.h
@@ -27,6 +27,13 @@  typedef struct QVirtioPCIDevice {
     uint32_t config_msix_data;
 
     int bar_idx;
+
+    /* VIRTIO 1.0 */
+    uint32_t common_cfg_offset;
+    uint32_t notify_cfg_offset;
+    uint32_t notify_off_multiplier;
+    uint32_t isr_cfg_offset;
+    uint32_t device_cfg_offset;
 } QVirtioPCIDevice;
 
 struct QVirtioPCIMSIXOps {
@@ -43,6 +50,9 @@  typedef struct QVirtQueuePCI {
     uint16_t msix_entry;
     uint64_t msix_addr;
     uint32_t msix_data;
+
+    /* VIRTIO 1.0 */
+    uint64_t notify_offset;
 } QVirtQueuePCI;
 
 void virtio_pci_init(QVirtioPCIDevice *dev, QPCIBus *bus, QPCIAddress * addr);
diff --git a/tests/libqos/virtio-pci-modern.c b/tests/libqos/virtio-pci-modern.c
new file mode 100644
index 0000000000..18d118866f
--- /dev/null
+++ b/tests/libqos/virtio-pci-modern.c
@@ -0,0 +1,443 @@ 
+/*
+ * libqos VIRTIO 1.0 PCI driver
+ *
+ * Copyright (c) 2019 Red Hat, Inc
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "standard-headers/linux/pci_regs.h"
+#include "standard-headers/linux/virtio_pci.h"
+#include "standard-headers/linux/virtio_config.h"
+#include "virtio-pci-modern.h"
+
+static uint8_t config_readb(QVirtioDevice *d, uint64_t addr)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    return qpci_io_readb(dev->pdev, dev->bar, dev->device_cfg_offset + addr);
+}
+
+static uint16_t config_readw(QVirtioDevice *d, uint64_t addr)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    return qpci_io_readw(dev->pdev, dev->bar, dev->device_cfg_offset + addr);
+}
+
+static uint32_t config_readl(QVirtioDevice *d, uint64_t addr)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    return qpci_io_readl(dev->pdev, dev->bar, dev->device_cfg_offset + addr);
+}
+
+static uint64_t config_readq(QVirtioDevice *d, uint64_t addr)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    return qpci_io_readq(dev->pdev, dev->bar, dev->device_cfg_offset + addr);
+}
+
+static uint64_t get_features(QVirtioDevice *d)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    uint64_t lo, hi;
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            device_feature_select),
+                   0);
+    lo = qpci_io_readl(dev->pdev, dev->bar, dev->common_cfg_offset +
+                       offsetof(struct virtio_pci_common_cfg, device_feature));
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            device_feature_select),
+                   1);
+    hi = qpci_io_readl(dev->pdev, dev->bar, dev->common_cfg_offset +
+                       offsetof(struct virtio_pci_common_cfg, device_feature));
+
+    return (hi << 32) | lo;
+}
+
+static void set_features(QVirtioDevice *d, uint64_t features)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    /* Drivers must enable VIRTIO 1.0 or else use the Legacy interface */
+    g_assert_cmphex(features & (1ull << VIRTIO_F_VERSION_1), !=, 0);
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            guest_feature_select),
+                   0);
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            guest_feature),
+                   features);
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            guest_feature_select),
+                   1);
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            guest_feature),
+                   features >> 32);
+}
+
+static uint64_t get_guest_features(QVirtioDevice *d)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    uint64_t lo, hi;
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            guest_feature_select),
+                   0);
+    lo = qpci_io_readl(dev->pdev, dev->bar, dev->common_cfg_offset +
+                       offsetof(struct virtio_pci_common_cfg, guest_feature));
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg,
+                            guest_feature_select),
+                   1);
+    hi = qpci_io_readl(dev->pdev, dev->bar, dev->common_cfg_offset +
+                       offsetof(struct virtio_pci_common_cfg, guest_feature));
+
+    return (hi << 32) | lo;
+}
+
+static uint8_t get_status(QVirtioDevice *d)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    return qpci_io_readb(dev->pdev, dev->bar, dev->common_cfg_offset +
+                         offsetof(struct virtio_pci_common_cfg,
+                                  device_status));
+}
+
+static void set_status(QVirtioDevice *d, uint8_t status)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    return qpci_io_writeb(dev->pdev, dev->bar, dev->common_cfg_offset +
+                          offsetof(struct virtio_pci_common_cfg,
+                                   device_status),
+                          status);
+}
+
+static bool get_msix_status(QVirtioPCIDevice *dev, uint32_t msix_entry,
+                            uint32_t msix_addr, uint32_t msix_data)
+{
+    uint32_t data;
+
+    g_assert_cmpint(msix_entry, !=, -1);
+    if (qpci_msix_masked(dev->pdev, msix_entry)) {
+        /* No ISR checking should be done if masked, but read anyway */
+        return qpci_msix_pending(dev->pdev, msix_entry);
+    }
+
+    data = qtest_readl(dev->pdev->bus->qts, msix_addr);
+    if (data == msix_data) {
+        qtest_writel(dev->pdev->bus->qts, msix_addr, 0);
+        return true;
+    } else {
+        return false;
+    }
+}
+
+static bool get_queue_isr_status(QVirtioDevice *d, QVirtQueue *vq)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    if (dev->pdev->msix_enabled) {
+        QVirtQueuePCI *vqpci = container_of(vq, QVirtQueuePCI, vq);
+
+        return get_msix_status(dev, vqpci->msix_entry, vqpci->msix_addr,
+                               vqpci->msix_data);
+    }
+
+    return qpci_io_readb(dev->pdev, dev->bar, dev->isr_cfg_offset) & 1;
+}
+
+static bool get_config_isr_status(QVirtioDevice *d)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    if (dev->pdev->msix_enabled) {
+        return get_msix_status(dev, dev->config_msix_entry,
+                               dev->config_msix_addr, dev->config_msix_data);
+    }
+
+    return qpci_io_readb(dev->pdev, dev->bar, dev->isr_cfg_offset) & 2;
+}
+
+static void wait_config_isr_status(QVirtioDevice *d, gint64 timeout_us)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    gint64 start_time = g_get_monotonic_time();
+
+    do {
+        g_assert(g_get_monotonic_time() - start_time <= timeout_us);
+        qtest_clock_step(dev->pdev->bus->qts, 100);
+    } while (!get_config_isr_status(d));
+}
+
+static void queue_select(QVirtioDevice *d, uint16_t index)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    qpci_io_writew(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_select),
+                   index);
+}
+
+static uint16_t get_queue_size(QVirtioDevice *d)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    return qpci_io_readw(dev->pdev, dev->bar, dev->common_cfg_offset +
+                         offsetof(struct virtio_pci_common_cfg, queue_size));
+}
+
+static void set_queue_address(QVirtioDevice *d, QVirtQueue *vq)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_desc_lo),
+                   vq->desc);
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_desc_hi),
+                   vq->desc >> 32);
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_avail_lo),
+                   vq->avail);
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_avail_hi),
+                   vq->avail >> 32);
+
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_used_lo),
+                   vq->used);
+    qpci_io_writel(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_used_hi),
+                   vq->used >> 32);
+}
+
+static QVirtQueue *virtqueue_setup(QVirtioDevice *d, QGuestAllocator *alloc,
+                                   uint16_t index)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    QVirtQueue *vq;
+    QVirtQueuePCI *vqpci;
+    uint16_t notify_off;
+
+    vq = qvirtio_pci_virtqueue_setup_common(d, alloc, index);
+    vqpci = container_of(vq, QVirtQueuePCI, vq);
+
+    notify_off = qpci_io_readw(dev->pdev, dev->bar, dev->common_cfg_offset +
+                               offsetof(struct virtio_pci_common_cfg,
+                                        queue_notify_off));
+
+    vqpci->notify_offset = dev->notify_cfg_offset +
+                           notify_off * dev->notify_off_multiplier;
+
+    qpci_io_writew(dev->pdev, dev->bar, dev->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_enable), 1);
+
+    return vq;
+}
+
+static void virtqueue_kick(QVirtioDevice *d, QVirtQueue *vq)
+{
+    QVirtioPCIDevice *dev = container_of(d, QVirtioPCIDevice, vdev);
+    QVirtQueuePCI *vqpci = container_of(vq, QVirtQueuePCI, vq);
+
+    qpci_io_writew(dev->pdev, dev->bar, vqpci->notify_offset, vq->index);
+}
+
+static const QVirtioBus qvirtio_pci_virtio_1 = {
+    .config_readb = config_readb,
+    .config_readw = config_readw,
+    .config_readl = config_readl,
+    .config_readq = config_readq,
+    .get_features = get_features,
+    .set_features = set_features,
+    .get_guest_features = get_guest_features,
+    .get_status = get_status,
+    .set_status = set_status,
+    .get_queue_isr_status = get_queue_isr_status,
+    .wait_config_isr_status = wait_config_isr_status,
+    .queue_select = queue_select,
+    .get_queue_size = get_queue_size,
+    .set_queue_address = set_queue_address,
+    .virtqueue_setup = virtqueue_setup,
+    .virtqueue_cleanup = qvirtio_pci_virtqueue_cleanup_common,
+    .virtqueue_kick = virtqueue_kick,
+};
+
+static void set_config_vector(QVirtioPCIDevice *d, uint16_t entry)
+{
+    uint16_t vector;
+
+    qpci_io_writew(d->pdev, d->bar, d->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, msix_config), entry);
+    vector = qpci_io_readw(d->pdev, d->bar, d->common_cfg_offset +
+                           offsetof(struct virtio_pci_common_cfg,
+                                    msix_config));
+    g_assert_cmphex(vector, !=, VIRTIO_MSI_NO_VECTOR);
+}
+
+static void set_queue_vector(QVirtioPCIDevice *d, uint16_t vq_idx,
+                             uint16_t entry)
+{
+    uint16_t vector;
+
+    queue_select(&d->vdev, vq_idx);
+    qpci_io_writew(d->pdev, d->bar, d->common_cfg_offset +
+                   offsetof(struct virtio_pci_common_cfg, queue_msix_vector),
+                   entry);
+    vector = qpci_io_readw(d->pdev, d->bar, d->common_cfg_offset +
+                           offsetof(struct virtio_pci_common_cfg,
+                                    queue_msix_vector));
+    g_assert_cmphex(vector, !=, VIRTIO_MSI_NO_VECTOR);
+}
+
+static const QVirtioPCIMSIXOps qvirtio_pci_msix_ops_virtio_1 = {
+    .set_config_vector = set_config_vector,
+    .set_queue_vector = set_queue_vector,
+};
+
+static bool probe_device_type(QVirtioPCIDevice *dev)
+{
+    uint16_t vendor_id;
+    uint16_t device_id;
+
+    /* "Drivers MUST match devices with the PCI Vendor ID 0x1AF4" */
+    vendor_id = qpci_config_readw(dev->pdev, PCI_VENDOR_ID);
+    if (vendor_id != 0x1af4) {
+        return false;
+    }
+
+    /*
+     * "Any PCI device with ... PCI Device ID 0x1000 through 0x107F inclusive
+     * is a virtio device"
+     */
+    device_id = qpci_config_readw(dev->pdev, PCI_DEVICE_ID);
+    if (device_id < 0x1000 || device_id > 0x107f) {
+        return false;
+    }
+
+    /*
+     * "Devices MAY utilize a Transitional PCI Device ID range, 0x1000 to
+     * 0x103F depending on the device type"
+     */
+    if (device_id < 0x1040) {
+        /*
+         * "Transitional devices MUST have the PCI Subsystem Device ID matching
+         * the Virtio Device ID"
+         */
+        dev->vdev.device_type = qpci_config_readw(dev->pdev, PCI_SUBSYSTEM_ID);
+    } else {
+        /*
+         * "The PCI Device ID is calculated by adding 0x1040 to the Virtio
+         * Device ID"
+         */
+        dev->vdev.device_type = device_id - 0x1040;
+    }
+
+    return true;
+}
+
+/* Find the first VIRTIO 1.0 PCI structure for a given type */
+static bool find_structure(QVirtioPCIDevice *dev, uint8_t cfg_type,
+                           uint8_t *bar, uint32_t *offset, uint32_t *length,
+                           uint8_t *cfg_addr)
+{
+    uint8_t addr = 0;
+
+    while ((addr = qpci_find_capability(dev->pdev, PCI_CAP_ID_VNDR,
+                                        addr)) != 0) {
+        uint8_t type;
+
+        type = qpci_config_readb(dev->pdev,
+                addr + offsetof(struct virtio_pci_cap, cfg_type));
+        if (type != cfg_type) {
+            continue;
+        }
+
+        *bar = qpci_config_readb(dev->pdev,
+                addr + offsetof(struct virtio_pci_cap, bar));
+        *offset = qpci_config_readl(dev->pdev,
+                addr + offsetof(struct virtio_pci_cap, offset));
+        *length = qpci_config_readl(dev->pdev,
+                addr + offsetof(struct virtio_pci_cap, length));
+        if (cfg_addr) {
+            *cfg_addr = addr;
+        }
+
+        return true;
+    }
+
+    return false;
+}
+
+static bool probe_device_layout(QVirtioPCIDevice *dev)
+{
+    uint8_t bar;
+    uint8_t cfg_addr;
+    uint32_t length;
+
+    /*
+     * Due to the qpci_iomap() API we only support devices that put all
+     * structures in the same PCI BAR.  Luckily this is true with QEMU.
+     */
+
+    if (!find_structure(dev, VIRTIO_PCI_CAP_COMMON_CFG, &bar,
+                        &dev->common_cfg_offset, &length, NULL)) {
+        return false;
+    }
+    dev->bar_idx = bar;
+
+    if (!find_structure(dev, VIRTIO_PCI_CAP_NOTIFY_CFG, &bar,
+                        &dev->notify_cfg_offset, &length, &cfg_addr)) {
+        return false;
+    }
+    g_assert_cmphex(bar, ==, dev->bar_idx);
+
+    dev->notify_off_multiplier = qpci_config_readl(dev->pdev,
+            cfg_addr + offsetof(struct virtio_pci_notify_cap,
+                                notify_off_multiplier));
+
+    if (!find_structure(dev, VIRTIO_PCI_CAP_ISR_CFG, &bar,
+                        &dev->isr_cfg_offset, &length, NULL)) {
+        return false;
+    }
+    g_assert_cmphex(bar, ==, dev->bar_idx);
+
+    if (!find_structure(dev, VIRTIO_PCI_CAP_DEVICE_CFG, &bar,
+                        &dev->device_cfg_offset, &length, NULL)) {
+        return false;
+    }
+    g_assert_cmphex(bar, ==, dev->bar_idx);
+
+    return true;
+}
+
+/* Probe a VIRTIO 1.0 device */
+bool qvirtio_pci_init_virtio_1(QVirtioPCIDevice *dev)
+{
+    if (!probe_device_type(dev)) {
+        return false;
+    }
+
+    if (!probe_device_layout(dev)) {
+        return false;
+    }
+
+    dev->vdev.bus = &qvirtio_pci_virtio_1;
+    dev->msix_ops = &qvirtio_pci_msix_ops_virtio_1;
+    dev->vdev.big_endian = false;
+    return true;
+}
diff --git a/tests/libqos/virtio-pci.c b/tests/libqos/virtio-pci.c
index 11866f7772..62851c29bb 100644
--- a/tests/libqos/virtio-pci.c
+++ b/tests/libqos/virtio-pci.c
@@ -22,6 +22,8 @@ 
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_regs.h"
 
+#include "virtio-pci-modern.h"
+
 /* virtio-pci is a superclass of all virtio-xxx-pci devices;
  * the relation between virtio-pci and virtio-xxx-pci is implicit,
  * and therefore virtio-pci does not produce virtio and is not
@@ -401,7 +403,9 @@  static void qvirtio_pci_init_from_pcidev(QVirtioPCIDevice *dev, QPCIDevice *pci_
     dev->pdev = pci_dev;
     dev->config_msix_entry = -1;
 
-    qvirtio_pci_init_legacy(dev);
+    if (!qvirtio_pci_init_virtio_1(dev)) {
+        qvirtio_pci_init_legacy(dev);
+    }
 
     /* each virtio-xxx-pci device should override at least this function */
     dev->obj.get_driver = NULL;