[Qemu-devel] [PATCH] VirtIO: Fix QEMU crash during Windows PNP tests

[Yan Vugenfirer]

Signed-off-by: Yan Vugenfirer <address@hidden>

---
 hw/virtio-pci.c |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index f812ab7..a0a22c4 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -364,8 +364,17 @@ static void virtio_map(PCIDevice *pci_dev, int region_num,
 static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
                                 uint32_t val, int len)
 {
+    VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);
+
+    if (PCI_COMMAND == address) {
+        if (!(val & PCI_COMMAND_MASTER)) {
+            proxy->vdev->status &= ~VIRTIO_CONFIG_S_DRIVER_OK;
+        }
+    }
+
     pci_default_write_config(pci_dev, address, val, len);
-    msix_write_config(pci_dev, address, val, len);
+    if(proxy->vdev->nvectors)
+        msix_write_config(pci_dev, address, val, len);
 }
 
 static const VirtIOBindings virtio_pci_bindings = {
@@ -407,11 +416,12 @@ static void virtio_init_pci(VirtIOPCIProxy *proxy, 
VirtIODevice *vdev,
                          msix_bar_size(&proxy->pci_dev),
                          PCI_ADDRESS_SPACE_MEM,
                          msix_mmio_map);
-        proxy->pci_dev.config_write = virtio_write_config;
         proxy->pci_dev.unregister = msix_uninit;
     } else
         vdev->nvectors = 0;
 
+    proxy->pci_dev.config_write = virtio_write_config;
+
     size = VIRTIO_PCI_REGION_SIZE(&proxy->pci_dev) + vdev->config_len;
     if (size & (size-1))
         size = 1 << qemu_fls(size);
-- 
1.5.5.6