diff options
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/virtio/virtio-pci.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index ddb5da181c..a827cd41bf 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -314,6 +314,16 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val) msix_unuse_all_vectors(&proxy->pci_dev); } + /* Linux before 2.6.34 drives the device without enabling + the PCI device bus master bit. Enable it automatically + for the guest. This is a PCI spec violation but so is + initiating DMA with bus master bit clear. */ + if (val == (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)) { + pci_default_write_config(&proxy->pci_dev, PCI_COMMAND, + proxy->pci_dev.config[PCI_COMMAND] | + PCI_COMMAND_MASTER, 1); + } + /* Linux before 2.6.34 sets the device as OK without enabling the PCI device bus master bit. In this case we need to disable some safety checks. */ |