[SeaBIOS] [PATCH 2/2] vp_init_simple: enable PCI bus-mastering before relying on DMA.

[Eric Northup]

An analogous change was made in the LSI scsi driver, commit
7d052575258ad2fc487ca3f9a6b62eff1b767900. Qemu works around guests that don't
correctly enable PCI bus mastering before using virtio queues' DMA (search for
VIRTIO_PCI_BUG_BUS_MASTER / VIRTIO_PCI_FLAG_BUS_MASTER_BUG ), but it'd be
better to be correct.

Signed-off-by: Eric Northup <digitaleric at google.com>
---
 src/hw/virtio-pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/hw/virtio-pci.c b/src/hw/virtio-pci.c
index a382504..b9b3ab1 100644
--- a/src/hw/virtio-pci.c
+++ b/src/hw/virtio-pci.c
@@ -90,6 +90,7 @@ u16 vp_init_simple(u16 bdf)
         PCI_BASE_ADDRESS_IO_MASK;
 
     vp_reset(ioaddr);
+    pci_config_maskw(bdf, PCI_COMMAND, 0, PCI_COMMAND_MASTER);
     vp_set_status(ioaddr, VIRTIO_CONFIG_S_ACKNOWLEDGE |
                   VIRTIO_CONFIG_S_DRIVER );
     return ioaddr;
-- 
1.9.0.279.gdc9e3eb