Re: [Qemu-devel] VFIO-VGA Issue

[Alex Williamson]

On Tue, 2013-04-09 at 18:33 -0400, address@hidden wrote:
> Here's debug output from qemu, the last lines repeat indefinitely:
> 
> vfio: vfio_initfn(0000:01:00.0) group 1
> vfio: region_add 0 - 7fffffff [0x7f605fe00000]
> vfio: SKIPPING region_add fec00000 - fec00fff
> vfio: SKIPPING region_add fed00000 - fed003ff
> vfio: SKIPPING region_add fee00000 - feefffff
> vfio: SKIPPING region_add fffe0000 - ffffffff
> vfio: Device 0000:01:00.0 flags: 3, regions: 9, irgs: 3
> vfio: Device 0000:01:00.0 region 0:
> vfio:   size: 0x10000000, offset: 0x0, flags: 0x7
> vfio: Device 0000:01:00.0 region 1:
> vfio:   size: 0x0, offset: 0x10000000000, flags: 0x0
> vfio: Device 0000:01:00.0 region 2:
> vfio:   size: 0x40000, offset: 0x20000000000, flags: 0x7
> vfio: Device 0000:01:00.0 region 3:
> vfio:   size: 0x0, offset: 0x30000000000, flags: 0x0
> vfio: Device 0000:01:00.0 region 4:
> vfio:   size: 0x100, offset: 0x40000000000, flags: 0x3
> vfio: Device 0000:01:00.0 region 5:
> vfio:   size: 0x0, offset: 0x50000000000, flags: 0x0
> vfio: Device 0000:01:00.0 ROM:
> vfio:   size: 0x20000, offset: 0x60000000000, flags: 0x1
> vfio: Device 0000:01:00.0 config:
> vfio:   size: 0x1000, offset: 0x70000000000, flags: 0x3
> vfio: vfio_load_rom(0000:01:00.0)
> vfio: vfio_bar_write(0000:01:00.0:BAR4+0x0, 0x4010, 4)
> vfio: vfio_bar_read(0000:01:00.0:BAR4+0x4, 4) = 0xe000000c
> vfio: Enabled ATI/AMD quirk 0x4010 for device 0000:01:00.0
> vfio: Enabled ATI/AMD quirk 0x3c3 for device 0000:01:00.0
...
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0
> vfio: vfio_vga_read(0x3c3, 1) = 0x0

This is a quirk that I haven't fully figured out yet.  ATI/AMD cards use
VGA register 0x3c3 to read upper byte of the address of the I/O port
BAR, but sometimes it reads 0.  Try the patch below to have it always
return the virtual BAR address and let me know if it works.  Thanks,

Alex

--- a/hw/vfio_pci.c
+++ b/hw/vfio_pci.c
@@ -1117,7 +1117,7 @@ static uint64_t vfio_ati_3c3_quirk_read(void *opaque,
     uint64_t data = vfio_vga_read(&vdev->vga.region[QEMU_PCI_VGA_IO_HI],
                                   addr + 0x3, size);
 
-    if (data == quirk->data) {
+    if (1 || data == quirk->data) {
         data = pci_get_byte(pdev->config + PCI_BASE_ADDRESS_4 + 1);
         DPRINTF("%s(0x3c3, 1) = 0x%"PRIx64"\n", __func__, data);
     }