Prasad Joshi wrote:
On Wed, Feb 9, 2011 at 4:33 PM, Konstantin Khlebnikov
<[email protected] <mailto:[email protected]>> wrote:
Prasad Joshi wrote:
I was previously seeing a problem with the ROM BIOS, but I could
solve
it by passing a correct BIOS file in function assigned_initfn.
For now
I am using hardcoded file name in the code.
Did you recheck video bios inside guest? (for example in sysfs)
For GPU cards on my machine, reading from the
/sys/bus/pci/devices/<device>/rom always give error 'Invalid Argument'.
Yep, rom in sysfs must be enabled before via 'echo 1 > rom'
If rom was corrupted you will see warning in dmesg.
I had to extract the BIOS using some utilities. The BIOS seems to be
correct as I have been able to pass-through a old Nvidia (NVS 290) and
old ATI (RV370 FireGL V3100) card to Ubuntu Guest OS.
If this is bootstrap vga, guest linux kernel will use bios copy
placed at 0xc0000.
But in my setup qemu can only pass first 32k of option-roms,
due to curruption at seabios shadow-copying stage.
(seems like because improper i440fx PAM registers emulation)
I am not sure if it is related to the problem you are facing. The
current SeaBIOS has very limited pci memory space from 0xf0000000 to
0xfec00000 (236MB). This includes everything, prefectable and
non-prefecthable memory. The range is very small for VGA cards to work.
I have modified the memory range on my machine for prefectable memory.
But if in your guest /sys/bus/pci/devices/<device>/boot_vga == 1
linux will use shadow copy from 0xc0000 instead of pci rom bar
There is one bug in qemu-kvm code, which acidently detects the
prefectable memory as non-prefectable. I had sent a patch to correct
this behavior yesterday. Hope it gets accepted.
Yes, I saw him, IORESOURCE_PREFETCH was accidentally changed in linux kernel.
Maybe better to detect it via opening and mapping /resorce<id>_wc instad of
/resource<id>,
it exist only for prefechable resources. Plus qemu will get write-combined
mapping.
Thanks and Regards,
Prasad
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