Hey, Alex, thanks for replying.
It seems like you're right on the Mem- part.
[user@OCCAM ~]$ lspci -s 07:00.0 -vvv
07:00.0 VGA compatible controller: NVIDIA Corporation GM204 [GeForce GTX 970]
(rev a1) (prog-if 00 [VGA controller])
Subsystem: ASUSTeK Computer Inc. GM204 [GeForce GTX 970]
Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
For comparison, here's the result from last boot after firing up and
shutting down a VM using that device:
[user@OCCAM ~]$ lspci -s 07:00.0 -vvv
07:00.0 VGA compatible controller: NVIDIA Corporation GM204 [GeForce GTX 970]
(rev a1) (prog-if 00 [VGA controller])
Subsystem: ASUSTeK Computer Inc. GM204 [GeForce GTX 970]
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Yet when I try enabling the device, I get this :
[root@OCCAM user]# echo 1 > /sys/bus/pci/devices/0000:07:00.0/enable
bash: echo: write error: Device or resource busy
Other people have apparently had similar issues caused by other drivers
claiming the ressources, and /proc/iomem was showing efifb bound to that
device earlier, however neither disabling it in the kernel command line
or unbinding it once the system is live have solved the issue (even
though it no longer shows up in iomem). Here's PCI section from iomem
with video=efifb:off. All the commands whose outputs you'll see here
have been run under these conditions:
00000000-00000000 : PCI Bus 0000:00
00000000-00000000 : PCI Bus 0000:07
00000000-00000000 : 0000:07:00.0
00000000-00000000 : 0000:07:00.0
00000000-00000000 : PCI Bus 0000:01
00000000-00000000 : 0000:01:00.0
00000000-00000000 : 0000:01:00.0
00000000-00000000 : PCI Bus 0000:07
00000000-00000000 : 0000:07:00.0
00000000-00000000 : 0000:07:00.0
00000000-00000000 : 0000:07:00.1
00000000-00000000 : PCI Bus 0000:01
00000000-00000000 : 0000:01:00.0
00000000-00000000 : nvidia
00000000-00000000 : 0000:01:00.1
00000000-00000000 : ICH HD audio
00000000-00000000 : PCI Bus 0000:04
00000000-00000000 : 0000:04:00.0
00000000-00000000 : 0000:04:00.0
00000000-00000000 : ahci
00000000-00000000 : PCI Bus 0000:03
00000000-00000000 : 0000:03:00.0
00000000-00000000 : 0000:03:00.0
00000000-00000000 : r8169
00000000-00000000 : 0000:00:14.0
00000000-00000000 : xhci-hcd
00000000-00000000 : 0000:00:1b.0
00000000-00000000 : ICH HD audio
00000000-00000000 : 0000:00:1f.3
00000000-00000000 : 0000:00:1f.2
00000000-00000000 : ahci
00000000-00000000 : 0000:00:1d.0
00000000-00000000 : ehci_hcd
00000000-00000000 : 0000:00:1a.0
00000000-00000000 : ehci_hcd
00000000-00000000 : 0000:00:16.0
00000000-00000000 : mei_me
00000000-00000000 : PCI MMCONFIG 0000 [bus 00-3f]
00000000-00000000 : Reserved
00000000-00000000 : pnp 00:06
00000000-00000000 : Reserved
00000000-00000000 : IOAPIC 0
Enable reverts back to 0 after the VM using the device shuts down, and
trying to write 1 in that file still yields "Device or resource busy".
Also, unlike what I said earlier from the last time I looked into this,
it seems doing this no longer allows you to dump the ROM after the VM
has shut down, with the same error message as before.
- Nicolas
On 03/10/2019 10:09 PM, Alex Williamson wrote:
On Sun, 10 Mar 2019 18:06:37 -0400
Nicolas Roy-Renaud <nicolas.roy-renau...@ens.etsmtl.ca> wrote:
I've seen a lot of people before reccomand VFIO newcomers to flash their
GPU if they couldn't get their passthrough working right before, and
since I know how potentially risky and avoidable this sort of procedure
is (since QEMU lets you just pass your own ROM to the VM to be used
instead), and while attempting to go through the steps myself
<http://vfio.blogspot.com/2014/08/does-my-graphics-card-rom-support-efi.html>
(even though I've had a working VFIO setup for years), got something
unexpected.
Attempting to dump the ROM from my guest card _/freshly /_/_after a
reboot_/ results in the following error message :
cat: '/sys/bus/pci/devices/0000:07:00.0/rom': Input/output error
Accompanied by the following like in dmesg :
[ 1734.316429] vfio-pci 0000:07:00.0: Invalid PCI ROM header signature:
expecting 0xaa55, got 0xffff
If lspci for the device reports:
Control: I/O- Mem- BusMaster- ...
(specifically Mem-), this could be the reason it's failing. The PCI
ROM BAR is a memory region and memory decode needs to be enabled on the
device in order to get access to it. Also if you have the device
already bound to vfio-pci, the device might be in a D3 low power state,
which could make that memory region unavailable. You can use the
'enable' file in sysfs to fix both of these, so your sequence would
look like this:
echo 1 > /sys/bus/pci/devices/0000:07:00.0/enable
echo 1 > /sys/bus/pci/devices/0000:07:00.0/rom
cat /sys/bus/pci/devices/0000:07:00.0/rom > gpu.rom
echo 0 > /sys/bus/pci/devices/0000:07:00.0/rom
echo 0 > /sys/bus/pci/devices/0000:07:00.0/enable
Thanks,
Alex
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