Hi Nicolas, Alex, On 3/11/19 9:39 AM, Auger Eric wrote: > Hi Nicolas, > > On 3/10/19 11:06 PM, Nicolas Roy-Renaud 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 > > Last time I got this error was when a readw was attempted in > pci_map_rom/pci_get_rom_size while the Device Control memory space > access bit was disabled in PCI cfg space. At the time you attempt to > dump the rom, the guest may have disabled this bit?
Sorry I missed your intermediate replies. So it looks the same issue. Thanks Eric > > Thanks > > Eric >> >> This isn't a recent thing, I started investigating this several months >> ago >> <https://www.reddit.com/r/VFIO/comments/971umf/is_everyone_else_getting_invalid_pci_rom_header/> >> and it turned out that I wasn't alone: Everyone on the VFIO discord chat >> who actually tried this got the same error message. >> >> The interesting part is that launching and shutting down a VM using that >> device clears the issue and it then becomes possible to dump the ROM as >> expected. I've known a number of issues with VFIO and ROMs can be >> resolved either like this or by attaching the guest GPU on an already >> live VM (for reasons I admittedly don't quite understand myself), but >> since getting a ROM dump can be an important part of setting up the VM >> that will receive the device in the first place, I don't know if this >> could be considered an option. >> >> I figured this had something to do with the host BIOS tainting the ROM >> on boot, which is a well known thing on boot GPUs (even though the one >> I'm attempting to dump isn't), and that passing the tainted GPU to a VM >> then causes the device to power cycle and clears that, somehow? With >> that in mind, I've attempted a number of things, but neither resetting >> the PCI port the device is attached to >> <https://unix.stackexchange.com/a/474378>, nor doing function-reset on >> the device, nor going in and out of sleep mode on the guest seems to >> resolve the issue. I've also tried using pci-stub instead of vfio-pci to >> see if this wasn't a driver issue, but no success here either. >> >> Is there anyone with better technical knowledge of VFIO who could help >> with this? >> >> - Nicolas >> >> >> _______________________________________________ >> vfio-users mailing list >> vfio-users@redhat.com >> https://www.redhat.com/mailman/listinfo/vfio-users >> > > _______________________________________________ > vfio-users mailing list > vfio-users@redhat.com > https://www.redhat.com/mailman/listinfo/vfio-users > _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users
