<html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> </head> <body text="#000000" bgcolor="#FFFFFF"> 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 <a moz-do-not-send="true" href="http://vfio.blogspot.com/2014/08/does-my-graphics-card-rom-support-efi.html">attempting to go through the steps myself</a> (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 : <pre>cat: '/sys/bus/pci/devices/0000:07:00.0/rom': Input/output error </pre> Accompanied by the following like in dmesg : <pre>[ 1734.316429] vfio-pci 0000:07:00.0: Invalid PCI ROM header signature: expecting 0xaa55, got 0xffff </pre> This isn't a recent thing, <a moz-do-not-send="true" href="https://www.reddit.com/r/VFIO/comments/971umf/is_everyone_else_getting_invalid_pci_rom_header/">I started investigating this several months ago</a> 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 <a moz-do-not-send="true" href="https://unix.stackexchange.com/a/474378">resetting the PCI port the device is attached to</a>, 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 </body> </html>