Hey Alex, I'm seeing the firmware get a hold of the VBT (https://github.com/coreboot/coreboot/blob/master/src/drivers/intel/gma/opregion.c#L253) and write the location of the OpRegion to the ASLS PCI register (https://github.com/coreboot/coreboot/blob/master/src/drivers/intel/gma/opregion.c#L88). To sanity check, I booted and Chrome OS firmware put the OpRegion at 0x7aa9b520 (I can do `mem rm 0x7aa9b520 16` in the host and see it print out "IntelGraphicsMem"). So like you said, OpRegion is definitely there and used in the host.
This line (https://github.com/coreboot/coreboot/blob/master/src/drivers/intel/gma/opregion.c#L312) seems to imply that the VBT is being included in the OpRegion, so not sure whats going wrong. I am right in the middle of debugging this so I'll follow up on here if I have further specific questions. Thanks! On Tue, May 28, 2019 at 1:23 PM Alex Williamson <alex.william...@redhat.com> wrote: > > On Tue, 28 May 2019 09:35:16 -0700 > Micah Morton <mort...@chromium.org> wrote: > > > Ah ok thanks! > > > > The qemu command line i was using is here: `qemu-system-x86_64 > > -chardev stdio,id=seabios -device > > isa-debugcon,iobase=0x402,chardev=seabios -m 2G -smp 2 -M pc -vga none > > -usbdevice tablet -cpu host,-invpcid,-tsc-deadline,check -drive > > 'file=/path/to/image.bin,index=0,media=disk,cache=unsafe,format=raw' > > -enable-kvm -device > > vfio-pci,x-igd-opregion=on,host=00:02.0,id=hostdev0,bus=pci.0,addr=0x2,rombar=0 > > -device 'virtio-net,netdev=eth0' -netdev > > 'user,id=eth0,net=10.0.2.0/27,hostfwd=tcp:127.0.0.1:9222-:22'` > > > > It didn't work, but now at least I know why: > > [ 0.316117] i915 0000:00:02.0: No more image in the PCI ROM > > [ 0.316261] [drm] Failed to find VBIOS tables (VBT) > > > > If I can expose the VBT to the VM maybe it will work :) > > Hmm, looking at i915 it seems it didn't find this VBT thing in the > OpRegion so tried to look at the ROM, which comments indicate would > only be the VBT location on an older device. QEMU should fail if > x-igd-opregion=on is specified but the host kernel didn't provide an > OpRegion at all, so we've at least done some minimal sanity checking at > the host kernel before exposing it, but maybe the OpRegion is missing > some things on this chrome device vs a standard pc? Maybe Chrome OS > uses a modified i915 driver that doesn't depend on it so the firmware > guys stripped it? You could write a minimal vfio driver to dump > the opregion data if you want to parse it by hand. Thanks, > > Alex _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users
