On Sat, 2012-10-06 at 18:23 -0700, Gordon Messmer wrote: > I started trying to pass through a PCI-E card to a KVM guest early this > year. Other hardware can be passed through successfully, but the guest > sees the wrong option ROM for this card. > > My system is an AMD CPU and GA-970A-D3 motherboard. There are currently > two Radeon HD 3470 cards installed, partially so that I could read their > ROMs into a file. > > The host OS is CentOS 6.3, and I've updated seabios and qemu to current > versions. > > My guest is started with: > > /usr/local/bin/qemu-system-x86_64 ... -vga cirrus \ > -device pci-assign,host=05:00.0,id=hostdev1,configfd=27,\ > bus=pci.0,addr=0x5,romfile=/var/lib/libvirt/images/Radeon3470-5.rom > > However, when the guest tries to read the ROM for the ATI card, it's > seeing the ROM for the emulated cirrus card instead: > > # strings /sys/devices/pci0000:00/0000:00:05.0/rom | head -4 > Plex86/Bochs VGABios (PCI) > current-cvs 23 Sep 2012 > (C) 2008 the LGPL VGABios developers Team > > If I don't pass an emulated VGA device (and modify seabios to not run > the VGA ROM), the guess won't read anything from the rom at all. > > Can anyone point me at which parts of the code I might review to see > where things are getting mapped and what's going wrong? The comments in linux:/drivers/pci/rom.c:pci_map_rom are probably relevant. Linux decides based on the VGA enable bit whether to return the PCI option ROM or legacy VGA ROM. In your case, it's giving you the legacy ROM from the cirrus device. The next step is probably looking at generating a PCI topology in the guest similar to a physical system when multiple VGA devices are present. That means bridges and/or root ports with VGA routing control. > > On the host system, lspci describes the device: > > 05:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI > RV620 PRO [Radeon HD 3470] (prog-if 00 [VGA controller]) > Subsystem: Dell Device 3243 > Flags: fast devsel, IRQ 26 > Memory at c0000000 (64-bit, prefetchable) [size=256M] > Memory at fd9f0000 (64-bit, non-prefetchable) [size=64K] > I/O ports at ae00 [size=256] > Expansion ROM at fd900000 [disabled] [size=128K] > and in the guest (Fedora 17): > > 00:05.0 VGA compatible controller: ATI Technologies Inc Mobility Radeon > HD 3470 (prog-if 00 [VGA controller]) > Subsystem: Dell Device 3243 > Physical Slot: 5 > Flags: fast devsel, IRQ 11 > Memory at e0000000 (32-bit, non-prefetchable) [size=256M] > Memory at f2030000 (32-bit, non-prefetchable) [size=64K] > I/O ports at c100 [size=256] > Expansion ROM at f2040000 [disabled] [size=64K] What's the size of Radeon3470-5.rom? When using romfile the size of the option ROM BAR is made to be big enough to contain the ROM. Without that, we match the physical device and expose the BAR as potentially being bigger than the ROM it contains. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
