On Wed, Mar 16, 2016 at 6:42 AM, Bryan Jacobs <[email protected]> wrote:
> Hello VFIO users! > > Yesterday I was able to boot a Windows VM successfully with OVMF and a > passed-through graphics card. > > I'm not sure what changed, but today I get a libvirt qemu log full of > these messages: > > "qemu-system-x86_64: vfio_region_write(0000:01:00.0:region1+0x240c14, > 0xffffffff,4) failed: Device or resource busy" > > There are hundreds upon hundreds of these - it looks like it's walking a > large memory space, doing reads and writes, and failing every time. The > graphics card gives code 43, but the problem doesn't go away even if I > entirely disable enlightenments. Removing the PCIe passthrough devices gets > rid of the log entries. > > My two passed PCI devices are a GTX 980TI GPU and its HDMI audio function. > They are in their own IOMMU group with their own pci bridge. The CPU is an > i5-6600k. > > I have verified that the devices are bound to the vfio-pci driver, > although I don't seem to be able to entirely stop console output from > appearing on the graphics card on boot (not even with my CSM-free UEFI set > to use the integrated graphics instead). There's definitely nothing like X > running, and the nvidia module is unloaded in the host OS. > > # virsh --version > 1.3.2 > # uname -a > Linux host 4.4.5-1-ARCH #1 SMP PREEMPT Thu Mar 10 07:38:19 CET 2016 x86_64 > GNU/Linux > > Removing the passed-through device fixes the issue. > > What would make the vfio_region_(read|write) calls return EBUSY? I figured > I'd ask here before diving into the kernel sources :-/. > This is likely due to another driver in the host claiming some of the resources of the device. Check /proc/iomem to see if there are other drivers making use of some device regions.
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