[vfio-users] Cannot fix Error 43 for GTX 680 passed through to win 10 guest

Alex Williamson alex.williamson at redhat.com
Wed Oct 14 02:05:41 UTC 2015


On Tue, 2015-10-13 at 20:26 +0000, root at yoshi.dynu.com wrote:
> Sorry,
> 
> http://pastebin.com/Ng7jmDL1
> 
> same errors but other adresses...

Right, so the address follows the guest physical address space.  The
faults are to addresses that should be valid guest physical addresses in
the IOMMU.

I notice this in your dmesg:

        DMAR: Recommended TLB entries for ISOCH unit is 16; your BIOS set 20

I don't know that those 4 extra TLB entries are significant, but this
indicates that you have a specific audio device that happens to have a
couple quirks in the Intel VT-d code.  That also happens to be the same
audio device that you're trying to assign to the guest.

Your typical GTX680 VM setup assigns 00:1b.0 while your GT9600 VMs do
not.  Have you run tests with the GTX680 *without* the audio device
assigned?  If not, please do.

You might also want to try the 'strict' option of intel_iommu
(intel_iommu=on,strict), which will avoid lazy flushing in the IOMMU.
Thanks,

Alex




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