[vfio-users] Windows 10 guest refuses to boot when passed my NVIDIA graphics card

[Jasen Borisov]

On Tue, Sep 15, 2015 at 10:34 PM, Alex Williamson <
alex.l.williamson at gmail.com> wrote:

> On Tue, Sep 15, 2015 at 9:32 AM, Jasen Borisov <tajjada at gmail.com> wrote:
>
>> Hello everyone,
>>
>> I have been following the guides on the vfio blogspot for setting up a
>> Windows guest for gaming by passing it my NVIDIA GeForce GTX 980 graphics
>> card. I have an AMD Radeon R7 250 graphics card for my Linux host. I have
>> ran into a strange problem and have not managed to find a solution to it
>> online, so I decided to come here and see if anyone knows anything about it.
>>
>> Here is the problem I am facing:
>>
>> I installed the Windows guest (Windows 10 Pro) in a kvm virtual machine
>> made with virt-manager, using the default qxl/spice setup during the
>> installation, as instructed here
>> <http://vfio.blogspot.bg/2015/05/vfio-gpu-how-to-series-part-4-our-first.html>.
>> After the installation completed, I removed any extra virtual devices and
>> added the PCI host/vfio device for my NVIDIA graphics card. I also edited
>> the XML to hide the kvm virtualization, in preparation for installing the
>> NVIDIA drivers on Windows, when I boot with my actual graphics card. I have
>> made no attempt to configure hugepages yet.
>>
>> However, when starting up the VM, Windows no longer booted successfully.
>> I saw the Tianocore splash on my physical monitor, followed by the Windows
>> logo. The Windows logo stayed frozen (without the spinning loading
>> indicator under it) for a few minutes, and then the spinning-dots loading
>> indicator appeared for a few seconds and the machine *reset*. It kept
>> resetting again and again, never getting past the Windows boot screen.
>>
>> I would assume that my PCI passthrough worked successfully, since my
>> physical monitor turned on and I saw the video output from the virtual
>> machine on it. However, I can't figure out why Windows cannot finish
>> booting successfully. Any help with this issue would be greatly appreciated.
>>
>> The same copy of Windows (or rather, installed from the same installation
>> ISO) works fine with my NVIDIA card on my actual hardware / when not in a
>> virtual machine, so I am sure this is not a hardware problem.
>>
>>
>> Here is some relevant information about my system:
>>
>> /proc/cmdline:
>> ... intel_iommu=on iommu=pt vfio-pci.ids=10de:13c0,10de:0fbb,8086:8d26
>> vfio.disable_vga=1 ...
>>
>
> disable_vga is a vfio-pci option, vfio-pci.disable_vga=1
>

Ok, thanks, will change that. Not sure if it matters though, since both the
host and guest are booting with UEFI.


>
>
(I omitted my rootfs and other irrelevant kernel options)
>> The PCI IDs listed in my kernel commandline are my GPU, its audio, and an
>> EHCI controller on my system for USB, in that order.
>>
>> I did not need to use any "hacks" like the ACS override patch or the
>> enable_unsafe_interrupts option, since I did not experience the relevant
>> issues that they were made to fix. Each one of the PCI IDs above is in its
>> own IOMMU group.
>>
>
> Are you sure about that?  The GPU and audio always share a group as far as
> I've seen.
>
>

Ah yes, that is true, the gpu and audio are the same group, but I am
passing them both to the VM, so I don't need to split them, hence no need
for ACS. What I meant is that my gpu/audio is a separate group from
everything else, and so is the EHCI controller I wanted to pass.


> My system has no integrated graphics (Core i7 Extreme 5960X CPU).
>>
>
> The XML indicates you're running at least QEMU 2.4, but what kernel
> version are you using?  I'll guess at least v4.1 based on vfio commandline
> options, but it'd be nice to know.
>
>

Kernel 4.2.0, custom build/config.


> These lines appeared in dmesg when the VM started:
>>
>> [  582.886435] kvm: SMP vm created on host with unstable TSC; guest TSC
>> will not be reliable
>>
>
> I'd be a little concerned by this if I were you.
>
> Why? What problems could it lead to / why is it concerning? Is there
anything I can do about it? I googled that message when I first saw it, and
I was left with the impression that it is a hardware issue that I can do
nothing about, so I just have to deal with it and hope everything will
work. I thought the worst thing it can cause is jitter/stuttering in the
VM. Perhaps I am wrong?


> Are you using "options kvm ignore_msrs=1" in modprobe.d?
>

No, I am not. Should I be using that?

(also, kvm is builtin on my kernel, so, if yes, will have to add that to
kernel commandline instead of modprobe.d)
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