Re: [vfio-users] Getting nVIDIA SLI to work in a Windows 7 guest
On Mon, 17 May 2021 02:13:54 +0500
Roman Mamedov wrote:
> the nVIDIA driver presents no SLI option... because the GPUs are detected as
> connected either via PCI, or via "PCIe x0", and the driver also has a
> requirement for certain PCIe link width on both GPUs to unlock the SLI
> options
This appears to be the right guess. After presenting both GPUs as connected to
PCIe, the SLI options have appeared [1]. However the only way to get this
without the "Code 12" error was to use this weird topology:
...
-device pcie-root-port,id=gpu,bus=pcie.0,chassis=0,slot=0
-device
vfio-pci,host=08:00.0,multifunction=on,x-vga=on,bus=gpu,addr=0x00.0,romfile=vbios.rom
-device vfio-pci,host=09:00.0,bus=gpu,addr=0x00.1,romfile=vbios.rom
...
And after clicking Apply in that SLI control panel window, I just lose display
output ("No Signal"), and after a reboot both GPUs show the "Code 43" error
(unrelated to the usual passthrough detection).
I guess the driver didn't account for both GPUs being one multifunction device.
[1] https://romanrm.hk/2021-05-18T205357Z-sli1.png
--
With respect,
Roman
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[vfio-users] Getting nVIDIA SLI to work in a Windows 7 guest
Hello, I'm trying to get SLI of two GTX 970 to work in a Windows 7 VM. Some posts across the web such as [1] and [2] say that SLI as a concept is possible to get to work in a VM, but are light on technical details (such as the QEMU command line), and most likely use Windows 10, not 7. The issue I get is that when using the PCI topology for connecting GPUs, they both pass through fine, but the nVIDIA driver presents no SLI option, even though it's patched with DifferentSLIAuto. My guess is that is because the GPUs are detected as connected either via PCI, or via "PCIe x0", and the driver also has a requirement for certain PCIe link width on both GPUs to unlock the SLI options -- and DifferentSLIAuto does not disable that requirement. As such I believe I need to pass through the GPUs using PCIe topology, i.e. adding two pcie-root-port devices and connecting the GPUs to those. Problem is, when I do that, the second GPU gets a "Code 12" (not enough resources) error in the guest. I found a "hack" provided by Microsoft to resolve that error for devices on non-trivial PCIe topologies at [3], but it does not help. Does anyone have an idea of what else to try? Maybe someone has SLI working currently? Thanks [1] https://forums.unraid.net/topic/81750-working-2x-1080ti-sli-in-unraid/ [2] https://www.reddit.com/r/VFIO/comments/ay5o0j/success_rtx_2080ti_wsli_threadripper2_on/ [3] https://docs.microsoft.com/en-US/troubleshoot/windows-client/deployment/error-attach-pci-express-expansion-chassis -- With respect, Roman ___ vfio-users mailing list vfio-users@redhat.com https://listman.redhat.com/mailman/listinfo/vfio-users
