On 20.10.20 22:44, Peter Xu wrote:
> On Tue, Oct 20, 2020 at 10:01:12PM +0200, David Hildenbrand wrote:
>> Thanks ... but I have an AMD system. Will try to find out how to get
>> that running with AMD :)
>
> May still start with trying intel-iommu first. :) I think it should work for
> amd hosts too.
>
> Just another FYI - Wei is working on amd-iommu for vfio [1], but it's still
> during review.
>
> [1]
> https://lore.kernel.org/qemu-devel/20201002145907.1294353-1-wei.hua...@amd.com/
>
I'm trying to get an iommu setup running (without virtio-mem!),
but it's a big mess.
Essential parts of my QEMU cmdline are:
sudo build/qemu-system-x86_64 \
-accel kvm,kernel-irqchip=split \
...
device pcie-pci-bridge,addr=1e.0,id=pci.1 \
-device vfio-pci,host=0c:00.0,x-vga=on,bus=pci.1,addr=1.0,multifunction=on \
-device vfio-pci,host=0c:00.1,bus=pci.1,addr=1.1 \
-device intel-iommu,caching-mode=on,intremap=on \
I am running upstream QEMU + Linux -next kernel inside the
guest on an AMD Ryzen 9 3900X 12-Core Processor.
I am using SeaBios.
I tried faking an Intel CPU without luck.
("-cpu Skylake-Client,kvm=off,vendor=GenuineIntel")
As soon as I enable "intel_iommu=on" in my guest kernel, graphics
stop working (random mess on graphics output) and I get
vfio-pci 0000:0c:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0023
address=0xff924000 flags=0x0000]
in the hypervisor, along with other nice messages.
I can spot no vfio DMA mappings coming from an iommu, just as if the
guest wouldn't even try to setup the iommu.
I tried with
1. AMD Radeon RX Vega 56
2. Nvidia GT220
resulting in similar issues.
I also tried with "-device amd-iommu" with other issues
(guest won't even boot up). Are my graphics card missing some support or
is there a fundamental flaw in my setup?
Any clues appreciated.
--
Thanks,
David / dhildenb
