Re: [Bug Report] smmuv3 event 0x10 report when running virtio-blk-pci

[Eric Auger <eric.auger@redhat.com>]

Hi,

On 9/10/24 03:24, Zhou Wang via wrote:
> On 2024/9/9 22:31, Peter Maydell wrote:
>> On Mon, 9 Sept 2024 at 15:22, Zhou Wang via <qemu-devel@nongnu.org> wrote:
>>> Hi All,
>>>
>>> When I tested mainline qemu(commit 7b87a25f49), it reports smmuv3 event 0x10
>>> during kernel booting up.
>> Does it still do this if you either:
>>  (1) use the v9.1.0 release (commit fd1952d814da)
>>  (2) use "-machine virt-9.1" instead of "-machine virt"
> I tested above two cases, the problem is still there.

I have not much progressed yet but I see it comes with
qemu traces.

smmuv3-iommu-memory-region-0-0 translation failed for iova=0x0
(SMMU_EVT_F_TRANSLATION)
../..
qemu-system-aarch64: virtio-blk failed to set guest notifier (-22),
ensure -accel kvm is set.
qemu-system-aarch64: virtio_bus_start_ioeventfd: failed. Fallback to
userspace (slower).

the PCIe Host bridge seems to cause that translation failure at iova=0

Also virtio-iommu has the same issue:
qemu-system-aarch64: virtio_iommu_translate no mapping for 0x0 for sid=1024
qemu-system-aarch64: virtio-blk failed to set guest notifier (-22),
ensure -accel kvm is set.
qemu-system-aarch64: virtio_bus_start_ioeventfd: failed. Fallback to
userspace (slower).

Only happens with maxcpus=3. Note the virtio-blk-pci is not protected by
the vIOMMU in your case.

Thanks

Eric

>
>> ?
>>
>> My suspicion is that this will have started happening now that
>> we expose an SMMU with two-stage translation support to the guest
>> in the "virt" machine type (which we do not if you either
>> use virt-9.1 or in the v9.1.0 release).
>>
>> I've cc'd Eric (smmuv3 maintainer) and Mostafa (author of
>> the two-stage support).
>>
>>> qemu command which I use is as below:
>>>
>>> qemu-system-aarch64 -machine virt,kernel_irqchip=on,gic-version=3,iommu=smmuv3 \
>>> -kernel Image -initrd minifs.cpio.gz \
>>> -enable-kvm -net none -nographic -m 3G -smp 6 -cpu host \
>>> -append 'rdinit=init console=ttyAMA0 ealycon=pl0ll,0x90000000 maxcpus=3' \
>>> -device pcie-root-port,port=0x8,chassis=0,id=pci.0,bus=pcie.0,multifunction=on,addr=0x2 \
>>> -device pcie-root-port,port=0x9,chassis=1,id=pci.1,bus=pcie.0,addr=0x2.0x1 \
>>> -device virtio-blk-pci,drive=drive0,id=virtblk0,num-queues=8,packed=on,bus=pci.1 \
>>> -drive file=/home/boot.img,if=none,id=drive0,format=raw
>>>
>>> smmuv3 event 0x10 log:
>>> [...]
>>> [    1.962656] virtio-pci 0000:02:00.0: Adding to iommu group 0
>>> [    1.963150] virtio-pci 0000:02:00.0: enabling device (0000 -> 0002)
>>> [    1.964707] virtio_blk virtio0: 6/0/0 default/read/poll queues
>>> [    1.965759] virtio_blk virtio0: [vda] 2097152 512-byte logical blocks (1.07 GB/1.00 GiB)
>>> [    1.966934] arm-smmu-v3 9050000.smmuv3: event 0x10 received:
>>> [    1.967442] input: gpio-keys as /devices/platform/gpio-keys/input/input0
>>> [    1.967478] arm-smmu-v3 9050000.smmuv3:      0x0000020000000010
>>> [    1.968381] clk: Disabling unused clocks
>>> [    1.968677] arm-smmu-v3 9050000.smmuv3:      0x0000020000000000
>>> [    1.968990] PM: genpd: Disabling unused power domains
>>> [    1.969424] arm-smmu-v3 9050000.smmuv3:      0x0000000000000000
>>> [    1.969814] ALSA device list:
>>> [    1.970240] arm-smmu-v3 9050000.smmuv3:      0x0000000000000000
>>> [    1.970471]   No soundcards found.
>>> [    1.970902] arm-smmu-v3 9050000.smmuv3: event 0x10 received:
>>> [    1.971600] arm-smmu-v3 9050000.smmuv3:      0x0000020000000010
>>> [    1.971601] arm-smmu-v3 9050000.smmuv3:      0x0000020000000000
>>> [    1.971601] arm-smmu-v3 9050000.smmuv3:      0x0000000000000000
>>> [    1.971602] arm-smmu-v3 9050000.smmuv3:      0x0000000000000000
>>> [    1.971606] arm-smmu-v3 9050000.smmuv3: event 0x10 received:
>>> [    1.971607] arm-smmu-v3 9050000.smmuv3:      0x0000020000000010
>>> [    1.974202] arm-smmu-v3 9050000.smmuv3:      0x0000020000000000
>>> [    1.974634] arm-smmu-v3 9050000.smmuv3:      0x0000000000000000
>>> [    1.975005] Freeing unused kernel memory: 10112K
>>> [    1.975062] arm-smmu-v3 9050000.smmuv3:      0x0000000000000000
>>> [    1.975442] Run init as init process
>>>
>>> Another information is that if "maxcpus=3" is removed from the kernel command line,
>>> it will be OK.
>>>
>>> I am not sure if there is a bug about vsmmu. It will be very appreciated if anyone
>>> know this issue or can take a look at it.
>> thanks
>> -- PMM
>> .