Re: [RFC v6 00/24] vSMMUv3/pSMMUv3 2 stage VFIO integration

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

Hi Shameer,

On 3/25/20 12:35 PM, Shameerali Kolothum Thodi wrote:
> Hi Eric,
> 
>> -----Original Message-----
>> From: Eric Auger [mailto:eric.auger@redhat.com]
>> Sent: 20 March 2020 16:58
>> To: eric.auger.pro@gmail.com; eric.auger@redhat.com;
>> qemu-devel@nongnu.org; qemu-arm@nongnu.org; peter.maydell@linaro.org;
>> mst@redhat.com; alex.williamson@redhat.com;
>> jacob.jun.pan@linux.intel.com; yi.l.liu@intel.com
>> Cc: peterx@redhat.com; jean-philippe@linaro.org; will@kernel.org;
>> tnowicki@marvell.com; Shameerali Kolothum Thodi
>> <shameerali.kolothum.thodi@huawei.com>; zhangfei.gao@foxmail.com;
>> zhangfei.gao@linaro.org; maz@kernel.org; bbhushan2@marvell.com
>> Subject: [RFC v6 00/24] vSMMUv3/pSMMUv3 2 stage VFIO integration
>>
>> Up to now vSMMUv3 has not been integrated with VFIO. VFIO
>> integration requires to program the physical IOMMU consistently
>> with the guest mappings. However, as opposed to VTD, SMMUv3 has
>> no "Caching Mode" which allows easy trapping of guest mappings.
>> This means the vSMMUV3 cannot use the same VFIO integration as VTD.
>>
>> However SMMUv3 has 2 translation stages. This was devised with
>> virtualization use case in mind where stage 1 is "owned" by the
>> guest whereas the host uses stage 2 for VM isolation.
>>
>> This series sets up this nested translation stage. It only works
>> if there is one physical SMMUv3 used along with QEMU vSMMUv3 (in
>> other words, it does not work if there is a physical SMMUv2).
> 
> I was testing this series on one of our hardware board with SMMUv3. I did
> observe an issue while trying to bring up Guest with and without the vsmmuV3.
> 
> Steps are like below,
> 
> 1. start a guest with "iommu=smmuv3" and a n/w vf device.
> 
> 2.Exit the VM.
> 
> 3. start the guest again without "iommu=smmuv3"
> 
> This time qemu crashes with,
> 
> [ 0.447830] hns3 0000:00:01.0: enabling device (0000 -> 0002)
> /home/shameer/qemu-eric/qemu/hw/vfio/pci.c:2851:vfio_dma_fault_notifier_handler:
> Object 0xaaaaeeb47c00 is not an instance of type
> qemu:iommu-memory-region
> ./qemu_run-vsmmu-hns: line 9: 13609 Aborted                 (core
> dumped) ./qemu-system-aarch64-vsmmuv3v10 -machine
> virt,kernel_irqchip=on,gic-version=3 -cpu host -smp cpus=1 -kernel
> Image-ericv10-uacce -initrd rootfs-iperf.cpio -bios
> QEMU_EFI_Dec2018.fd -device vfio-pci,host=0000:7d:02.1 -net none -m
> 4096 -nographic -D -d -enable-kvm -append "console=ttyAMA0
> root=/dev/vda -m 4096 rw earlycon=pl011,0x9000000"
> 
> And you can see that host kernel receives smmuv3 C_BAD_STE event,
> 
> [10499.379288] vfio-pci 0000:7d:02.1: enabling device (0000 -> 0002)
> [10501.943881] arm-smmu-v3 arm-smmu-v3.2.auto: event 0x04 received:
> [10501.943884] arm-smmu-v3 arm-smmu-v3.2.auto: 0x00007d1100000004
> [10501.943886] arm-smmu-v3 arm-smmu-v3.2.auto: 0x0000100800000080
> [10501.943887] arm-smmu-v3 arm-smmu-v3.2.auto: 0x00000000fe040000
> [10501.943889] arm-smmu-v3 arm-smmu-v3.2.auto: 0x000000007e04c440
> 
> So I suspect we didn't clear nested stage configuration and that affects the 
> translation in the second run. I tried to issue(force) a vfio_detach_pasid_table() but 
> that didn't solve the problem.
> 
> May be I am missing something. Could you please take a look and let me know.

Sure, I will try to reproduce on my end. Thank you for the bug report!

Best Regards

Eric
> 
> Thanks,
> Shameer
> 
>> - We force the host to use stage 2 instead of stage 1, when we
>>   detect a vSMMUV3 is behind a VFIO device. For a VFIO device
>>   without any virtual IOMMU, we still use stage 1 as many existing
>>   SMMUs expect this behavior.
>> - We use PCIPASIDOps to propage guest stage1 config changes on
>>   STE (Stream Table Entry) changes.
>> - We implement a specific UNMAP notifier that conveys guest
>>   IOTLB invalidations to the host
>> - We register MSI IOVA/GPA bindings to the host so that this latter
>>   can build a nested stage translation
>> - As the legacy MAP notifier is not called anymore, we must make
>>   sure stage 2 mappings are set. This is achieved through another
>>   prereg memory listener.
>> - Physical SMMU stage 1 related faults are reported to the guest
>>   via en eventfd mechanism and exposed trhough a dedicated VFIO-PCI
>>   region. Then they are reinjected into the guest.
>>
>> Best Regards
>>
>> Eric
>>
>> This series can be found at:
>> https://github.com/eauger/qemu/tree/v4.2.0-2stage-rfcv6
>>
>> Kernel Dependencies:
>> [1] [PATCH v10 00/11] SMMUv3 Nested Stage Setup (VFIO part)
>> [2] [PATCH v10 00/13] SMMUv3 Nested Stage Setup (IOMMU part)
>> branch at:
>> https://github.com/eauger/linux/tree/will-arm-smmu-updates-2stage-v10
>>
>> History:
>>
>> v5 -> v6:
>> - just rebase work
>>
>> v4 -> v5:
>> - Use PCIPASIDOps for config update notifications
>> - removal of notification for MSI binding which is not needed
>>   anymore
>> - Use a single fault region
>> - use the specific interrupt index
>>
>> v3 -> v4:
>> - adapt to changes in uapi (asid cache invalidation)
>> - check VFIO_PCI_DMA_FAULT_IRQ_INDEX is supported at kernel level
>>   before attempting to set signaling for it.
>> - sync on 5.2-rc1 kernel headers + Drew's patch that imports sve_context.h
>> - fix MSI binding for MSI (not MSIX)
>> - fix mingw compilation
>>
>> v2 -> v3:
>> - rework fault handling
>> - MSI binding registration done in vfio-pci. MSI binding tear down called
>>   on container cleanup path
>> - leaf parameter propagated
>>
>> v1 -> v2:
>> - Fixed dual assignment (asid now correctly propagated on TLB invalidations)
>> - Integrated fault reporting
>>
>>
>> Eric Auger (23):
>>   update-linux-headers: Import iommu.h
>>   header update against 5.6.0-rc3 and IOMMU/VFIO nested stage APIs
>>   memory: Add IOMMU_ATTR_VFIO_NESTED IOMMU memory region
>> attribute
>>   memory: Add IOMMU_ATTR_MSI_TRANSLATE IOMMU memory region
>> attribute
>>   memory: Introduce IOMMU Memory Region inject_faults API
>>   memory: Add arch_id and leaf fields in IOTLBEntry
>>   iommu: Introduce generic header
>>   vfio: Force nested if iommu requires it
>>   vfio: Introduce hostwin_from_range helper
>>   vfio: Introduce helpers to DMA map/unmap a RAM section
>>   vfio: Set up nested stage mappings
>>   vfio: Pass stage 1 MSI bindings to the host
>>   vfio: Helper to get IRQ info including capabilities
>>   vfio/pci: Register handler for iommu fault
>>   vfio/pci: Set up the DMA FAULT region
>>   vfio/pci: Implement the DMA fault handler
>>   hw/arm/smmuv3: Advertise MSI_TRANSLATE attribute
>>   hw/arm/smmuv3: Store the PASID table GPA in the translation config
>>   hw/arm/smmuv3: Fill the IOTLBEntry arch_id on NH_VA invalidation
>>   hw/arm/smmuv3: Fill the IOTLBEntry leaf field on NH_VA invalidation
>>   hw/arm/smmuv3: Pass stage 1 configurations to the host
>>   hw/arm/smmuv3: Implement fault injection
>>   hw/arm/smmuv3: Allow MAP notifiers
>>
>> Liu Yi L (1):
>>   pci: introduce PCIPASIDOps to PCIDevice
>>
>>  hw/arm/smmuv3.c                 | 189 ++++++++++--
>>  hw/arm/trace-events             |   3 +-
>>  hw/pci/pci.c                    |  34 +++
>>  hw/vfio/common.c                | 506
>> +++++++++++++++++++++++++-------
>>  hw/vfio/pci.c                   | 267 ++++++++++++++++-
>>  hw/vfio/pci.h                   |   9 +
>>  hw/vfio/trace-events            |   9 +-
>>  include/exec/memory.h           |  49 +++-
>>  include/hw/arm/smmu-common.h    |   1 +
>>  include/hw/iommu/iommu.h        |  28 ++
>>  include/hw/pci/pci.h            |  11 +
>>  include/hw/vfio/vfio-common.h   |  16 +
>>  linux-headers/COPYING           |   2 +
>>  linux-headers/asm-x86/kvm.h     |   1 +
>>  linux-headers/linux/iommu.h     | 375 +++++++++++++++++++++++
>>  linux-headers/linux/vfio.h      | 109 ++++++-
>>  memory.c                        |  10 +
>>  scripts/update-linux-headers.sh |   2 +-
>>  18 files changed, 1478 insertions(+), 143 deletions(-)
>>  create mode 100644 include/hw/iommu/iommu.h
>>  create mode 100644 linux-headers/linux/iommu.h
>>
>> --
>> 2.20.1
> 
>