Hi Tomasz On 27/09/2017 13:07, Tomasz Nowicki wrote: > Hi Eric, > > Out of curiosity, I compared your SMMUv3 full emulation against > virtio-iommu. For virtio-net device behind the virtio-iommu I get 50% > performance of what I can get for SMMUv3 emulation. > > Do you have similar observations? Since there is no need to emulate HW > behaviour in QEMU I expected virtio-iommu to be faster. I will run some > more benchmarks.
No I don't have formal comparative figures at the moment. Benchmarking is also on the top of my todo list though. One reason could be that virtio-iommu sends requests for each map operations whereas this does not happen for vsmmuv3 (in non caching mode). You could try to turn the vsmmuv3 caching-mode option and I guess you should have more similar perf figures between virtio-iommu and vsmuv3. Thanks Eric > > Thanks, > Tomasz > > On 19.09.2017 09:46, Eric Auger wrote: >> This series implements the virtio-iommu device. >> >> This v4 is an upgrade to v0.4 spec [1] and applies on QEMU v2.10.0. >> - probe request support although no reserved region is returned at >> the moment >> - unmap semantics less strict, as specified in v0.4 >> - device registration, attach/detach revisited >> - split into smaller patches to ease review >> - propose a way to inform the IOMMU mr about the page_size_mask >> of underlying HW IOMMU, if any >> - remove warning associated with the translation of the MSI doorbell >> >> The device gets instantiated using the "-device virtio-iommu-device" >> option. It currently works with ARM virt machine only, as the machine >> must handle the dt binding between the virtio-mmio "iommu" node and >> the PCI host bridge node. >> >> The associated VHOST/VFIO adaptation is available on the branch >> below but is not officially delivered as part of this series. >> >> Best Regards >> >> Eric >> >> This series can be found at: >> https://github.com/eauger/qemu/tree/v2.10.0-virtio-iommu-v4 >> >> References: >> [1] [RFC] virtio-iommu version 0.4 >> git://linux-arm.org/virtio-iommu.git branch viommu/v0.4 >> >> Testing: >> - guest kernel with v0.4 virtio-iommu driver (4kB page) >> - tested with guest using virtio-pci-net and vhost-net >> (,vhost=on/off,iommu_platform,disable-modern=off,disable-legacy=on ) >> - tested with VFIO and guest assigned with 2 VFs >> - tested with DPDK on guest with 2 assigned VFs >> >> Not tested: >> - hot-plug/hot-unplug of EP: not implemented >> >> History: >> v2-> v4: >> - see above >> >> v2 -> v3: >> - rebase on top of 2.10-rc0 and especially >> [PATCH qemu v9 0/2] memory/iommu: QOM'fy IOMMU MemoryRegion >> - add mutex init >> - fix as->mappings deletion using g_tree_ref/unref >> - when a dev is attached whereas it is already attached to >> another address space, first detach it >> - fix some error values >> - page_sizes = TARGET_PAGE_MASK; >> - I haven't changed the unmap() semantics yet, waiting for the >> next virtio-iommu spec revision. >> >> v1 -> v2: >> - fix redifinition of viommu_as typedef >> >> Eric Auger (16): >> update-linux-headers: import virtio_iommu.h >> linux-headers: Update for virtio-iommu >> virtio-iommu: add skeleton >> virtio-iommu: Decode the command payload >> virtio-iommu: Add the iommu regions >> virtio-iommu: Register attached devices >> virtio-iommu: Implement attach/detach command >> virtio-iommu: Implement map/unmap >> virtio-iommu: Implement translate >> virtio-iommu: Implement probe request >> hw/arm/virt: Add 2.11 machine type >> hw/arm/virt: Add virtio-iommu to the virt board >> memory.h: Add set_page_size_mask IOMMUMemoryRegion callback >> hw/vfio/common: Set the IOMMUMemoryRegion supported page sizes >> virtio-iommu: Implement set_page_size_mask >> hw/vfio/common: Do not print error when viommu translates into an mmio >> region >> >> hw/arm/virt.c | 115 +++- >> hw/vfio/common.c | 7 +- >> hw/virtio/Makefile.objs | 1 + >> hw/virtio/trace-events | 24 + >> hw/virtio/virtio-iommu.c | 923 >> ++++++++++++++++++++++++++ >> include/exec/memory.h | 4 + >> include/hw/arm/virt.h | 5 + >> include/hw/vfio/vfio-common.h | 1 + >> include/hw/virtio/virtio-iommu.h | 61 ++ >> include/standard-headers/linux/virtio_ids.h | 1 + >> include/standard-headers/linux/virtio_iommu.h | 177 +++++ >> linux-headers/linux/virtio_iommu.h | 1 + >> scripts/update-linux-headers.sh | 3 + >> 13 files changed, 1312 insertions(+), 11 deletions(-) >> create mode 100644 hw/virtio/virtio-iommu.c >> create mode 100644 include/hw/virtio/virtio-iommu.h >> create mode 100644 include/standard-headers/linux/virtio_iommu.h >> create mode 100644 linux-headers/linux/virtio_iommu.h >> >