search for: vsmmuv3

...ugh, missing page fault support and I'd like to rework the > PASID model a bit, but table descriptors p.24-26 for both Arm > SMMUv2 and SMMUv3.) > > http://jpbrucker.net/virtio-iommu/spec-table/diffs/virtio-iommu-pdf-diff-v0.9-v0.10.dev03.pdf > > [2] [RFC v2 00/28] vSMMUv3/pSMMUv3 2 stage VFIO integration > https://www.mail-archive.com/qemu-devel at nongnu.org/msg562369.html

...you think? >> >> Is it true that SMMUv3 is fundmentally slow at the architecture level >> and so a PV interface will always scale better until >> a new hardware interface is designed? > > As far as I understand the figures above correspond to vhost-iommu > against vsmmuv3. In the 2 cases the guest owns stage1 tables so the > difference comes from the IOTLB invalidation handling. With vhost we > avoid a kernel <-> userspace round trip which may mostly explain the > difference. > > About SMMUv3 issues I already reported one big limitation with re...

...ation? > > Eric what do you think? > > Is it true that SMMUv3 is fundmentally slow at the architecture level > and so a PV interface will always scale better until > a new hardware interface is designed? As far as I understand the figures above correspond to vhost-iommu against vsmmuv3. In the 2 cases the guest owns stage1 tables so the difference comes from the IOTLB invalidation handling. With vhost we avoid a kernel <-> userspace round trip which may mostly explain the difference. About SMMUv3 issues I already reported one big limitation with respect to hugepage invalid...

On Tue, Nov 27, 2018 at 05:55:20PM +0000, Jean-Philippe Brucker wrote: > On 23/11/2018 21:56, Michael S. Tsirkin wrote: > >> +config VIRTIO_IOMMU > >> + bool "Virtio IOMMU driver" > >> + depends on VIRTIO=y > >> + select IOMMU_API > >> + select INTERVAL_TREE > >> + select ARM_DMA_USE_IOMMU if ARM > >> + help > >>

...ble sharing draft (Very rough, missing page fault support and I'd like to rework the PASID model a bit, but table descriptors p.24-26 for both Arm SMMUv2 and SMMUv3.) http://jpbrucker.net/virtio-iommu/spec-table/diffs/virtio-iommu-pdf-diff-v0.9-v0.10.dev03.pdf [2] [RFC v2 00/28] vSMMUv3/pSMMUv3 2 stage VFIO integration https://www.mail-archive.com/qemu-devel at nongnu.org/msg562369.html