When IOMMU and vhost are enabled together, QEMU tracks IOTLB or Device-TLB unmap events depending on whether Device-TLB is enabled. But even if Device-TLB and PCI ATS is enabled, the guest can reject to use it. For example, this situation appears when Windows Server 2022 is running with intel-iommu with device-iotlb=on and virtio-net-pci with vhost=on. The guest implies that no address translation info cached in device IOTLB and doesn't send device IOTLB invalidation commands. So, it leads to irrelevant address translations in vhost-net in the host kernel. Therefore network frames from the guest in host tap interface contains wrong payload data.
This series adds checking of ATS state for proper unmap flag register (IOMMU_NOTIFIER_UNMAP or IOMMU_NOTIFIER_DEVIOTLB_UNMAP). Tested on Windows Server 2022, Windows 11 and Fedora guests with -device virtio-net-pci,bus=pci.3,netdev=nd0,iommu_platform=on,ats=on -netdev tap,id=nd0,ifname=tap1,script=no,downscript=no,vhost=on -device intel-iommu,intremap=on,eim=on,device-iotlb=on/off Tested on Fedora guest with -device virtio-iommu Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2001312 v5: add vhost_toggle_device_iotlb to vhost-stub v4: call vhost_toggle_device_iotlb regardless of vhost backend, move vhost_started check to generic part v3: call virtio_pci_ats_ctrl_trigger directly, remove IOMMU_NOTIFIER_UNMAP fallbacks v2: remove memory_region_iommu_notify_flags_changed, move trigger to VirtioDeviceClass, use vhost_ops, use device_iotlb name Viktor Prutyanov (2): vhost: register and change IOMMU flag depending on Device-TLB state virtio-net: pass Device-TLB enable/disable events to vhost hw/net/virtio-net.c | 1 + hw/virtio/vhost-stub.c | 4 ++++ hw/virtio/vhost.c | 38 ++++++++++++++++++++++++++------------ include/hw/virtio/vhost.h | 1 + 4 files changed, 32 insertions(+), 12 deletions(-) -- 2.21.0
