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Diffstat (limited to 'results/classifier/deepseek-1/output/device/1851664')
| -rw-r--r-- | results/classifier/deepseek-1/output/device/1851664 | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/results/classifier/deepseek-1/output/device/1851664 b/results/classifier/deepseek-1/output/device/1851664 new file mode 100644 index 00000000..b127a3c6 --- /dev/null +++ b/results/classifier/deepseek-1/output/device/1851664 @@ -0,0 +1,38 @@ + +qemu-system-x86_64: "VFIO_MAP_DMA : -28" error when we attache 6 VF's to guest machine + +We are trying to attach 6 VF's to the guest machine on 4.1.1 qemu emulator. +We are observing "VFIO_MAP_DMA : -28" error. + +We are using w-bits=48 bits while lunching VM. + +Please provide information how you started QEMU, and some information about your PCI device (e.g. the output of lspci). + +qemu-system-x86_64 -name guest=fedora24 -machine q35,accel=kvm,kernel-irqchip=split \ + -enable-kvm \ + -m 4G \ + -smp 8,sockets=1,cores=8,threads=1 \ + -device intel-iommu,intremap=on,caching-mode=on,aw-bits=48 \ + -drive file=<OS_IMAGE_FILE>,format=raw \ + -device ioh3420,id=pcie.1,chassis=1 \ + -device virtio-net-pci,bus=pcie.1,disable-legacy=on,disable-modern=off,iommu_platform=on,ats=on,netdev=net0 \ + -netdev user,id=net0,hostfwd=tcp::1111-:22\ + -device vfio-pci,host=3f:02.1 \ + -device vfio-pci,host=3f:02.2 \ + -device vfio-pci,host=3f:02.3 \ + -device vfio-pci,host=3f:02.4 \ + -device vfio-pci,host=3d:02.4 \ + -device vfio-pci,host=3d:02.5 \ + -device vfio-pci,host=3d:02.6 \ + -nographic + +Please find the above qemu command to lunch guest machine + +Presumably w-bits (aw-bits?) implies using intel-iommu, there's a opportunity for the vfio iommu backend to return -ENOSPC (-28) if we exceed the default number of in-flight DMA mappings per container. The default limit is 65535. You can try increasing this by changing the dma_entry_limit module option on the vfio_iommu_type1 module. Note that in a typical vIOMMU config there's a container per device, so the number of VFs attached is possibly not a factor. It is however a lot of DMA mappings for a single device if this is the issue and you'd generally want to boot the guest with iommu=pt in order to have reasonable assigned device performance with a vIOMMU, which would also greatly reduce the number of mappings. + +After increasing dma_entry_limit limit no issue observed. + +But ideal senario device is getting hung and recovery happening only with host hard rebooting. + +[Expired for QEMU because there has been no activity for 60 days.] + |