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This makes sense when installing a guest STE, since a vSID must be > present and given to the kernel during the vDEVICE allocation. > > But, when CR0.SMMUEN is disabled, VM doesn't really need a vSID to program > the vSMMU behavior as GBPA will take effect, in which case the vSTE in the > nested domain could have carried the bypass or abort configuration in GBPA > register. Thus, having such a hard requirement doesn't work well for GBPA. > > Skip vmaster allocation in arm_smmu_attach_prepare_vmaster() for an abort > or bypass vSTE. Note that device on this attachment won't report vevents. > > Update the uAPI doc accordingly. > > Tested-by: Shameer Kolothum > Signed-off-by: Nicolin Chen > --- > > Changelog > v2 > * Add Tested-by from Shameer > * Skip vmaster allocation instead of bypassing vsid=0 > * Revise the uAPI doc to note a corner case when CR0.SMMUEN=1 > > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 13 ++++++++++++- > include/uapi/linux/iommufd.h | 9 +++++++++ > 2 files changed, 21 insertions(+), 1 deletion(-) Reviewed-by: Jason Gunthorpe Will, I will grab this in a few days unless you want it in your tree Thanks, Jason