iommu/arm-smmu-v3: Add support for VHE

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ARMv8.1 extensions added Virtualization Host Extensions (VHE), which allow
to run a host kernel at EL2. When using normal DMA, Device and CPU address
spaces are dissociated, and do not need to implement the same
capabilities, so VHE hasn't been used in the SMMU until now.

With shared address spaces however, ASIDs are shared between MMU and SMMU,
and broadcast TLB invalidations issued by a CPU are taken into account by
the SMMU. TLB entries on both sides need to have identical exception level
in order to be cleared with a single invalidation.

When the CPU is using VHE, enable VHE in the SMMU for all STEs. Normal DMA
mappings will need to use TLBI_EL2 commands instead of TLBI_NH, but
shouldn't be otherwise affected by this change.

Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20210122151054.2833521-4-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>

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Jean-Philippe Brucker 2021-01-22 16:10:56 +01:00 • committed by Will Deacon

parent 51d113c3be

commit 9111aebf77

2 changed files with 28 additions and 7 deletions

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32

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

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3

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h

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