iommu/arm-smmu: Fix for ThunderX erratum #27704
The goal of erratum #27704 workaround was to make sure that ASIDs and VMIDs
are unique across all SMMU instances on affected Cavium systems.
Currently, the workaround code partitions ASIDs and VMIDs by increasing
global cavium_smmu_context_count which in turn becomes the base ASID and VMID
value for the given SMMU instance upon the context bank initialization.
For systems with multiple SMMU instances this approach implies the risk
of crossing 8-bit ASID, like for 1-socket CN88xx capable of 4 SMMUv2,
128 context banks each:
SMMU_0 (0-127 ASID RANGE)
SMMU_1 (127-255 ASID RANGE)
SMMU_2 (256-383 ASID RANGE) <--- crossing 8-bit ASID
SMMU_3 (384-511 ASID RANGE) <--- crossing 8-bit ASID
Since now we use 8-bit ASID (SMMU_CBn_TCR2.AS = 0) we effectively misconfigure
ASID[15:8] bits of SMMU_CBn_TTBRm register for SMMU_2/3. Moreover, we still
assume non-zero ASID[15:8] bits upon context invalidation. In the end,
except SMMU_0/1 devices all other devices under other SMMUs will fail on guest
power off/on. Since we try to invalidate TLB with 16-bit ASID but we actually
have 8-bit zero padded 16-bit entry.
This patch adds 16-bit ASID support for stage-1 AArch64 contexts so that
we use ASIDs consistently for all SMMU instances.
Change-Id: I7949517de95b4a6b28125e8f3d18b453168658b2
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@cavium.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: 3677a649a751c8f061ba379a98c369473ccac980
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
1 file changed