diff options
| author | Will Deacon <will@kernel.org> | 2019-08-21 15:17:00 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2019-08-21 18:58:12 +0200 |
| commit | b5e86196b83fd68e065a7c811ab8925fb0dc3893 (patch) | |
| tree | ca99cf5850bc09b643f6afbc68d45b10ea5ec127 /drivers/iommu/arm-smmu-v3.c | |
| parent | iommu/arm-smmu-v3: Document ordering guarantees of command insertion (diff) | |
| download | linux-b5e86196b83fd68e065a7c811ab8925fb0dc3893.tar.xz linux-b5e86196b83fd68e065a7c811ab8925fb0dc3893.zip | |
iommu/arm-smmu-v3: Disable detection of ATS and PRI
Detecting the ATS capability of the SMMU at probe time introduces a
spinlock into the ->unmap() fast path, even when ATS is not actually
in use. Furthermore, the ATC invalidation that exists is broken, as it
occurs before invalidation of the main SMMU TLB which leaves a window
where the ATC can be repopulated with stale entries.
Given that ATS is both a new feature and a specialist sport, disable it
for now whilst we fix it properly in subsequent patches. Since PRI
requires ATS, disable that too.
Cc: <stable@vger.kernel.org>
Fixes: 9ce27afc0830 ("iommu/arm-smmu-v3: Add support for PCI ATS")
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/iommu/arm-smmu-v3.c')
| -rw-r--r-- | drivers/iommu/arm-smmu-v3.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 3402b1bc8e94..7a368059cd7d 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -3295,11 +3295,13 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu) } /* Boolean feature flags */ +#if 0 /* ATS invalidation is slow and broken */ if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI) smmu->features |= ARM_SMMU_FEAT_PRI; if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS) smmu->features |= ARM_SMMU_FEAT_ATS; +#endif if (reg & IDR0_SEV) smmu->features |= ARM_SMMU_FEAT_SEV; |