diff options
| author | Will Deacon <will@kernel.org> | 2019-08-21 14:17:00 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-05 15:12:23 +0200 |
| commit | 4cc03cdf28fbdc80783cd28411398ea16a78760f (patch) | |
| tree | 07ea75bd43f208501b1ae55b3f7190b316053d1b | |
| parent | 922b0e17473bb5577331cd4b42891bbb54dc8f60 (diff) | |
iommu/arm-smmu-v3: Disable detection of ATS and PRI
commit b5e86196b83fd68e065a7c811ab8925fb0dc3893 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 c5c93e48b4db..d1ebe5ce3e47 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -2843,11 +2843,13 @@ 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; |