openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

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: 9ce27afc08 ("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>
This commit is contained in:
Will Deacon 2019-08-21 14:17:00 +01:00
parent 05cbaf4ddd
commit b5e86196b8
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/iommu/arm-smmu-v3.c
View File

@ -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;