e9746a79b1
BugLink: https://bugs.launchpad.net/bugs/2081278 [ Upstream commit b5e86a95541cea737394a1da967df4cd4d8f7182 ] Queued invalidation wait descriptor status is volatile in that IOMMU hardware writes the data upon completion. Use READ_ONCE() to prevent compiler optimizations which ensures memory reads every time. As a side effect, READ_ONCE() also enforces strict types and may add an extra instruction. But it should not have negative performance impact since we use cpu_relax anyway and the extra time(by adding an instruction) may allow IOMMU HW request cacheline ownership easier. e.g. gcc 12.3 BEFORE: 81 38 ad de 00 00 cmpl $0x2,(%rax) AFTER (with READ_ONCE()) 772f: 8b 00 mov (%rax),%eax 7731: 3d ad de 00 00 cmp $0x2,%eax //status data is 32 bit Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20240607173817.3914600-1-jacob.jun.pan@linux.intel.com Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20240702130839.108139-2-baolu.lu@linux.intel.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Koichiro Den <koichiro.den@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com> |
||
|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| amd_iommu.c | ||
| amd_iommu.h | ||
| amd_iommu_debugfs.c | ||
| amd_iommu_init.c | ||
| amd_iommu_proto.h | ||
| amd_iommu_quirks.c | ||
| amd_iommu_types.h | ||
| amd_iommu_v2.c | ||
| arm-smmu-impl.c | ||
| arm-smmu-v3.c | ||
| arm-smmu.c | ||
| arm-smmu.h | ||
| dma-iommu.c | ||
| dmar.c | ||
| exynos-iommu.c | ||
| fsl_pamu.c | ||
| fsl_pamu.h | ||
| fsl_pamu_domain.c | ||
| fsl_pamu_domain.h | ||
| hyperv-iommu.c | ||
| intel-iommu-debugfs.c | ||
| intel-iommu.c | ||
| intel-pasid.c | ||
| intel-pasid.h | ||
| intel-svm.c | ||
| intel-trace.c | ||
| intel_irq_remapping.c | ||
| io-pgtable-arm-v7s.c | ||
| io-pgtable-arm.c | ||
| io-pgtable.c | ||
| iommu-debugfs.c | ||
| iommu-sysfs.c | ||
| iommu-traces.c | ||
| iommu.c | ||
| iova.c | ||
| ipmmu-vmsa.c | ||
| irq_remapping.c | ||
| irq_remapping.h | ||
| msm_iommu.c | ||
| msm_iommu.h | ||
| msm_iommu_hw-8xxx.h | ||
| mtk_iommu.c | ||
| mtk_iommu.h | ||
| mtk_iommu_v1.c | ||
| of_iommu.c | ||
| omap-iommu-debug.c | ||
| omap-iommu.c | ||
| omap-iommu.h | ||
| omap-iopgtable.h | ||
| qcom_iommu.c | ||
| rockchip-iommu.c | ||
| s390-iommu.c | ||
| tegra-gart.c | ||
| tegra-smmu.c | ||
| virtio-iommu.c | ||