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iommu/arm-smmu-v3: Invalidate ATC when detaching a device

We make the invalid assumption in arm_smmu_detach_dev() that the ATC is clear after calling pci_disable_ats(). For one thing, only enabling the PCIe ATS capability constitutes an implicit invalidation event, so the comment was wrong. More importantly, the ATS capability isn't necessarily disabled by pci_disable_ats() in a PF, if the associated VFs have ATS enabled. Explicitly invalidate all ATC entries in arm_smmu_detach_dev(). The endpoint cannot form new ATC entries because STE.EATS is clear.

Jean-Philippe Brucker committed 7 years ago

Commit 8dd8f001 parent 900a85c1 file · +4 −1Browse files

Unified · Split

drivers/iommu/arm-smmu-v3.c+4−1
@@ -1892,9 +1892,13 @@ static int arm_smmu_enable_ats(struct arm_smmu_master *master) · 1891 unmodified lines
1892 1892
1893static void arm_smmu_disable_ats(struct arm_smmu_master *master)1893static void arm_smmu_disable_ats(struct arm_smmu_master *master)
1894{1894{
1895 struct arm_smmu_cmdq_ent cmd;
1896
1895 if (!master->ats_enabled || !dev_is_pci(master->dev))1897 if (!master->ats_enabled || !dev_is_pci(master->dev))
1896 return;1898 return;
1897 1899
1900 arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);
1901 arm_smmu_atc_inv_master(master, &cmd);
1898 pci_disable_ats(to_pci_dev(master->dev));1902 pci_disable_ats(to_pci_dev(master->dev));
1899 master->ats_enabled = false;1903 master->ats_enabled = false;
1900}1904}
@@ -1914,7 +1918,6 @@ static void arm_smmu_detach_dev(struct arm_smmu_master *master) · 13 unmodified lines
1914 master->domain = NULL;1918 master->domain = NULL;
1915 arm_smmu_install_ste_for_dev(master);1919 arm_smmu_install_ste_for_dev(master);
1916 1920
1917 /* Disabling ATS invalidates all ATC entries */
1918 arm_smmu_disable_ats(master);1921 arm_smmu_disable_ats(master);
1919}1922}
1920 1923