iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops

The invalidate_range() notifier is called for any change to the address
space. Perform the required ATC invalidations.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20201106155048.997886-5-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c

@@ -177,6 +177,16 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
 	}
 }
 
+static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
+					 struct mm_struct *mm,
+					 unsigned long start, unsigned long end)
+{
+	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+
+	arm_smmu_atc_inv_domain(smmu_mn->domain, mm->pasid, start,
+				end - start + 1);
+}
+
 static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 {
 	struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
@@ -195,6 +205,7 @@ static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
 
 	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
+	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
 
 	smmu_mn->cleared = true;
 	mutex_unlock(&sva_lock);
@@ -206,6 +217,7 @@ static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
 }
 
 static struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
+	.invalidate_range	= arm_smmu_mm_invalidate_range,
 	.release		= arm_smmu_mm_release,
 	.free_notifier		= arm_smmu_mmu_notifier_free,
 };
@@ -278,8 +290,10 @@ static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
 	 * If we went through clear(), we've already invalidated, and no
 	 * new TLB entry can have been formed.
 	 */
-	if (!smmu_mn->cleared)
+	if (!smmu_mn->cleared) {
 		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
+		arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
+	}
 
 	/* Frees smmu_mn */
 	mmu_notifier_put(&smmu_mn->mn);

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -1524,6 +1524,20 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
 	size_t inval_grain_shift = 12;
 	unsigned long page_start, page_end;
 
+	/*
+	 * ATS and PASID:
+	 *
+	 * If substream_valid is clear, the PCIe TLP is sent without a PASID
+	 * prefix. In that case all ATC entries within the address range are
+	 * invalidated, including those that were requested with a PASID! There
+	 * is no way to invalidate only entries without PASID.
+	 *
+	 * When using STRTAB_STE_1_S1DSS_SSID0 (reserving CD 0 for non-PASID
+	 * traffic), translation requests without PASID create ATC entries
+	 * without PASID, which must be invalidated with substream_valid clear.
+	 * This has the unpleasant side-effect of invalidating all PASID-tagged
+	 * ATC entries within the address range.
+	 */
 	*cmd = (struct arm_smmu_cmdq_ent) {
 		.opcode			= CMDQ_OP_ATC_INV,
 		.substream_valid	= !!ssid,
@@ -1582,8 +1596,8 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
 	return arm_smmu_cmdq_issue_sync(master->smmu);
 }
 
-static int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
-				   int ssid, unsigned long iova, size_t size)
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+			    unsigned long iova, size_t size)
 {
 	int i;
 	unsigned long flags;

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h

@@ -695,6 +695,8 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			    struct arm_smmu_ctx_desc *cd);
 void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
 bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd);
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+			    unsigned long iova, size_t size);
 
 #ifdef CONFIG_ARM_SMMU_V3_SVA
 bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);