[PATCH v5 18/25] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops

[Jean-Philippe Brucker <jean-philippe@linaro.org>]

iommu-sva calls us when an mm is modified. Perform the required ATC
invalidations.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
v4->v5: more comments
---
 drivers/iommu/arm-smmu-v3.c | 70 ++++++++++++++++++++++++++++++-------
 1 file changed, 58 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 6640c2ac2a7c5..c4bffb14461aa 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2375,6 +2375,20 @@ 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,
@@ -2418,12 +2432,12 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
 	cmd->atc.size	= log2_span;
 }
 
-static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
+static int arm_smmu_atc_inv_master(struct arm_smmu_master *master, int ssid)
 {
 	int i;
 	struct arm_smmu_cmdq_ent cmd;
 
-	arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);
+	arm_smmu_atc_inv_to_cmd(ssid, 0, 0, &cmd);
 
 	for (i = 0; i < master->num_sids; i++) {
 		cmd.atc.sid = master->sids[i];
@@ -2934,7 +2948,7 @@ static void arm_smmu_disable_ats(struct arm_smmu_master *master)
 	 * ATC invalidation via the SMMU.
 	 */
 	wmb();
-	arm_smmu_atc_inv_master(master);
+	arm_smmu_atc_inv_master(master, 0);
 	atomic_dec(&smmu_domain->nr_ats_masters);
 }
 
@@ -3131,7 +3145,22 @@ arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 static void arm_smmu_mm_invalidate(struct device *dev, int pasid, void *entry,
 				   unsigned long iova, size_t size)
 {
-	/* TODO: Invalidate ATC */
+	int i;
+	struct arm_smmu_cmdq_ent cmd;
+	struct arm_smmu_cmdq_batch cmds = {};
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+
+	if (!master->ats_enabled)
+		return;
+
+	arm_smmu_atc_inv_to_cmd(pasid, iova, size, &cmd);
+
+	for (i = 0; i < master->num_sids; i++) {
+		cmd.atc.sid = master->sids[i];
+		arm_smmu_cmdq_batch_add(master->smmu, &cmds, &cmd);
+	}
+
+	arm_smmu_cmdq_batch_submit(master->smmu, &cmds);
 }
 
 static int arm_smmu_mm_attach(struct device *dev, int pasid, void *entry,
@@ -3168,26 +3197,43 @@ static void arm_smmu_mm_clear(struct device *dev, int pasid, void *entry)
 	 * for this ASID, so we need to do it manually.
 	 */
 	arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
-
-	/* TODO: invalidate ATC */
+	arm_smmu_atc_inv_domain(smmu_domain, pasid, 0, 0);
 }
 
 static void arm_smmu_mm_detach(struct device *dev, int pasid, void *entry,
 			       bool detach_domain, bool cleared)
 {
 	struct arm_smmu_ctx_desc *cd = entry;
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
 	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 
-	if (detach_domain) {
+	if (detach_domain)
 		arm_smmu_write_ctx_desc(smmu_domain, pasid, NULL);
 
-		if (!cleared)
-			/* See comment in arm_smmu_mm_clear() */
-			arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
-	}
+	/*
+	 * If we went through clear(), we've already invalidated, and no new TLB
+	 * entry can have been formed.
+	 */
+	if (cleared)
+		return;
+
+	if (detach_domain) {
+		/* See comment in arm_smmu_mm_clear() */
+		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
+		arm_smmu_atc_inv_domain(smmu_domain, pasid, 0, 0);
 
-	/* TODO: invalidate ATC */
+	} else if (master->ats_enabled) {
+		/*
+		 * There are more devices bound with this PASID in this domain,
+		 * so we cannot yet clear the PASID entry, and this device could
+		 * create new ATC entries. Invalidate the ATC for the sake of
+		 * it. On unbinding the last device we'll properly invalidate
+		 * all ATCs in the domain. Alternatively, an early detach_dev()
+		 * on this device will also flush the ATC.
+		 */
+		arm_smmu_atc_inv_master(master, pasid);
+	}
 }
 
 static void *arm_smmu_mm_alloc(struct mm_struct *mm)
-- 
2.26.0