[PATCH 16/27] iommu/arm-smmu-v3: Keep track of valid CD entries in the cd_table

[Jason Gunthorpe]

We no longer need a master->sva_enable to control what attaches are
allowed.

Instead keep track inside the cd_table how many valid CD entries exist,
and if the RID has a valid entry.

Replace all the attach focused master->sva_enabled tests with a check if
the CD has valid entries (or not). If there are any valid entries then the
CD table must be currently programmed to the STE.

Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
---
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  5 +---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 26 ++++++++++---------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   | 10 +++++++
 3 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 702a6ef9df8a22..042daaef0c9703 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -421,9 +421,6 @@ static struct iommu_sva *__arm_smmu_sva_bind(struct device *dev,
 	if (!smmu_domain || smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
 		return ERR_PTR(-ENODEV);
 
-	if (!master || !master->sva_enabled)
-		return ERR_PTR(-ENODEV);
-
 	/* If bind() was already called for this {dev, mm} pair, reuse it. */
 	list_for_each_entry(bond, &master->bonds, list) {
 		if (bond->mm == mm) {
@@ -643,7 +640,7 @@ static int arm_smmu_sva_set_dev_pasid(struct iommu_domain *domain,
 	struct mm_struct *mm = domain->mm;
 	struct arm_smmu_cd target;
 
-	if (mm->pasid != id)
+	if (mm->pasid != id || !master->cd_table.used_sid)
 		return -EINVAL;
 
 	if (!arm_smmu_get_cd_ptr(master, id))
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 59de4f5302c57d..a3d2914bcc36ae 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1154,8 +1154,19 @@ void arm_smmu_write_cd_entry(struct arm_smmu_master *master, int ssid,
 			     const struct arm_smmu_cd *target)
 {
 	struct arm_smmu_cd target_used;
+	bool cur_valid = cdptr->data[0] & cpu_to_le64(CTXDESC_CD_0_V);
+	bool target_valid = target->data[0] & cpu_to_le64(CTXDESC_CD_0_V);
 	int i;
 
+	if (cur_valid != target_valid) {
+		if (cur_valid)
+			master->cd_table.used_ssids--;
+		else
+			master->cd_table.used_ssids++;
+	}
+	if (ssid == IOMMU_NO_PASID)
+		master->cd_table.used_sid = target_valid;
+
 	arm_smmu_get_cd_used(target, &target_used);
 	/* Masks in arm_smmu_get_cd_used() are up to date */
 	for (i = 0; i != ARRAY_SIZE(target->data); i++)
@@ -2637,16 +2648,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	master = dev_iommu_priv_get(dev);
 	smmu = master->smmu;
 
-	/*
-	 * Checking that SVA is disabled ensures that this device isn't bound to
-	 * any mm, and can be safely detached from its old domain. Bonds cannot
-	 * be removed concurrently since we're holding the group mutex.
-	 */
-	if (arm_smmu_master_sva_enabled(master)) {
-		dev_err(dev, "cannot attach - SVA enabled\n");
-		return -EBUSY;
-	}
-
 	mutex_lock(&smmu_domain->init_mutex);
 
 	if (!smmu_domain->smmu) {
@@ -2662,7 +2663,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		cdptr = arm_smmu_get_cd_ptr(master, IOMMU_NO_PASID);
 		if (!cdptr)
 			return -ENOMEM;
-	}
+	} else if (arm_smmu_ssids_in_use(&master->cd_table))
+		return -EBUSY;
 
 	/*
 	 * Prevent arm_smmu_share_asid() from trying to change the ASID
@@ -2732,7 +2734,7 @@ static int arm_smmu_attach_dev_ste(struct device *dev,
 {
 	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
 
-	if (arm_smmu_master_sva_enabled(master))
+	if (arm_smmu_ssids_in_use(&master->cd_table))
 		return -EBUSY;
 
 	/*
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 8349649654e2c9..ae8b2d8c7192f6 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -602,11 +602,21 @@ struct arm_smmu_ctx_desc_cfg {
 	dma_addr_t			cdtab_dma;
 	struct arm_smmu_l1_ctx_desc	*l1_desc;
 	unsigned int			num_l1_ents;
+	unsigned int			used_ssids;
+	bool				used_sid;
 	u8				s1fmt;
 	/* log2 of the maximum number of CDs supported by this table */
 	u8				s1cdmax;
 };
 
+/* True if the cd table has SSIDS > 0 in use. */
+static inline bool arm_smmu_ssids_in_use(struct arm_smmu_ctx_desc_cfg *cd_table)
+{
+	if (cd_table->used_sid)
+		return cd_table->used_ssids > 1;
+	return cd_table->used_ssids;
+}
+
 struct arm_smmu_s2_cfg {
 	u16				vmid;
 };
-- 
2.42.0