[PATCH v3 0/8] Refactor the SMMU's CD table ownership

[PATCH v3 0/8] Refactor the SMMU's CD table ownership

[Michael Shavit]

Hi all,

This series refactors stage 1 domains so that they describe a single CD
entry. These entries are now inserted into a CD table that is owned by
the arm_smmu_master instead of the domain.
This is conceptually cleaner and unblocks other features, such as
attaching domains with PASID (for unmanaged/dma domains).

This patch series was originally part of a larger patch series that
implemented the set_dev_pasid callback for non-SVA domains but is now
split into a distinct series.

This patch series is also available on gerrit with Jean's SMMU test
engine patches cherry-picked on top for testing:
https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/24742/3

Thanks,
Michael Shavit

Changes in v3:
- Add a helper to write a CD to all masters that a domain is attached
  to.
- Fixed an issue where an arm_smmu_write_ctx_desc error return wasn't
  correctly handled by its caller.
- Flip the cd_table.installed bit back off when table is detached
- re-order the commit later in the series since flipping the installed
  bit to off isn't obvious when the cd_table is still shared by multiple
  masters.
- Link to v2: https://lore.kernel.org/all/20230731104833.800114-1-mshavit@google.com/

Changes in v2:
- Allocate CD table when it's first needed instead of on probe.
- Minor changes
- Added commit to rename remaining usages of cdcfg to cd_table
- Link to v1: https://lore.kernel.org/all/20230727182647.4106140-1-mshavit@google.com/

Changes in v1:
- Replace s1_cfg with arm_smmu_ctx_desc_cfg representing the CD table
- Assume that the CD table is owned by the SMMU master for most
  operations. This is forward-compatible with the nested patch series as
  these operations wouldn't be called when the installed CD table comes
  from nested domains.
- Split off as a distinct patch series from https://lore.kernel.org/all/20230621063825.268890-1-mshavit@google.com/

Michael Shavit (8):
  iommu/arm-smmu-v3: Move ctx_desc out of s1_cfg
  iommu/arm-smmu-v3: Replace s1_cfg with cdtab_cfg
  iommu/arm-smmu-v3: Encapsulate ctx_desc_cfg init in alloc_cd_tables
  iommu/arm-smmu-v3: move stall_enabled to the cd table
  iommu/arm-smmu-v3: Refactor write_ctx_desc
  iommu/arm-smmu-v3: Move CD table to arm_smmu_master
  iommu/arm-smmu-v3: Skip cd sync if CD table isn't active
  iommu/arm-smmu-v3: Rename cdcfg to cd_table

 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  33 ++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 217 ++++++++----------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  21 +-
 3 files changed, 139 insertions(+), 132 deletions(-)


base-commit: 57012c57536f8814dec92e74197ee96c3498d24e
-- 
2.41.0.585.gd2178a4bd4-goog


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[PATCH v3 1/8] iommu/arm-smmu-v3: Move ctx_desc out of s1_cfg

[Michael Shavit]

s1_cfg describes the CD table that is inserted into an SMMU's STEs. It's
weird for s1_cfg to also own ctx_desc which describes a CD that is
inserted into that table. It is more appropriate for arm_smmu_domain to
own ctx_desc.

Signed-off-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---

(no changes since v2)

Changes in v2:
- Undo over-reaching column alignment change

 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  2 +-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 23 ++++++++++---------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  6 +++--
 3 files changed, 17 insertions(+), 14 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 a5a63b1c947eb..968559d625c40 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
@@ -62,7 +62,7 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
 		return cd;
 	}
 
-	smmu_domain = container_of(cd, struct arm_smmu_domain, s1_cfg.cd);
+	smmu_domain = container_of(cd, struct arm_smmu_domain, cd);
 	smmu = smmu_domain->smmu;
 
 	ret = xa_alloc(&arm_smmu_asid_xa, &new_asid, cd,
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 9b0dc35056019..bb277ff86f65f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1869,7 +1869,7 @@ static void arm_smmu_tlb_inv_context(void *cookie)
 	 * careful, 007.
 	 */
 	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
-		arm_smmu_tlb_inv_asid(smmu, smmu_domain->s1_cfg.cd.asid);
+		arm_smmu_tlb_inv_asid(smmu, smmu_domain->cd.asid);
 	} else {
 		cmd.opcode	= CMDQ_OP_TLBI_S12_VMALL;
 		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
@@ -1957,7 +1957,7 @@ static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
 	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
 		cmd.opcode	= smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ?
 				  CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA;
-		cmd.tlbi.asid	= smmu_domain->s1_cfg.cd.asid;
+		cmd.tlbi.asid	= smmu_domain->cd.asid;
 	} else {
 		cmd.opcode	= CMDQ_OP_TLBI_S2_IPA;
 		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
@@ -2088,7 +2088,7 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 		mutex_lock(&arm_smmu_asid_lock);
 		if (cfg->cdcfg.cdtab)
 			arm_smmu_free_cd_tables(smmu_domain);
-		arm_smmu_free_asid(&cfg->cd);
+		arm_smmu_free_asid(&smmu_domain->cd);
 		mutex_unlock(&arm_smmu_asid_lock);
 	} else {
 		struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
@@ -2107,13 +2107,14 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	u32 asid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
+	struct arm_smmu_ctx_desc *cd = &smmu_domain->cd;
 	typeof(&pgtbl_cfg->arm_lpae_s1_cfg.tcr) tcr = &pgtbl_cfg->arm_lpae_s1_cfg.tcr;
 
-	refcount_set(&cfg->cd.refs, 1);
+	refcount_set(&cd->refs, 1);
 
 	/* Prevent SVA from modifying the ASID until it is written to the CD */
 	mutex_lock(&arm_smmu_asid_lock);
-	ret = xa_alloc(&arm_smmu_asid_xa, &asid, &cfg->cd,
+	ret = xa_alloc(&arm_smmu_asid_xa, &asid, cd,
 		       XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL);
 	if (ret)
 		goto out_unlock;
@@ -2126,23 +2127,23 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (ret)
 		goto out_free_asid;
 
-	cfg->cd.asid	= (u16)asid;
-	cfg->cd.ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
-	cfg->cd.tcr	= FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, tcr->tsz) |
+	cd->asid	= (u16)asid;
+	cd->ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
+	cd->tcr		= FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, tcr->tsz) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_TG0, tcr->tg) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_IRGN0, tcr->irgn) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_ORGN0, tcr->orgn) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_SH0, tcr->sh) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_IPS, tcr->ips) |
 			  CTXDESC_CD_0_TCR_EPD1 | CTXDESC_CD_0_AA64;
-	cfg->cd.mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair;
+	cd->mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair;
 
 	/*
 	 * Note that this will end up calling arm_smmu_sync_cd() before
 	 * the master has been added to the devices list for this domain.
 	 * This isn't an issue because the STE hasn't been installed yet.
 	 */
-	ret = arm_smmu_write_ctx_desc(smmu_domain, 0, &cfg->cd);
+	ret = arm_smmu_write_ctx_desc(smmu_domain, 0, cd);
 	if (ret)
 		goto out_free_cd_tables;
 
@@ -2152,7 +2153,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 out_free_cd_tables:
 	arm_smmu_free_cd_tables(smmu_domain);
 out_free_asid:
-	arm_smmu_free_asid(&cfg->cd);
+	arm_smmu_free_asid(cd);
 out_unlock:
 	mutex_unlock(&arm_smmu_asid_lock);
 	return ret;
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 dcab85698a4e2..f841383a55a35 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -599,7 +599,6 @@ struct arm_smmu_ctx_desc_cfg {
 
 struct arm_smmu_s1_cfg {
 	struct arm_smmu_ctx_desc_cfg	cdcfg;
-	struct arm_smmu_ctx_desc	cd;
 	u8				s1fmt;
 	u8				s1cdmax;
 };
@@ -724,7 +723,10 @@ struct arm_smmu_domain {
 
 	enum arm_smmu_domain_stage	stage;
 	union {
-		struct arm_smmu_s1_cfg	s1_cfg;
+		struct {
+		struct arm_smmu_ctx_desc	cd;
+		struct arm_smmu_s1_cfg		s1_cfg;
+		};
 		struct arm_smmu_s2_cfg	s2_cfg;
 	};
 
-- 
2.41.0.585.gd2178a4bd4-goog


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[PATCH v3 2/8] iommu/arm-smmu-v3: Replace s1_cfg with cdtab_cfg

[Michael Shavit]

Remove struct arm_smmu_s1_cfg. This is really just a CD table with a
bit of extra information. Enhance the existing CD table structure,
struct arm_smmu_ctx_desc_cfg, with max_cds_bits and replace all usages
of arm_smmu_s1_cfg with arm_smmu_ctx_desc_cfg.

Compute the other values that were stored in s1cfg directly from
existing arm_smmu_ctx_desc_cfg.

For clarity, use the name "cd_table" for the variables pointing to
arm_smmu_ctx_desc_cfg in the new code instead of cdcfg. A later patch
will make this fully consistent.

Signed-off-by: Michael Shavit <mshavit@google.com>
---

Changes in v3:
- Updated commit messages again
- Replace more usages of cdcfg with cdtable (lines that were already
  touched by this commit anyways).

Changes in v2:
- Updated commit message

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 45 +++++++++++----------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 10 ++---
 2 files changed, 26 insertions(+), 29 deletions(-)

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 bb277ff86f65f..ded613aedbb04 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1033,9 +1033,9 @@ static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_domain *smmu_domain,
 	unsigned int idx;
 	struct arm_smmu_l1_ctx_desc *l1_desc;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->s1_cfg.cdcfg;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
 
-	if (smmu_domain->s1_cfg.s1fmt == STRTAB_STE_0_S1FMT_LINEAR)
+	if (!cdcfg->l1_desc)
 		return cdcfg->cdtab + ssid * CTXDESC_CD_DWORDS;
 
 	idx = ssid >> CTXDESC_SPLIT;
@@ -1071,7 +1071,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	bool cd_live;
 	__le64 *cdptr;
 
-	if (WARN_ON(ssid >= (1 << smmu_domain->s1_cfg.s1cdmax)))
+	if (WARN_ON(ssid >= (1 << smmu_domain->cd_table.max_cds_bits)))
 		return -E2BIG;
 
 	cdptr = arm_smmu_get_cd_ptr(smmu_domain, ssid);
@@ -1138,19 +1138,16 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain)
 	size_t l1size;
 	size_t max_contexts;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
-	struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &cfg->cdcfg;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
 
-	max_contexts = 1 << cfg->s1cdmax;
+	max_contexts = 1 << cdcfg->max_cds_bits;
 
 	if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB) ||
 	    max_contexts <= CTXDESC_L2_ENTRIES) {
-		cfg->s1fmt = STRTAB_STE_0_S1FMT_LINEAR;
 		cdcfg->num_l1_ents = max_contexts;
 
 		l1size = max_contexts * (CTXDESC_CD_DWORDS << 3);
 	} else {
-		cfg->s1fmt = STRTAB_STE_0_S1FMT_64K_L2;
 		cdcfg->num_l1_ents = DIV_ROUND_UP(max_contexts,
 						  CTXDESC_L2_ENTRIES);
 
@@ -1186,7 +1183,7 @@ static void arm_smmu_free_cd_tables(struct arm_smmu_domain *smmu_domain)
 	int i;
 	size_t size, l1size;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->s1_cfg.cdcfg;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
 
 	if (cdcfg->l1_desc) {
 		size = CTXDESC_L2_ENTRIES * (CTXDESC_CD_DWORDS << 3);
@@ -1276,7 +1273,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 	u64 val = le64_to_cpu(dst[0]);
 	bool ste_live = false;
 	struct arm_smmu_device *smmu = NULL;
-	struct arm_smmu_s1_cfg *s1_cfg = NULL;
+	struct arm_smmu_ctx_desc_cfg *cd_table = NULL;
 	struct arm_smmu_s2_cfg *s2_cfg = NULL;
 	struct arm_smmu_domain *smmu_domain = NULL;
 	struct arm_smmu_cmdq_ent prefetch_cmd = {
@@ -1294,7 +1291,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 	if (smmu_domain) {
 		switch (smmu_domain->stage) {
 		case ARM_SMMU_DOMAIN_S1:
-			s1_cfg = &smmu_domain->s1_cfg;
+			cd_table = &smmu_domain->cd_table;
 			break;
 		case ARM_SMMU_DOMAIN_S2:
 		case ARM_SMMU_DOMAIN_NESTED:
@@ -1325,7 +1322,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 	val = STRTAB_STE_0_V;
 
 	/* Bypass/fault */
-	if (!smmu_domain || !(s1_cfg || s2_cfg)) {
+	if (!smmu_domain || !(cd_table || s2_cfg)) {
 		if (!smmu_domain && disable_bypass)
 			val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
 		else
@@ -1344,7 +1341,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 		return;
 	}
 
-	if (s1_cfg) {
+	if (cd_table) {
 		u64 strw = smmu->features & ARM_SMMU_FEAT_E2H ?
 			STRTAB_STE_1_STRW_EL2 : STRTAB_STE_1_STRW_NSEL1;
 
@@ -1360,10 +1357,14 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 		    !master->stall_enabled)
 			dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
 
-		val |= (s1_cfg->cdcfg.cdtab_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
-			FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS) |
-			FIELD_PREP(STRTAB_STE_0_S1CDMAX, s1_cfg->s1cdmax) |
-			FIELD_PREP(STRTAB_STE_0_S1FMT, s1_cfg->s1fmt);
+		val |= (cd_table->cdtab_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
+		       FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS) |
+		       FIELD_PREP(STRTAB_STE_0_S1CDMAX,
+				  cd_table->max_cds_bits) |
+		       FIELD_PREP(STRTAB_STE_0_S1FMT,
+				  cd_table->l1_desc ?
+					  STRTAB_STE_0_S1FMT_64K_L2 :
+					  STRTAB_STE_0_S1FMT_LINEAR);
 	}
 
 	if (s2_cfg) {
@@ -2082,11 +2083,11 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 
 	/* Free the CD and ASID, if we allocated them */
 	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
-		struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
+		struct arm_smmu_ctx_desc_cfg *cd_table = &smmu_domain->cd_table;
 
 		/* Prevent SVA from touching the CD while we're freeing it */
 		mutex_lock(&arm_smmu_asid_lock);
-		if (cfg->cdcfg.cdtab)
+		if (cd_table->cdtab)
 			arm_smmu_free_cd_tables(smmu_domain);
 		arm_smmu_free_asid(&smmu_domain->cd);
 		mutex_unlock(&arm_smmu_asid_lock);
@@ -2106,7 +2107,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	int ret;
 	u32 asid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
-	struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
+	struct arm_smmu_ctx_desc_cfg *cd_table = &smmu_domain->cd_table;
 	struct arm_smmu_ctx_desc *cd = &smmu_domain->cd;
 	typeof(&pgtbl_cfg->arm_lpae_s1_cfg.tcr) tcr = &pgtbl_cfg->arm_lpae_s1_cfg.tcr;
 
@@ -2119,7 +2120,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (ret)
 		goto out_unlock;
 
-	cfg->s1cdmax = master->ssid_bits;
+	cd_table->max_cds_bits = master->ssid_bits;
 
 	smmu_domain->stall_enabled = master->stall_enabled;
 
@@ -2457,7 +2458,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		ret = -EINVAL;
 		goto out_unlock;
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
-		   master->ssid_bits != smmu_domain->s1_cfg.s1cdmax) {
+		   master->ssid_bits != smmu_domain->cd_table.max_cds_bits) {
 		ret = -EINVAL;
 		goto out_unlock;
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
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 f841383a55a35..35a93e8858872 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -595,12 +595,8 @@ struct arm_smmu_ctx_desc_cfg {
 	dma_addr_t			cdtab_dma;
 	struct arm_smmu_l1_ctx_desc	*l1_desc;
 	unsigned int			num_l1_ents;
-};
-
-struct arm_smmu_s1_cfg {
-	struct arm_smmu_ctx_desc_cfg	cdcfg;
-	u8				s1fmt;
-	u8				s1cdmax;
+	/* log2 of the maximum number of CDs supported by this table */
+	u8				max_cds_bits;
 };
 
 struct arm_smmu_s2_cfg {
@@ -725,7 +721,7 @@ struct arm_smmu_domain {
 	union {
 		struct {
 		struct arm_smmu_ctx_desc	cd;
-		struct arm_smmu_s1_cfg		s1_cfg;
+		struct arm_smmu_ctx_desc_cfg	cd_table;
 		};
 		struct arm_smmu_s2_cfg	s2_cfg;
 	};
-- 
2.41.0.585.gd2178a4bd4-goog


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[PATCH v3 3/8] iommu/arm-smmu-v3: Encapsulate ctx_desc_cfg init in alloc_cd_tables

[Michael Shavit]

This is slighlty cleaner: arm_smmu_ctx_desc_cfg is initialized in a
single function instead of having pieces set ahead-of time by its caller.

Signed-off-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---

(no changes since v1)

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

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 ded613aedbb04..fe4b19c3b8dee 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1132,7 +1132,8 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	return 0;
 }
 
-static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain)
+static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain,
+				    struct arm_smmu_master *master)
 {
 	int ret;
 	size_t l1size;
@@ -1140,6 +1141,7 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain)
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
 
+	cdcfg->max_cds_bits = master->ssid_bits;
 	max_contexts = 1 << cdcfg->max_cds_bits;
 
 	if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB) ||
@@ -2107,7 +2109,6 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	int ret;
 	u32 asid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
-	struct arm_smmu_ctx_desc_cfg *cd_table = &smmu_domain->cd_table;
 	struct arm_smmu_ctx_desc *cd = &smmu_domain->cd;
 	typeof(&pgtbl_cfg->arm_lpae_s1_cfg.tcr) tcr = &pgtbl_cfg->arm_lpae_s1_cfg.tcr;
 
@@ -2120,11 +2121,9 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (ret)
 		goto out_unlock;
 
-	cd_table->max_cds_bits = master->ssid_bits;
-
 	smmu_domain->stall_enabled = master->stall_enabled;
 
-	ret = arm_smmu_alloc_cd_tables(smmu_domain);
+	ret = arm_smmu_alloc_cd_tables(smmu_domain, master);
 	if (ret)
 		goto out_free_asid;
 
-- 
2.41.0.585.gd2178a4bd4-goog


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[PATCH v3 4/8] iommu/arm-smmu-v3: move stall_enabled to the cd table

[Michael Shavit]

This controls whether CD entries will have the stall bit set when
writing entries into the table.

Signed-off-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---

(no changes since v2)

Changes in v2:
- Use a bitfield instead of a bool for stall_enabled

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 ++++----
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 ++-
 2 files changed, 6 insertions(+), 5 deletions(-)

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 fe4b19c3b8dee..c01023404c26c 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1114,7 +1114,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) |
 			CTXDESC_CD_0_V;
 
-		if (smmu_domain->stall_enabled)
+		if (smmu_domain->cd_table.stall_enabled)
 			val |= CTXDESC_CD_0_S;
 	}
 
@@ -1141,6 +1141,7 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain,
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
 
+	cdcfg->stall_enabled = master->stall_enabled;
 	cdcfg->max_cds_bits = master->ssid_bits;
 	max_contexts = 1 << cdcfg->max_cds_bits;
 
@@ -2121,8 +2122,6 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (ret)
 		goto out_unlock;
 
-	smmu_domain->stall_enabled = master->stall_enabled;
-
 	ret = arm_smmu_alloc_cd_tables(smmu_domain, master);
 	if (ret)
 		goto out_free_asid;
@@ -2461,7 +2460,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		ret = -EINVAL;
 		goto out_unlock;
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
-		   smmu_domain->stall_enabled != master->stall_enabled) {
+		   smmu_domain->cd_table.stall_enabled !=
+			   master->stall_enabled) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}
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 35a93e8858872..05b1f0ee60808 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -597,6 +597,8 @@ struct arm_smmu_ctx_desc_cfg {
 	unsigned int			num_l1_ents;
 	/* log2 of the maximum number of CDs supported by this table */
 	u8				max_cds_bits;
+	/* Whether CD entries in this table have the stall bit set. */
+	u8				stall_enabled:1;
 };
 
 struct arm_smmu_s2_cfg {
@@ -714,7 +716,6 @@ struct arm_smmu_domain {
 	struct mutex			init_mutex; /* Protects smmu pointer */
 
 	struct io_pgtable_ops		*pgtbl_ops;
-	bool				stall_enabled;
 	atomic_t			nr_ats_masters;
 
 	enum arm_smmu_domain_stage	stage;
-- 
2.41.0.585.gd2178a4bd4-goog


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[PATCH v3 5/8] iommu/arm-smmu-v3: Refactor write_ctx_desc

[Michael Shavit]

Update arm_smmu_write_ctx_desc and downstream functions to operate on
a master instead of an smmu domain. We expect arm_smmu_write_ctx_desc()
to only be called to write a CD entry into a CD table owned by the
master. Under the hood, arm_smmu_write_ctx_desc still fetches the CD
table from the domain that is attached to the master, but a subsequent
commit will move that table's ownership to the master.

Note that this change isn't a nop refactor since SVA will call
arm_smmu_write_ctx_desc in a loop for every master the domain is
attached to despite the fact that they all share the same CD table. This
loop may look weird but becomes necessary when the CD table becomes
per-master in a subsequent commit.

Signed-off-by: Michael Shavit <mshavit@google.com>
---

Changes in v3:
- Add a helper to write a CD to all masters that a domain is attached
  to.
- Fixed an issue where an arm_smmu_write_ctx_desc error return wasn't
  correctly handled by its caller.

Changes in v2:
- minor style fixes

Changes in v1:
- arm_smmu_write_ctx_desc now get's the CD table to write to from the
  master parameter instead of a distinct parameter. This works well
  because the CD table being written to should always be owned by the
  master by the end of this series. This version no longer allows master
  to be NULL.

 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 31 +++++++++--
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 51 +++++++------------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  2 +-
 3 files changed, 46 insertions(+), 38 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 968559d625c40..e3992a0c16377 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
@@ -37,6 +37,24 @@ struct arm_smmu_bond {
 
 static DEFINE_MUTEX(sva_lock);
 
+static int arm_smmu_write_ctx_desc_devices(struct arm_smmu_domain *smmu_domain,
+					    int ssid,
+					    struct arm_smmu_ctx_desc *cd)
+{
+	struct arm_smmu_master *master;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
+	list_for_each_entry(master, &smmu_domain->devices, domain_head) {
+		ret = arm_smmu_write_ctx_desc(master, ssid, cd);
+		if (ret)
+			break;
+	}
+	spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
+	return ret;
+}
+
 /*
  * Check if the CPU ASID is available on the SMMU side. If a private context
  * descriptor is using it, try to replace it.
@@ -80,7 +98,7 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
 	 * be some overlap between use of both ASIDs, until we invalidate the
 	 * TLB.
 	 */
-	arm_smmu_write_ctx_desc(smmu_domain, 0, cd);
+	arm_smmu_write_ctx_desc_devices(smmu_domain, 0, cd);
 
 	/* Invalidate TLB entries previously associated with that context */
 	arm_smmu_tlb_inv_asid(smmu, asid);
@@ -222,7 +240,7 @@ static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 	 * DMA may still be running. Keep the cd valid to avoid C_BAD_CD events,
 	 * but disable translation.
 	 */
-	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
+	arm_smmu_write_ctx_desc_devices(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);
@@ -279,9 +297,11 @@ arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain,
 		goto err_free_cd;
 	}
 
-	ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd);
-	if (ret)
+	ret = arm_smmu_write_ctx_desc_devices(smmu_domain, mm->pasid, cd);
+	if (ret) {
+		arm_smmu_write_ctx_desc_devices(smmu_domain, mm->pasid, NULL);
 		goto err_put_notifier;
+	}
 
 	list_add(&smmu_mn->list, &smmu_domain->mmu_notifiers);
 	return smmu_mn;
@@ -304,7 +324,8 @@ static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
 		return;
 
 	list_del(&smmu_mn->list);
-	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL);
+
+	arm_smmu_write_ctx_desc_devices(smmu_domain, mm->pasid, NULL);
 
 	/*
 	 * If we went through clear(), we've already invalidated, and no
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 c01023404c26c..34bd7815aeb8e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -971,14 +971,12 @@ void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid)
 	arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 }
 
-static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain,
+static void arm_smmu_sync_cd(struct arm_smmu_master *master,
 			     int ssid, bool leaf)
 {
 	size_t i;
-	unsigned long flags;
-	struct arm_smmu_master *master;
 	struct arm_smmu_cmdq_batch cmds;
-	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	struct arm_smmu_device *smmu = master->smmu;
 	struct arm_smmu_cmdq_ent cmd = {
 		.opcode	= CMDQ_OP_CFGI_CD,
 		.cfgi	= {
@@ -988,15 +986,10 @@ static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain,
 	};
 
 	cmds.num = 0;
-
-	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
-	list_for_each_entry(master, &smmu_domain->devices, domain_head) {
-		for (i = 0; i < master->num_streams; i++) {
-			cmd.cfgi.sid = master->streams[i].id;
-			arm_smmu_cmdq_batch_add(smmu, &cmds, &cmd);
-		}
+	for (i = 0; i < master->num_streams; i++) {
+		cmd.cfgi.sid = master->streams[i].id;
+		arm_smmu_cmdq_batch_add(smmu, &cmds, &cmd);
 	}
-	spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
 
 	arm_smmu_cmdq_batch_submit(smmu, &cmds);
 }
@@ -1026,14 +1019,13 @@ static void arm_smmu_write_cd_l1_desc(__le64 *dst,
 	WRITE_ONCE(*dst, cpu_to_le64(val));
 }
 
-static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_domain *smmu_domain,
-				   u32 ssid)
+static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_master *master, u32 ssid)
 {
 	__le64 *l1ptr;
 	unsigned int idx;
 	struct arm_smmu_l1_ctx_desc *l1_desc;
-	struct arm_smmu_device *smmu = smmu_domain->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
+	struct arm_smmu_device *smmu = master->smmu;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->domain->cd_table;
 
 	if (!cdcfg->l1_desc)
 		return cdcfg->cdtab + ssid * CTXDESC_CD_DWORDS;
@@ -1047,13 +1039,13 @@ static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_domain *smmu_domain,
 		l1ptr = cdcfg->cdtab + idx * CTXDESC_L1_DESC_DWORDS;
 		arm_smmu_write_cd_l1_desc(l1ptr, l1_desc);
 		/* An invalid L1CD can be cached */
-		arm_smmu_sync_cd(smmu_domain, ssid, false);
+		arm_smmu_sync_cd(master, ssid, false);
 	}
 	idx = ssid & (CTXDESC_L2_ENTRIES - 1);
 	return l1_desc->l2ptr + idx * CTXDESC_CD_DWORDS;
 }
 
-int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
+int arm_smmu_write_ctx_desc(struct arm_smmu_master *master, int ssid,
 			    struct arm_smmu_ctx_desc *cd)
 {
 	/*
@@ -1070,11 +1062,12 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	u64 val;
 	bool cd_live;
 	__le64 *cdptr;
+	struct arm_smmu_ctx_desc_cfg *cd_table = &master->domain->cd_table;
 
-	if (WARN_ON(ssid >= (1 << smmu_domain->cd_table.max_cds_bits)))
+	if (WARN_ON(ssid >= (1 << cd_table->max_cds_bits)))
 		return -E2BIG;
 
-	cdptr = arm_smmu_get_cd_ptr(smmu_domain, ssid);
+	cdptr = arm_smmu_get_cd_ptr(master, ssid);
 	if (!cdptr)
 		return -ENOMEM;
 
@@ -1102,7 +1095,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 		 * order. Ensure that it observes valid values before reading
 		 * V=1.
 		 */
-		arm_smmu_sync_cd(smmu_domain, ssid, true);
+		arm_smmu_sync_cd(master, ssid, true);
 
 		val = cd->tcr |
 #ifdef __BIG_ENDIAN
@@ -1114,7 +1107,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) |
 			CTXDESC_CD_0_V;
 
-		if (smmu_domain->cd_table.stall_enabled)
+		if (cd_table->stall_enabled)
 			val |= CTXDESC_CD_0_S;
 	}
 
@@ -1128,7 +1121,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	 *   without first making the structure invalid.
 	 */
 	WRITE_ONCE(cdptr[0], cpu_to_le64(val));
-	arm_smmu_sync_cd(smmu_domain, ssid, true);
+	arm_smmu_sync_cd(master, ssid, true);
 	return 0;
 }
 
@@ -1138,7 +1131,7 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain,
 	int ret;
 	size_t l1size;
 	size_t max_contexts;
-	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	struct arm_smmu_device *smmu = master->smmu;
 	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
 
 	cdcfg->stall_enabled = master->stall_enabled;
@@ -2137,12 +2130,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 			  CTXDESC_CD_0_TCR_EPD1 | CTXDESC_CD_0_AA64;
 	cd->mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair;
 
-	/*
-	 * Note that this will end up calling arm_smmu_sync_cd() before
-	 * the master has been added to the devices list for this domain.
-	 * This isn't an issue because the STE hasn't been installed yet.
-	 */
-	ret = arm_smmu_write_ctx_desc(smmu_domain, 0, cd);
+	ret = arm_smmu_write_ctx_desc(master, 0, cd);
 	if (ret)
 		goto out_free_cd_tables;
 
@@ -2460,8 +2448,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		ret = -EINVAL;
 		goto out_unlock;
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
-		   smmu_domain->cd_table.stall_enabled !=
-			   master->stall_enabled) {
+		   smmu_domain->cd_table.stall_enabled != master->stall_enabled) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}
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 05b1f0ee60808..6066a09c01996 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -744,7 +744,7 @@ extern struct xarray arm_smmu_asid_xa;
 extern struct mutex arm_smmu_asid_lock;
 extern struct arm_smmu_ctx_desc quiet_cd;
 
-int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
+int arm_smmu_write_ctx_desc(struct arm_smmu_master *smmu_master, int ssid,
 			    struct arm_smmu_ctx_desc *cd);
 void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
 void arm_smmu_tlb_inv_range_asid(unsigned long iova, size_t size, int asid,
-- 
2.41.0.585.gd2178a4bd4-goog


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[PATCH v3 6/8] iommu/arm-smmu-v3: Move CD table to arm_smmu_master

[Michael Shavit]

With this change, each master will now own its own CD table instead of
sharing one with other masters attached to the same domain. Attaching a
stage 1 domain installs CD entries into the master's CD table. SVA
writes its CD entries into each master's CD table if the domain is
shared across masters.

Signed-off-by: Michael Shavit <mshavit@google.com>
---

(no changes since v2)

Changes in v2:
- Allocate CD table when it's first needed instead of on probe.

Changes in v1:
- The master's CD table allocation was previously split to a different
  commit. This change now atomically allocates the new CD table, uses
  it, and removes the old one.

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 65 +++++++++------------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  6 +-
 2 files changed, 31 insertions(+), 40 deletions(-)

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 34bd7815aeb8e..b05963cd4e5b5 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1025,7 +1025,7 @@ static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_master *master, u32 ssid)
 	unsigned int idx;
 	struct arm_smmu_l1_ctx_desc *l1_desc;
 	struct arm_smmu_device *smmu = master->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->domain->cd_table;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->cd_table;
 
 	if (!cdcfg->l1_desc)
 		return cdcfg->cdtab + ssid * CTXDESC_CD_DWORDS;
@@ -1062,7 +1062,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_master *master, int ssid,
 	u64 val;
 	bool cd_live;
 	__le64 *cdptr;
-	struct arm_smmu_ctx_desc_cfg *cd_table = &master->domain->cd_table;
+	struct arm_smmu_ctx_desc_cfg *cd_table = &master->cd_table;
 
 	if (WARN_ON(ssid >= (1 << cd_table->max_cds_bits)))
 		return -E2BIG;
@@ -1125,14 +1125,13 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_master *master, int ssid,
 	return 0;
 }
 
-static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain,
-				    struct arm_smmu_master *master)
+static int arm_smmu_alloc_cd_tables(struct arm_smmu_master *master)
 {
 	int ret;
 	size_t l1size;
 	size_t max_contexts;
 	struct arm_smmu_device *smmu = master->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->cd_table;
 
 	cdcfg->stall_enabled = master->stall_enabled;
 	cdcfg->max_cds_bits = master->ssid_bits;
@@ -1174,12 +1173,12 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain,
 	return ret;
 }
 
-static void arm_smmu_free_cd_tables(struct arm_smmu_domain *smmu_domain)
+static void arm_smmu_free_cd_tables(struct arm_smmu_master *master)
 {
 	int i;
 	size_t size, l1size;
-	struct arm_smmu_device *smmu = smmu_domain->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
+	struct arm_smmu_device *smmu = master->smmu;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->cd_table;
 
 	if (cdcfg->l1_desc) {
 		size = CTXDESC_L2_ENTRIES * (CTXDESC_CD_DWORDS << 3);
@@ -1287,7 +1286,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 	if (smmu_domain) {
 		switch (smmu_domain->stage) {
 		case ARM_SMMU_DOMAIN_S1:
-			cd_table = &smmu_domain->cd_table;
+			cd_table = &master->cd_table;
 			break;
 		case ARM_SMMU_DOMAIN_S2:
 		case ARM_SMMU_DOMAIN_NESTED:
@@ -2077,14 +2076,10 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 
 	free_io_pgtable_ops(smmu_domain->pgtbl_ops);
 
-	/* Free the CD and ASID, if we allocated them */
+	/* Free the ASID or VMID */
 	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
-		struct arm_smmu_ctx_desc_cfg *cd_table = &smmu_domain->cd_table;
-
 		/* Prevent SVA from touching the CD while we're freeing it */
 		mutex_lock(&arm_smmu_asid_lock);
-		if (cd_table->cdtab)
-			arm_smmu_free_cd_tables(smmu_domain);
 		arm_smmu_free_asid(&smmu_domain->cd);
 		mutex_unlock(&arm_smmu_asid_lock);
 	} else {
@@ -2096,7 +2091,7 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 	kfree(smmu_domain);
 }
 
-static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
+static int arm_smmu_domain_finalise_cd(struct arm_smmu_domain *smmu_domain,
 				       struct arm_smmu_master *master,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
@@ -2115,10 +2110,6 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (ret)
 		goto out_unlock;
 
-	ret = arm_smmu_alloc_cd_tables(smmu_domain, master);
-	if (ret)
-		goto out_free_asid;
-
 	cd->asid	= (u16)asid;
 	cd->ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
 	cd->tcr		= FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, tcr->tsz) |
@@ -2130,17 +2121,9 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 			  CTXDESC_CD_0_TCR_EPD1 | CTXDESC_CD_0_AA64;
 	cd->mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair;
 
-	ret = arm_smmu_write_ctx_desc(master, 0, cd);
-	if (ret)
-		goto out_free_cd_tables;
-
 	mutex_unlock(&arm_smmu_asid_lock);
 	return 0;
 
-out_free_cd_tables:
-	arm_smmu_free_cd_tables(smmu_domain);
-out_free_asid:
-	arm_smmu_free_asid(cd);
 out_unlock:
 	mutex_unlock(&arm_smmu_asid_lock);
 	return ret;
@@ -2203,7 +2186,7 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain,
 		ias = min_t(unsigned long, ias, VA_BITS);
 		oas = smmu->ias;
 		fmt = ARM_64_LPAE_S1;
-		finalise_stage_fn = arm_smmu_domain_finalise_s1;
+		finalise_stage_fn = arm_smmu_domain_finalise_cd;
 		break;
 	case ARM_SMMU_DOMAIN_NESTED:
 	case ARM_SMMU_DOMAIN_S2:
@@ -2443,14 +2426,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	} else if (smmu_domain->smmu != smmu) {
 		ret = -EINVAL;
 		goto out_unlock;
-	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
-		   master->ssid_bits != smmu_domain->cd_table.max_cds_bits) {
-		ret = -EINVAL;
-		goto out_unlock;
-	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
-		   smmu_domain->cd_table.stall_enabled != master->stall_enabled) {
-		ret = -EINVAL;
-		goto out_unlock;
 	}
 
 	master->domain = smmu_domain;
@@ -2465,6 +2440,22 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
 		master->ats_enabled = arm_smmu_ats_supported(master);
 
+	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
+		if (!master->cd_table.cdtab) {
+			ret = arm_smmu_alloc_cd_tables(master);
+			if (ret) {
+				master->domain = NULL;
+				goto out_unlock;
+			}
+		}
+
+		ret = arm_smmu_write_ctx_desc(master, 0, &smmu_domain->cd);
+		if (ret) {
+			master->domain = NULL;
+			goto out_unlock;
+		}
+	}
+
 	arm_smmu_install_ste_for_dev(master);
 
 	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
@@ -2719,6 +2710,8 @@ static void arm_smmu_release_device(struct device *dev)
 	arm_smmu_detach_dev(master);
 	arm_smmu_disable_pasid(master);
 	arm_smmu_remove_master(master);
+	if (master->cd_table.cdtab_dma)
+		arm_smmu_free_cd_tables(master);
 	kfree(master);
 }
 
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 6066a09c01996..f2acfcc1af925 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -694,6 +694,7 @@ struct arm_smmu_master {
 	struct arm_smmu_domain		*domain;
 	struct list_head		domain_head;
 	struct arm_smmu_stream		*streams;
+	struct arm_smmu_ctx_desc_cfg	cd_table;
 	unsigned int			num_streams;
 	bool				ats_enabled;
 	bool				stall_enabled;
@@ -720,11 +721,8 @@ struct arm_smmu_domain {
 
 	enum arm_smmu_domain_stage	stage;
 	union {
-		struct {
 		struct arm_smmu_ctx_desc	cd;
-		struct arm_smmu_ctx_desc_cfg	cd_table;
-		};
-		struct arm_smmu_s2_cfg	s2_cfg;
+		struct arm_smmu_s2_cfg		s2_cfg;
 	};
 
 	struct iommu_domain		domain;
-- 
2.41.0.585.gd2178a4bd4-goog


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[PATCH v3 7/8] iommu/arm-smmu-v3: Skip cd sync if CD table isn't active

[Michael Shavit]

This commit explicitly keeps track of whether a CD table is installed in
an STE so that arm_smmu_sync_cd can skip the sync when unnecessary. This
was previously achieved through the domain->devices list, but we are
moving to a model where arm_smmu_sync_cd directly operates on a master
and the master's CD table instead of a domain.

Signed-off-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---

Changes in v3:
- Flip the cd_table.installed bit back off when table is detached
- re-order the commit later in the series since flipping the installed
  bit to off isn't obvious when the cd_table is still shared by multiple
  masters.

Changes in v2:
- Store field as a bit instead of a bool. Fix comment about STE being
  live before the sync in write_ctx_desc().

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 +++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 ++
 2 files changed, 9 insertions(+), 1 deletion(-)

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 b05963cd4e5b5..94922d4ff7be0 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -985,6 +985,9 @@ static void arm_smmu_sync_cd(struct arm_smmu_master *master,
 		},
 	};
 
+	if (!master->cd_table.installed)
+		return;
+
 	cmds.num = 0;
 	for (i = 0; i < master->num_streams; i++) {
 		cmd.cfgi.sid = master->streams[i].id;
@@ -1091,7 +1094,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_master *master, int ssid,
 		cdptr[3] = cpu_to_le64(cd->mair);
 
 		/*
-		 * STE is live, and the SMMU might read dwords of this CD in any
+		 * STE may be live, and the SMMU might read dwords of this CD in any
 		 * order. Ensure that it observes valid values before reading
 		 * V=1.
 		 */
@@ -1360,6 +1363,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 				  cd_table->l1_desc ?
 					  STRTAB_STE_0_S1FMT_64K_L2 :
 					  STRTAB_STE_0_S1FMT_LINEAR);
+		cd_table->installed = true;
+	} else {
+		master->cd_table.installed = false;
 	}
 
 	if (s2_cfg) {
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 f2acfcc1af925..0ee3dc7291a15 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -599,6 +599,8 @@ struct arm_smmu_ctx_desc_cfg {
 	u8				max_cds_bits;
 	/* Whether CD entries in this table have the stall bit set. */
 	u8				stall_enabled:1;
+	/* Whether this CD table is installed in any STE */
+	u8				installed:1;
 };
 
 struct arm_smmu_s2_cfg {
-- 
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[PATCH v3 8/8] iommu/arm-smmu-v3: Rename cdcfg to cd_table

[Michael Shavit]

cdcfg is a confusing name, especially given other variables with the cfg
suffix in this driver. cd_table more clearly describes what is being
operated on.

Signed-off-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---

Changes in v3:
- Commit message update

Changes in v2:
- New commit

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 66 ++++++++++-----------
 1 file changed, 33 insertions(+), 33 deletions(-)

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 94922d4ff7be0..fc57155efb6b9 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1028,18 +1028,18 @@ static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_master *master, u32 ssid)
 	unsigned int idx;
 	struct arm_smmu_l1_ctx_desc *l1_desc;
 	struct arm_smmu_device *smmu = master->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->cd_table;
+	struct arm_smmu_ctx_desc_cfg *cd_table = &master->cd_table;
 
-	if (!cdcfg->l1_desc)
-		return cdcfg->cdtab + ssid * CTXDESC_CD_DWORDS;
+	if (!cd_table->l1_desc)
+		return cd_table->cdtab + ssid * CTXDESC_CD_DWORDS;
 
 	idx = ssid >> CTXDESC_SPLIT;
-	l1_desc = &cdcfg->l1_desc[idx];
+	l1_desc = &cd_table->l1_desc[idx];
 	if (!l1_desc->l2ptr) {
 		if (arm_smmu_alloc_cd_leaf_table(smmu, l1_desc))
 			return NULL;
 
-		l1ptr = cdcfg->cdtab + idx * CTXDESC_L1_DESC_DWORDS;
+		l1ptr = cd_table->cdtab + idx * CTXDESC_L1_DESC_DWORDS;
 		arm_smmu_write_cd_l1_desc(l1ptr, l1_desc);
 		/* An invalid L1CD can be cached */
 		arm_smmu_sync_cd(master, ssid, false);
@@ -1134,33 +1134,33 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_master *master)
 	size_t l1size;
 	size_t max_contexts;
 	struct arm_smmu_device *smmu = master->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->cd_table;
+	struct arm_smmu_ctx_desc_cfg *cd_table = &master->cd_table;
 
-	cdcfg->stall_enabled = master->stall_enabled;
-	cdcfg->max_cds_bits = master->ssid_bits;
-	max_contexts = 1 << cdcfg->max_cds_bits;
+	cd_table->stall_enabled = master->stall_enabled;
+	cd_table->max_cds_bits = master->ssid_bits;
+	max_contexts = 1 << cd_table->max_cds_bits;
 
 	if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB) ||
 	    max_contexts <= CTXDESC_L2_ENTRIES) {
-		cdcfg->num_l1_ents = max_contexts;
+		cd_table->num_l1_ents = max_contexts;
 
 		l1size = max_contexts * (CTXDESC_CD_DWORDS << 3);
 	} else {
-		cdcfg->num_l1_ents = DIV_ROUND_UP(max_contexts,
+		cd_table->num_l1_ents = DIV_ROUND_UP(max_contexts,
 						  CTXDESC_L2_ENTRIES);
 
-		cdcfg->l1_desc = devm_kcalloc(smmu->dev, cdcfg->num_l1_ents,
-					      sizeof(*cdcfg->l1_desc),
+		cd_table->l1_desc = devm_kcalloc(smmu->dev, cd_table->num_l1_ents,
+					      sizeof(*cd_table->l1_desc),
 					      GFP_KERNEL);
-		if (!cdcfg->l1_desc)
+		if (!cd_table->l1_desc)
 			return -ENOMEM;
 
-		l1size = cdcfg->num_l1_ents * (CTXDESC_L1_DESC_DWORDS << 3);
+		l1size = cd_table->num_l1_ents * (CTXDESC_L1_DESC_DWORDS << 3);
 	}
 
-	cdcfg->cdtab = dmam_alloc_coherent(smmu->dev, l1size, &cdcfg->cdtab_dma,
+	cd_table->cdtab = dmam_alloc_coherent(smmu->dev, l1size, &cd_table->cdtab_dma,
 					   GFP_KERNEL);
-	if (!cdcfg->cdtab) {
+	if (!cd_table->cdtab) {
 		dev_warn(smmu->dev, "failed to allocate context descriptor\n");
 		ret = -ENOMEM;
 		goto err_free_l1;
@@ -1169,9 +1169,9 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_master *master)
 	return 0;
 
 err_free_l1:
-	if (cdcfg->l1_desc) {
-		devm_kfree(smmu->dev, cdcfg->l1_desc);
-		cdcfg->l1_desc = NULL;
+	if (cd_table->l1_desc) {
+		devm_kfree(smmu->dev, cd_table->l1_desc);
+		cd_table->l1_desc = NULL;
 	}
 	return ret;
 }
@@ -1181,30 +1181,30 @@ static void arm_smmu_free_cd_tables(struct arm_smmu_master *master)
 	int i;
 	size_t size, l1size;
 	struct arm_smmu_device *smmu = master->smmu;
-	struct arm_smmu_ctx_desc_cfg *cdcfg = &master->cd_table;
+	struct arm_smmu_ctx_desc_cfg *cd_table = &master->cd_table;
 
-	if (cdcfg->l1_desc) {
+	if (cd_table->l1_desc) {
 		size = CTXDESC_L2_ENTRIES * (CTXDESC_CD_DWORDS << 3);
 
-		for (i = 0; i < cdcfg->num_l1_ents; i++) {
-			if (!cdcfg->l1_desc[i].l2ptr)
+		for (i = 0; i < cd_table->num_l1_ents; i++) {
+			if (!cd_table->l1_desc[i].l2ptr)
 				continue;
 
 			dmam_free_coherent(smmu->dev, size,
-					   cdcfg->l1_desc[i].l2ptr,
-					   cdcfg->l1_desc[i].l2ptr_dma);
+					   cd_table->l1_desc[i].l2ptr,
+					   cd_table->l1_desc[i].l2ptr_dma);
 		}
-		devm_kfree(smmu->dev, cdcfg->l1_desc);
-		cdcfg->l1_desc = NULL;
+		devm_kfree(smmu->dev, cd_table->l1_desc);
+		cd_table->l1_desc = NULL;
 
-		l1size = cdcfg->num_l1_ents * (CTXDESC_L1_DESC_DWORDS << 3);
+		l1size = cd_table->num_l1_ents * (CTXDESC_L1_DESC_DWORDS << 3);
 	} else {
-		l1size = cdcfg->num_l1_ents * (CTXDESC_CD_DWORDS << 3);
+		l1size = cd_table->num_l1_ents * (CTXDESC_CD_DWORDS << 3);
 	}
 
-	dmam_free_coherent(smmu->dev, l1size, cdcfg->cdtab, cdcfg->cdtab_dma);
-	cdcfg->cdtab_dma = 0;
-	cdcfg->cdtab = NULL;
+	dmam_free_coherent(smmu->dev, l1size, cd_table->cdtab, cd_table->cdtab_dma);
+	cd_table->cdtab_dma = 0;
+	cd_table->cdtab = NULL;
 }
 
 bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd)
-- 
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Re: [PATCH v3 2/8] iommu/arm-smmu-v3: Replace s1_cfg with cdtab_cfg

[Jason Gunthorpe]

On Wed, Aug 02, 2023 at 02:35:19AM +0800, Michael Shavit wrote:
> Remove struct arm_smmu_s1_cfg. This is really just a CD table with a
> bit of extra information. Enhance the existing CD table structure,
> struct arm_smmu_ctx_desc_cfg, with max_cds_bits and replace all usages
> of arm_smmu_s1_cfg with arm_smmu_ctx_desc_cfg.
> 
> Compute the other values that were stored in s1cfg directly from
> existing arm_smmu_ctx_desc_cfg.
> 
> For clarity, use the name "cd_table" for the variables pointing to
> arm_smmu_ctx_desc_cfg in the new code instead of cdcfg. A later patch
> will make this fully consistent.
> 
> Signed-off-by: Michael Shavit <mshavit@google.com>
> ---
> 
> Changes in v3:
> - Updated commit messages again
> - Replace more usages of cdcfg with cdtable (lines that were already
>   touched by this commit anyways).
> 
> Changes in v2:
> - Updated commit message
> 
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 45 +++++++++++----------
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 10 ++---
>  2 files changed, 26 insertions(+), 29 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

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Re: [PATCH v3 5/8] iommu/arm-smmu-v3: Refactor write_ctx_desc

[Jason Gunthorpe]

On Wed, Aug 02, 2023 at 02:35:22AM +0800, Michael Shavit wrote:
> Update arm_smmu_write_ctx_desc and downstream functions to operate on
> a master instead of an smmu domain. We expect arm_smmu_write_ctx_desc()
> to only be called to write a CD entry into a CD table owned by the
> master. Under the hood, arm_smmu_write_ctx_desc still fetches the CD
> table from the domain that is attached to the master, but a subsequent
> commit will move that table's ownership to the master.
> 
> Note that this change isn't a nop refactor since SVA will call
> arm_smmu_write_ctx_desc in a loop for every master the domain is
> attached to despite the fact that they all share the same CD table. This
> loop may look weird but becomes necessary when the CD table becomes
> per-master in a subsequent commit.
> 
> Signed-off-by: Michael Shavit <mshavit@google.com>
> ---
> 
> Changes in v3:
> - Add a helper to write a CD to all masters that a domain is attached
>   to.
> - Fixed an issue where an arm_smmu_write_ctx_desc error return wasn't
>   correctly handled by its caller.
> 
> Changes in v2:
> - minor style fixes
> 
> Changes in v1:
> - arm_smmu_write_ctx_desc now get's the CD table to write to from the
>   master parameter instead of a distinct parameter. This works well
>   because the CD table being written to should always be owned by the
>   master by the end of this series. This version no longer allows master
>   to be NULL.
> 
>  .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 31 +++++++++--
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 51 +++++++------------
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  2 +-
>  3 files changed, 46 insertions(+), 38 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

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Re: [PATCH v3 6/8] iommu/arm-smmu-v3: Move CD table to arm_smmu_master

[Jason Gunthorpe]

On Wed, Aug 02, 2023 at 02:35:23AM +0800, Michael Shavit wrote:
> @@ -2465,6 +2440,22 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>  	if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
>  		master->ats_enabled = arm_smmu_ats_supported(master);
>  
> +	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> +		if (!master->cd_table.cdtab) {
> +			ret = arm_smmu_alloc_cd_tables(master);
> +			if (ret) {

Again, I didn't look very closely at your locking, but what lock is
being held to protect the read of master->cd_table.cdtab ?

> +				master->domain = NULL;
> +				goto out_unlock;

This is only the domain lock:
	mutex_unlock(&smmu_domain->init_mutex);

Which is no longer sufficient.

You need some kind of lock in the master struct to protect the shared
cd table and everything in it?

Jason

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Re: [PATCH v3 6/8] iommu/arm-smmu-v3: Move CD table to arm_smmu_master

[Michael Shavit]

On Wed, Aug 2, 2023 at 7:53 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> On Wed, Aug 02, 2023 at 02:35:23AM +0800, Michael Shavit wrote:
> > @@ -2465,6 +2440,22 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
> >       if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
> >               master->ats_enabled = arm_smmu_ats_supported(master);
> >
> > +     if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> > +             if (!master->cd_table.cdtab) {
> > +                     ret = arm_smmu_alloc_cd_tables(master);
> > +                     if (ret) {
>
> Again, I didn't look very closely at your locking, but what lock is
> being held to protect the read of master->cd_table.cdtab ?

The cd_table is only written into (with write_ctx_desc) when something
attaches or detaches (SVA is a little weird, but it handles locking
internally, and blocks all non-sva attach/detach calls while enabled).
The cd_table itself is allocated on first attach, and freed on release.

Doesn't the iommu framework guarantee that attach_dev (and
release_device) won't have concurrent calls for a given master through
the group lock? I can add an internal lock if relying on the iommu
lock is not OK.

> > +                             master->domain = NULL;
> > +                             goto out_unlock;
>
> This is only the domain lock:
>         mutex_unlock(&smmu_domain->init_mutex);
>
> Which is no longer sufficient.

Hmmm yeah that lock looks misleading here. Let me move the unlock
further up so that it more clearly surrounds the section it protects.

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Re: [PATCH v3 6/8] iommu/arm-smmu-v3: Move CD table to arm_smmu_master

[Jason Gunthorpe]

On Wed, Aug 02, 2023 at 07:19:12PM +0800, Michael Shavit wrote:
> On Wed, Aug 2, 2023 at 7:53 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
> >
> > On Wed, Aug 02, 2023 at 02:35:23AM +0800, Michael Shavit wrote:
> > > @@ -2465,6 +2440,22 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
> > >       if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
> > >               master->ats_enabled = arm_smmu_ats_supported(master);
> > >
> > > +     if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> > > +             if (!master->cd_table.cdtab) {
> > > +                     ret = arm_smmu_alloc_cd_tables(master);
> > > +                     if (ret) {
> >
> > Again, I didn't look very closely at your locking, but what lock is
> > being held to protect the read of master->cd_table.cdtab ?
> 
> The cd_table is only written into (with write_ctx_desc) when something
> attaches or detaches (SVA is a little weird, but it handles locking
> internally, and blocks all non-sva attach/detach calls while enabled).
> The cd_table itself is allocated on first attach, and freed on release.
> 
> Doesn't the iommu framework guarantee that attach_dev (and
> release_device) won't have concurrent calls for a given master through
> the group lock? I can add an internal lock if relying on the iommu
> lock is not OK.

Yes that is right.

So, a comment about that in the struct around those variables would be
helpful (locked by the iommu core using the group mutex)

But the code is fine

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

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