[PATCH v7 4/9] iommu/arm-smmu-v3: move stall_enabled to the cd table

From: Michael Shavit
Date: Thu Aug 31 2023 - 13:46:13 EST


A domain can be attached to multiple masters with different
master->stall_enabled values. The stall bit of a CD entry should follow
master->stall_enabled and has an inverse relationship with the
STE.S1STALLD bit.

The stall_enabled bit does not depend on any property of the domain, so
move it out of the arm_smmu_domain struct. Move it to the CD table
struct so that it can fully describe how CD entries should be written to
it.

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Michael Shavit <mshavit@xxxxxxxxxx>
---

(no changes since v5)

Changes in v5:
- Reword commit

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 5bb13fadb41ad..44df7c0926802 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->s1cdmax = master->ssid_bits;
max_contexts = 1 << cdcfg->s1cdmax;

@@ -2119,8 +2120,6 @@ 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;
@@ -2459,7 +2458,8 @@ 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 5f0e7468db5f3..007758df57610 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -598,6 +598,8 @@ struct arm_smmu_ctx_desc_cfg {
u8 s1fmt;
/* log2 of the maximum number of CDs supported by this table */
u8 s1cdmax;
+ /* Whether CD entries in this table have the stall bit set. */
+ u8 stall_enabled:1;
};

struct arm_smmu_s2_cfg {
@@ -715,7 +717,6 @@ 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;
--
2.42.0.283.g2d96d420d3-goog