[PATCH v7 4/9] iommu/arm-smmu-v3: Consolidate clearing a CD table entry

Jason Gunthorpe
2024-04-16T19:29:19Z

A cleared entry is all 0's. Make arm_smmu_clear_cd() do this sequence.

If we are clearing an entry and for some reason it is not already
allocated in the CD table then something has gone wrong.

Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Moritz Fischer <moritzf@google.com>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 2 +-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 20 ++++++++++++++-----
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 +
3 files changed, 17 insertions(+), 6 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 d159f60480935e..7cf286f7a009fb 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
@@ -569,7 +569,7 @@ void arm_smmu_sva_remove_dev_pasid(struct iommu_domain *domain,

mutex_lock(&sva_lock);

- arm_smmu_write_ctx_desc(master, id, NULL);
+ arm_smmu_clear_cd(master, id);

list_for_each_entry(t, &master->bonds, list) {
if (t->mm == mm) {
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 d24fa13a52b4e0..f3df1ec8d258dc 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1309,6 +1309,19 @@ void arm_smmu_make_s1_cd(struct arm_smmu_cd *target,
target->data[3] = cpu_to_le64(cd->mair);
}

+void arm_smmu_clear_cd(struct arm_smmu_master *master, ioasid_t ssid)
+{
+ struct arm_smmu_cd target = {};
+ struct arm_smmu_cd *cdptr;
+
+ if (!master->cd_table.cdtab)
+ return;
+ cdptr = arm_smmu_get_cd_ptr(master, ssid);
+ if (WARN_ON(!cdptr))
+ return;
+ arm_smmu_write_cd_entry(master, ssid, cdptr, &target);
+}
+
static void arm_smmu_clean_cd_entry(struct arm_smmu_cd *target)
{
struct arm_smmu_cd used = {};
@@ -2696,9 +2709,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
case ARM_SMMU_DOMAIN_S2:
arm_smmu_make_s2_domain_ste(&target, master, smmu_domain);
arm_smmu_install_ste_for_dev(master, &target);
- if (master->cd_table.cdtab)
- arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID,
- NULL);
+ arm_smmu_clear_cd(master, IOMMU_NO_PASID);
break;
}

@@ -2746,8 +2757,7 @@ static int arm_smmu_attach_dev_ste(struct device *dev,
* arm_smmu_domain->devices to avoid races updating the same context
* descriptor from arm_smmu_share_asid().
*/
- if (master->cd_table.cdtab)
- arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID, NULL);
+ arm_smmu_clear_cd(master, IOMMU_NO_PASID);
return 0;
}

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 bb08f087ba39e4..99fd6f24caa818 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -751,6 +751,7 @@ extern struct xarray arm_smmu_asid_xa;
extern struct mutex arm_smmu_asid_lock;
extern struct arm_smmu_ctx_desc quiet_cd;

+void arm_smmu_clear_cd(struct arm_smmu_master *master, ioasid_t ssid);
struct arm_smmu_cd *arm_smmu_get_cd_ptr(struct arm_smmu_master *master,
u32 ssid);
void arm_smmu_make_s1_cd(struct arm_smmu_cd *target,
--
2.43.2