On Thu, Aug 10, 2023 at 05:23:37PM +0800, Michael Shavit wrote:

quoted

quoted

@@ -2465,6 +2450,22 @@ 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;
+                             return ret;
+                     }
+             }
+
+             ret = arm_smmu_write_ctx_desc(master, 0, &smmu_domain->cd);
+             if (ret) {
+                     master->domain = NULL;
+                     return ret;

Can you leak the cd tables here if you just allocated them?

The CD table is only de-allocated when the SMMU device is released, so
this isn't "leaked" anymore than on a successful attachment. In a
previous version of this patch, this CD table was even pre-allocated
at probe time but is deferred to first attach following this
discussion: https://lore.kernel.org/lkml/ZMOzs1%2FxoEPX2+vA@nvidia.com/ (local)

Thanks, that makes sense.

quoted

quoted

@@ -2472,10 +2473,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
      spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);

      arm_smmu_enable_ats(master);
-
-out_unlock:
-     mutex_unlock(&smmu_domain->init_mutex);
-     return ret;
+     return 0;
 }

 static int arm_smmu_map_pages(struct iommu_domain *domain, unsigned long iova,

@@ -2719,6 +2717,8 @@ 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)

Why are you checking 'cdtab_dma' here instead of just 'cdtab'?

cd_table is statically allocated as part of the arm_smmu_master
struct. I suppose it could be allocated by arm_smmu_alloc_cd_tables()
instead?

I just mean you could check 'master->cd_table.cdtab' like you do in other
places. The DMA pointer is supposed to be opaque.

Will

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