linux-kernel - [PATCH v2 2/2] iommu/vt-d: Remove two WARN_ON in domain_context_mapping

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Message-Id: <20230602020520.224465-3-yanfei.xu@intel.com>
Date:   Fri,  2 Jun 2023 10:05:20 +0800
From:   Yanfei Xu <yanfei.xu@...el.com>
To:     dwmw2@...radead.org, baolu.lu@...ux.intel.com, joro@...tes.org,
        will@...nel.org, robin.murphy@....com
Cc:     iommu@...ts.linux.dev, linux-kernel@...r.kernel.org,
        yanfei.xu@...el.com
Subject: [PATCH v2 2/2] iommu/vt-d: Remove two WARN_ON in domain_context_mapping_one()

Remove the WARN_ON(did == 0) as the domain id 0 is reserved and
set once the domain_ids is allocated. So iommu_init_domains will
never return 0.

Remvoe the WARN_ON(!table) as this pointer will be accessed in
the following code, if empty "table" really happens, the kernel
will report a NULL pointer reference warning at the first place.

Signed-off-by: Yanfei Xu <yanfei.xu@...el.com>
---
 drivers/iommu/intel/iommu.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index e9188d045609..3953dd69200d 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1897,8 +1897,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 	struct context_entry *context;
 	int ret;
 
-	WARN_ON(did == 0);
-
 	if (hw_pass_through && domain_type_is_si(domain))
 		translation = CONTEXT_TT_PASS_THROUGH;
 
@@ -1944,8 +1942,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 	if (sm_supported(iommu)) {
 		unsigned long pds;
 
-		WARN_ON(!table);
-
 		/* Setup the PASID DIR pointer: */
 		pds = context_get_sm_pds(table);
 		context->lo = (u64)virt_to_phys(table->table) |
-- 
2.34.1