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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Ashok Raj <ashok.raj@intel.com>
Subject: [PATCH v2 2/5] iommu/vt-d: Remove WO permissions on second-level paging entries
Date: Sat, 20 Mar 2021 10:54:12 +0800	[thread overview]
Message-ID: <20210320025415.641201-3-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20210320025415.641201-1-baolu.lu@linux.intel.com>

When the first level page table is used for IOVA translation, it only
supports Read-Only and Read-Write permissions. The Write-Only permission
is not supported as the PRESENT bit (implying Read permission) should
always set. When using second level, we still give separate permissions
that allows WriteOnly which seems inconsistent and awkward. We want to
have consistent behavior. After moving to 1st level, we don't want things
to work sometimes, and break if we use 2nd level for the same mappings.
Hence remove this configuration.

Suggested-by: Ashok Raj <ashok.raj@intel.com>
Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 167219ea8d70..132cbf9f214f 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2304,8 +2304,9 @@ __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
 		return -EINVAL;
 
 	attr = prot & (DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP);
+	attr |= DMA_FL_PTE_PRESENT;
 	if (domain_use_first_level(domain)) {
-		attr |= DMA_FL_PTE_PRESENT | DMA_FL_PTE_XD | DMA_FL_PTE_US;
+		attr |= DMA_FL_PTE_XD | DMA_FL_PTE_US;
 
 		if (domain->domain.type == IOMMU_DOMAIN_DMA) {
 			attr |= DMA_FL_PTE_ACCESS;
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>
Cc: Ashok Raj <ashok.raj@intel.com>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/5] iommu/vt-d: Remove WO permissions on second-level paging entries
Date: Sat, 20 Mar 2021 10:54:12 +0800	[thread overview]
Message-ID: <20210320025415.641201-3-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20210320025415.641201-1-baolu.lu@linux.intel.com>

When the first level page table is used for IOVA translation, it only
supports Read-Only and Read-Write permissions. The Write-Only permission
is not supported as the PRESENT bit (implying Read permission) should
always set. When using second level, we still give separate permissions
that allows WriteOnly which seems inconsistent and awkward. We want to
have consistent behavior. After moving to 1st level, we don't want things
to work sometimes, and break if we use 2nd level for the same mappings.
Hence remove this configuration.

Suggested-by: Ashok Raj <ashok.raj@intel.com>
Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 167219ea8d70..132cbf9f214f 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2304,8 +2304,9 @@ __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
 		return -EINVAL;
 
 	attr = prot & (DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP);
+	attr |= DMA_FL_PTE_PRESENT;
 	if (domain_use_first_level(domain)) {
-		attr |= DMA_FL_PTE_PRESENT | DMA_FL_PTE_XD | DMA_FL_PTE_US;
+		attr |= DMA_FL_PTE_XD | DMA_FL_PTE_US;
 
 		if (domain->domain.type == IOMMU_DOMAIN_DMA) {
 			attr |= DMA_FL_PTE_ACCESS;
-- 
2.25.1

_______________________________________________
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iommu@lists.linux-foundation.org
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  parent reply	other threads:[~2021-03-20  3:04 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-20  2:54 [PATCH v2 0/5] iommu/vt-d: Several misc fixes Lu Baolu
2021-03-20  2:54 ` Lu Baolu
2021-03-20  2:54 ` [PATCH v2 1/5] iommu/vt-d: Report the right page fault address Lu Baolu
2021-03-20  2:54   ` Lu Baolu
2021-03-20  2:54 ` Lu Baolu [this message]
2021-03-20  2:54   ` [PATCH v2 2/5] iommu/vt-d: Remove WO permissions on second-level paging entries Lu Baolu
2021-03-20  2:54 ` [PATCH v2 3/5] iommu/vt-d: Invalidate PASID cache when root/context entry changed Lu Baolu
2021-03-20  2:54   ` Lu Baolu
2021-03-20  2:54 ` [PATCH v2 4/5] iommu/vt-d: Use user privilege for RID2PASID translation Lu Baolu
2021-03-20  2:54   ` Lu Baolu
2021-04-06  0:58   ` Lu Baolu
2021-04-06  0:58     ` Lu Baolu
2021-03-20  2:54 ` [PATCH v2 5/5] iommu/vt-d: Avoid unnecessary cache flush in pasid entry teardown Lu Baolu
2021-03-20  2:54   ` Lu Baolu

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