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From: Suravee Suthikulpanit via iommu <iommu@lists.linux-foundation.org>
To: <iommu@lists.linux-foundation.org>
Cc: robin.murphy@arm.com, ashish.kalra@amd.com, vasant.hegde@amd.com
Subject: [PATCH 7/7] iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled
Date: Sun, 12 Jun 2022 20:25:02 -0500	[thread overview]
Message-ID: <20220613012502.109918-8-suravee.suthikulpanit@amd.com> (raw)
In-Reply-To: <20220613012502.109918-1-suravee.suthikulpanit@amd.com>

The IOMMUv2 APIs (for supporting shared virtual memory with PASID)
configures the domain with IOMMU v2 page table, and sets DTE[Mode]=0.
This configuration cannot be supported on SNP-enabled system.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/init.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index a9152d3f33bf..1565f0fb955a 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3435,7 +3435,12 @@ __setup("ivrs_acpihid",		parse_ivrs_acpihid);
 
 bool amd_iommu_v2_supported(void)
 {
-	return amd_iommu_v2_present;
+	/*
+	 * Since DTE[Mode]=0 is prohibited on SNP-enabled system
+	 * (i.e. EFR[SNPSup]=1), IOMMUv2 page table cannot be used without
+	 * setting up IOMMUv1 page table.
+	 */
+	return amd_iommu_v2_present && !amd_iommu_snp_en;
 }
 EXPORT_SYMBOL(amd_iommu_v2_supported);
 
-- 
2.32.0

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      parent reply	other threads:[~2022-06-13  1:25 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-13  1:24 [PATCH 0/7] iommu/amd: Enforce IOMMU restrictions for SNP-enabled system Suravee Suthikulpanit via iommu
2022-06-13  1:24 ` [PATCH 1/7] iommu/amd: Process all IVHDs before enabling IOMMU features Suravee Suthikulpanit via iommu
2022-06-13  1:24 ` [PATCH 2/7] iommu/amd: Introduce a global variable for tracking SNP enable status Suravee Suthikulpanit via iommu
2022-06-13  1:24 ` [PATCH 3/7] iommu/amd: Introduce function to check SEV-SNP support Suravee Suthikulpanit via iommu
2022-06-13 14:40   ` Suthikulpanit, Suravee via iommu
2022-06-13  1:24 ` [PATCH 4/7] iommu/amd: Set translation valid bit only when IO page tables are in use Suravee Suthikulpanit via iommu
2022-06-13  1:25 ` [PATCH 5/7] iommu: Add domain_type_supported() callback in iommu_ops Suravee Suthikulpanit via iommu
2022-06-13  9:31   ` Robin Murphy
2022-06-13 14:38     ` Suthikulpanit, Suravee via iommu
2022-06-14  9:51       ` Robin Murphy
2022-06-15  1:25         ` Suthikulpanit, Suravee via iommu
2022-06-13  1:25 ` [PATCH 6/7] iommu/amd: Do not support IOMMU_DOMAIN_IDENTITY when SNP is enabled Suravee Suthikulpanit via iommu
2022-06-13  1:25 ` Suravee Suthikulpanit via iommu [this message]

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