[PATCH 6/7] iommu/amd: Do not support IOMMU_DOMAIN_IDENTITY when SNP is enabled

[Suravee Suthikulpanit via iommu <iommu@lists.linux-foundation.org>]

Since DTE[Mode]=0 is prohibited on system, which enables SNP,
the passthrough domain (IOMMU_DOMAIN_IDENTITY) is not support.
Instead, only support IOMMU_DOMAIN_DMA[_FQ] domains.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/iommu.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index ca4647f04382..ecde9e08102d 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2379,6 +2379,17 @@ static int amd_iommu_def_domain_type(struct device *dev)
 	return 0;
 }
 
+static bool amd_iommu_domain_type_supported(struct device *dev, int type)
+{
+	/*
+	 * Since DTE[Mode]=0 is prohibited on SNP-enabled system,
+	 * default to use IOMMU_DOMAIN_DMA[_FQ].
+	 */
+	if (amd_iommu_snp_en && (type == IOMMU_DOMAIN_IDENTITY))
+		return false;
+	return true;
+}
+
 struct iommu_ops amd_iommu_ops = {
 	.capable = amd_iommu_capable,
 	.domain_alloc = amd_iommu_domain_alloc,
@@ -2391,6 +2402,7 @@ struct iommu_ops amd_iommu_ops = {
 	.is_attach_deferred = amd_iommu_is_attach_deferred,
 	.pgsize_bitmap	= AMD_IOMMU_PGSIZES,
 	.def_domain_type = amd_iommu_def_domain_type,
+	.domain_type_supported = amd_iommu_domain_type_supported,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= amd_iommu_attach_device,
 		.detach_dev	= amd_iommu_detach_device,
-- 
2.32.0

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