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fb2accadaa
To support SNP, IOMMU needs to be enabled, and prohibits IOMMU configurations where DTE[Mode]=0, which means it cannot be supported with IOMMU passthrough domain (a.k.a IOMMU_DOMAIN_IDENTITY), and when AMD IOMMU driver is configured to not use the IOMMU host (v1) page table. Otherwise, RMP table initialization could cause the system to crash. The request to enable SNP support in IOMMU must be done before PCI initialization state of the IOMMU driver because enabling SNP affects how IOMMU driver sets up IOMMU data structures (i.e. DTE). Unlike other IOMMU features, SNP feature does not have an enable bit in the IOMMU control register. Instead, the IOMMU driver introduces an amd_iommu_snp_en variable to track enabling state of SNP. Introduce amd_iommu_snp_enable() for other drivers to request enabling the SNP support in IOMMU, which checks all prerequisites and determines if the feature can be safely enabled. Please see the IOMMU spec section 2.12 for further details. Reviewed-by: Robin Murphy <robin.murphy@arm.com> Co-developed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Link: https://lore.kernel.org/r/20220713225651.20758-7-suravee.suthikulpanit@amd.com Signed-off-by: Joerg Roedel <jroedel@suse.de> |
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| linux | ||
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