From: "Suthikulpanit, Suravee" <suravee.suthikulpanit@amd.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
robin.murphy@arm.com, ashish.kalra@amd.com, vasant.hegde@amd.com,
thomas.lendacky@amd.com
Subject: Re: [PATCH v3 7/7] iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled
Date: Wed, 29 Jun 2022 18:54:34 +0700 [thread overview]
Message-ID: <f21aeb41-1648-24b8-01a5-143b6c99960d@amd.com> (raw)
In-Reply-To: <YrQjHYsEIGN0mtO2@8bytes.org>
On 6/23/2022 3:23 PM, Joerg Roedel wrote:
> On Wed, Jun 22, 2022 at 12:11:31PM -0500, Suravee Suthikulpanit wrote:
>> 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;
>
> IOMMU_v2 APIs could actually be supported with GIOV and IOMMUv2
> page-tables in-use, no?
>
We can support IOMMUv2 iff the v1 table is also setup (i.e. DTE[Mode] != 0).
Currently w/ IOMMU_v2 APIs, the IOMMU sets the mode to zero. Therefore, we
cannot support this use case.
Best Regards,
Suravee
prev parent reply other threads:[~2022-06-29 11:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-22 17:11 [PATCH v3 0/7] iommu/amd: Enforce IOMMU restrictions for SNP-enabled system Suravee Suthikulpanit
2022-06-22 17:11 ` [PATCH v3 1/7] iommu/amd: Warn when found inconsistency EFR mask Suravee Suthikulpanit
2022-06-23 8:22 ` Joerg Roedel
2022-06-29 11:50 ` Suthikulpanit, Suravee
2022-06-22 17:11 ` [PATCH v3 2/7] iommu/amd: Process all IVHDs before enabling IOMMU features Suravee Suthikulpanit
2022-06-22 17:11 ` [PATCH v3 3/7] iommu/amd: Introduce an iommu variable for tracking SNP support status Suravee Suthikulpanit
2022-06-22 17:11 ` [PATCH v3 4/7] iommu/amd: Introduce function to check and enable SNP Suravee Suthikulpanit
2022-06-22 17:11 ` [PATCH v3 5/7] iommu/amd: Set translation valid bit only when IO page tables are in use Suravee Suthikulpanit
2022-06-22 17:11 ` [PATCH v3 6/7] iommu/amd: Do not support IOMMU_DOMAIN_IDENTITY after SNP is enabled Suravee Suthikulpanit
2022-06-22 17:11 ` [PATCH v3 7/7] iommu/amd: Do not support IOMMUv2 APIs when " Suravee Suthikulpanit
2022-06-23 8:23 ` Joerg Roedel
2022-06-29 11:54 ` Suthikulpanit, Suravee [this message]
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