Messages in this thread | | | Date | Fri, 3 Mar 2023 09:18:00 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 1/1] iommu/vt-d: Add opt-in for ATS support on discrete devices |
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On Fri, Mar 03, 2023 at 08:19:29AM +0000, Tian, Kevin wrote: > > From: Jason Gunthorpe <jgg@nvidia.com> > > Sent: Thursday, March 2, 2023 1:43 AM > > > > If Intel BIOS's have populated the "satcu" to say that ATS is not > > supported by the HW when the HW supports ATS perfectly fine, then get > > the BIOS fixed or patch the ACPI until it is fixed. The BIOS should > > not be saying that the HW does not support ATS when it does, it is a > > simple BIOS bug. > > > > That is not the purpose of SATC. > > The ATS support in VT-d side is reported in two interfaces: > > 1) "Device-TLB support" in Extended Capability Register; > 2) Root port ATS capability in ACPI ATSR structure; > > A device gets ATS enabled if 1/2 are true and !pdev->untrusted. Same > as SMMU does. > > The main purpose of SATC is to describe which ATS-capable integrated > device meets the requirements of securely using ATS as stated in VT-d > spec 4.4.
Then it should be mapped to pdev->untrusted and possibly pdev->untrusted to be enhanced to be more descriptive.
iommu driver and BIOS should have no role in security policy beyond feeding in data to a common policy engine.
Jason
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