Messages in this thread | | | Subject | Re: [PATCH v5 15/28] x86/arch_prctl: Create ARCH_GET_XSTATE/ARCH_PUT_XSTATE | From | Dave Hansen <> | Date | Tue, 25 May 2021 10:33:25 -0700 |
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On 5/25/21 10:27 AM, Borislav Petkov wrote: > On Mon, May 24, 2021 at 07:10:57PM -0400, Len Brown wrote: >> 1. CPUID has AMX >> 2. XCR0 has AMX >> 3. Linux permission has been requested and granted to this process > Actually, you want *only* 3 as 1 is a bad idea - we're in this mess > because userspace does feature detection on its own even when kernel > support is needed. > > When Linux grants the permission, 1 and 2 should be implicitly given.
We did this for pkeys. Essentially, we said, "don't bother with CPUID.OSPKE and XCRO[PKRU] checking". Just call alloc_pkey() and we'll do the checking for you. One stop shopping.
So far, it's worked well.
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