Messages in this thread | | | Subject | Re: [PATCH] x86/cpuid: expose AVX512_4VNNIW and AVX512_4FMAPS features to kvm guest | From | Paolo Bonzini <> | Date | Mon, 31 Oct 2016 11:47:48 +0100 |
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On 31/10/2016 11:30, Borislav Petkov wrote: > On Mon, Oct 31, 2016 at 10:18:41AM +0000, Luc, Piotr wrote: >> The cpuid_mask function, which usually used in kvm, read bit from this >> x86_capabity and mask out. This prevents passing disabled features to >> guest. If we use cpu_count instead, which reports bits directly from > > Ah, you mean cpuid_count(). > >> CPU, then the bits of features that are disabled in host are passed to >> guest as enabled. This seems be inconsistent. > > Ok, I see what you mean. > > So I guess we'll have to iterate over the cpuid_bits[] array and > recreate the CPUID leaf for KVM instead, as I suggested earlier.
Yes, indeed. :(
The information is all in arch/x86/kernel/cpu/scattered.c's cpuid_bits array. Borislav, would it be okay to export the cpuid_regs enum?
Paolo
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