Messages in this thread | | | Subject | Re: [PATCH v6 00/12] SVM cleanup and INVPCID feature support | From | Paolo Bonzini <> | Date | Wed, 24 Mar 2021 22:59:29 +0100 |
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On 24/03/21 22:21, Borislav Petkov wrote: > if (kaiser_enabled) > invpcid_flush_one(X86_CR3_PCID_ASID_USER, addr); > + else > + asm volatile("invlpg (%0)" ::"r" (addr) : "memory"); > + > invpcid_flush_one(X86_CR3_PCID_ASID_KERN, addr); > }
I think the kernel ASID flush can also be moved under the "if"?
> and the reason why it does, IMHO, is because on AMD, kaiser_enabled is > false because AMD is not affected by Meltdown, which means, there's no > user/kernel pagetables split. > > And that also means, you have global TLB entries which means that if you > look at that __native_flush_tlb_single() function, it needs to flush > global TLB entries on CPUs with X86_FEATURE_INVPCID_SINGLE by doing an > INVLPG in the kaiser_enabled=0 case. Errgo, the above hunk.
Makes sense.
Paolo
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