Messages in this thread | | | Subject | Re: [PATCH] KVM: x86: add hint to skip hidden rdpkru under kvm_load_host_xsave_state | From | Dave Hansen <> | Date | Mon, 17 May 2021 10:59:21 -0700 |
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On 5/17/21 10:49 AM, Andy Lutomirski wrote: >> The least awful solution would be to have the NMI handler restore >> the host's PKRU. The NMI handler would need to save/restore the >> register, a la CR2, but the whole thing could be optimized to run >> if and only if the NMI lands in the window where the guest's PKRU >> is loaded. > > Or set a flag causing nmi_uaccess_ok() to return false.
Oh, that doesn't sound too bad. The VMENTER/EXIT paths are also essentially a context switch.
Will widening the window where nmi_uaccess_okay()==false anger any of the perf folks? It looks like perf knows how to handle it nicely.
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