Re: [PATCH 0/2] KVM: VMX: Avoid RDMSRs in PI x2APIC checks

[Paolo Bonzini]

On 15/01/21 23:03, Sean Christopherson wrote:
> Resurrect a patch[*] from over a year ago to avoid RDMSR in a fairly hot
> path in KVM's posted interrupt support.  Note, in my response to that
> patch, I suggested checking x2apic_supported() as well as x2apic_mode.  I
> have no idea why I suggested that; unless I'm missing something,
> x2apic_mode can never be set if x2apic_supported() is false.
>
> [*] https://lkml.kernel.org/r/20190723130608.26528-1-luferry@xxxxxxx/
>
> Sean Christopherson (2):
>    x86/apic: Export x2apic_mode for use by KVM in "warm" path
>    KVM: VMX: Use x2apic_mode to avoid RDMSR when querying PI state
>
>   arch/x86/kernel/apic/apic.c    | 1 +
>   arch/x86/kvm/vmx/posted_intr.c | 6 +++---
>   2 files changed, 4 insertions(+), 3 deletions(-)

Queued, thanks.

Paolo