Re: [RESEND PATCH 5/6] KVM: x86/VMX: add kvm_vmx_reinject_nmi_irq() for NMI/IRQ reinjection

Paolo Bonzini
2022-11-11T12:50:26Z

On 11/11/22 13:19, Peter Zijlstra wrote:
> On Fri, Nov 11, 2022 at 01:04:27PM +0100, Paolo Bonzini wrote:
>> On Intel you can optionally make it hold onto IRQs, but NMIs are always
>> eaten by the VMEXIT and have to be reinjected manually.
>
> That 'optionally' thing worries me -- as in, KVM is currently
> opting-out?

Yes, because "If the “process posted interrupts” VM-execution control is
1, the “acknowledge interrupt on exit” VM-exit control is 1" (SDM
26.2.1.1, checks on VM-Execution Control Fields). Ipse dixit. Posted
interrupts are available and used on all processors since I think Ivy
Bridge.

(sorry about splitting the replies across two threads)

Paolo