On 18/12/2014 04:14, Wu, Feng wrote: > > >> -----Original Message----- >> From: linux-kernel-owner@xxxxxxxxxxxxxxx >> [mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Paolo Bonzini >> Sent: Thursday, December 18, 2014 1:43 AM >> To: Wu, Feng; Thomas Gleixner; Ingo Molnar; H. Peter Anvin; x86@xxxxxxxxxx; >> Gleb Natapov; Paolo Bonzini; dwmw2@xxxxxxxxxxxxx; joro-zLv9SwRftAIdnm+yROfE0A@xxxxxxxxxxxxxxxx; Alex >> Williamson; Jiang Liu >> Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel-u79uwXL29TY76Z2rM5mHXA@xxxxxxxxxxxxxxxx; KVM list; >> Eric Auger >> Subject: Re: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set >> >> >> >> On 12/12/2014 16:14, Feng Wu wrote: >>> Currently, we don't support urgent interrupt, all interrupts >>> are recognized as non-urgent interrupt, so we cannot send >>> posted-interrupt when 'SN' is set. >> >> Can this happen? If the vcpu is in guest mode, it cannot have been >> scheduled out, and that's the only case when SN is set. >> >> Paolo > > Currently, the only place where SN is set is vCPU is preempted and waiting for > the next scheduling in the runqueue. But I am not sure whether we need to > set SN for other purpose in future. Adding SN checking here is just to follow > the Spec. non-urgent interrupts are suppressed when SN is set. I would change that to a WARN_ON_ONCE then. Paolo > Thanks, > Feng > >> >>> Signed-off-by: Feng Wu >> <feng.wu-ral2JQCrhuEAvxtiuMwx3w@xxxxxxxxxxxxxxxx> >>> --- >>> arch/x86/kvm/vmx.c | 11 +++++++++-- >>> 1 file changed, 9 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>> index a1c83a2..0aee151 100644 >>> --- a/arch/x86/kvm/vmx.c >>> +++ b/arch/x86/kvm/vmx.c >>> @@ -4401,15 +4401,22 @@ static int vmx_vm_has_apicv(struct kvm *kvm) >>> static void vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int >> vector) >>> { >>> struct vcpu_vmx *vmx = to_vmx(vcpu); >>> - int r; >>> + int r, sn; >>> >>> if (pi_test_and_set_pir(vector, &vmx->pi_desc)) >>> return; >>> >>> + /* >>> + * Currently, we don't support urgent interrupt, all interrupts >>> + * are recognized as non-urgent interrupt, so we cannot send >>> + * posted-interrupt when 'SN' is set. >>> + */ >>> + sn = pi_test_sn(&vmx->pi_desc); >>> + >>> r = pi_test_and_set_on(&vmx->pi_desc); >>> kvm_make_request(KVM_REQ_EVENT, vcpu); >>> #ifdef CONFIG_SMP >>> - if (!r && (vcpu->mode == IN_GUEST_MODE)) >>> + if (!r && !sn && (vcpu->mode == IN_GUEST_MODE)) >>> apic->send_IPI_mask(get_cpu_mask(vcpu->cpu), >>> POSTED_INTR_VECTOR); >>> else >>> -- >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
