> -----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@xxxxxxxxxx; Alex > Williamson; Jiang Liu > Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; 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. 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
