> -----Original Message-----
> From: linux-kernel-ow...@vger.kernel.org
> [mailto:linux-kernel-ow...@vger.kernel.org] On Behalf Of Paolo Bonzini
> Sent: Thursday, December 18, 2014 1:43 AM
> To: Wu, Feng; Thomas Gleixner; Ingo Molnar; H. Peter Anvin; x...@kernel.org;
> Gleb Natapov; Paolo Bonzini; dw...@infradead.org; j...@8bytes.org; Alex
> Williamson; Jiang Liu
> Cc: io...@lists.linux-foundation.org; linux-ker...@vger.kernel.org; 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-ral2jqcrhueavxtiumw...@public.gmane.org>
> > ---
> > 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
> > --
> --
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