> -----Original Message----- > From: Yang Zhang [mailto:yang.zhang...@gmail.com] > Sent: Thursday, January 21, 2016 11:06 AM > To: Wu, Feng <feng...@intel.com>; pbonz...@redhat.com; > rkrc...@redhat.com > Cc: linux-kernel@vger.kernel.org; k...@vger.kernel.org > Subject: Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the > interrupt is not single-destination > > On 2016/1/20 9:42, Feng Wu wrote: > > When the interrupt is not single destination any more, we need > > to change back IRTE to remapped mode explicitly. > > > > Signed-off-by: Feng Wu <feng...@intel.com> > > --- > > arch/x86/kvm/vmx.c | 11 ++++++++++- > > 1 file changed, 10 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > > index e2951b6..13d14d4 100644 > > --- a/arch/x86/kvm/vmx.c > > +++ b/arch/x86/kvm/vmx.c > > @@ -10764,8 +10764,17 @@ static int vmx_update_pi_irte(struct kvm > *kvm, unsigned int host_irq, > > */ > > > > kvm_set_msi_irq(e, &irq); > > - if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) > > + if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) { > > + /* > > + * Make sure the IRTE is in remapped mode if > > + * we don't handle it in posted mode. > > + */ > > + pi_set_sn(vcpu_to_pi_desc(vcpu)); > > + ret = irq_set_vcpu_affinity(host_irq, NULL); > > + pi_clear_sn(vcpu_to_pi_desc(vcpu)); > > + > > continue; > > + } > > > > vcpu_info.pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu)); > > vcpu_info.vector = irq.vector; > > > > I am still feel weird with this change: according the semantic of VT-d > posted interrupt, the interrupt will injected to guest through posted > notification and /proc/interrupts shows the same meaning. But now, > without being aware of user, the interrupt changes to legacy way and it > appears on different entry on /proc/interrupts. It looks weird.
I don't think it has problem here, IMO, this is exactly how it works. There should be different entry for the interrupts in VT-d PI mode and leagcy mode. For VT-d PI mode, it is delivered by notification event, for legacy mode, it is delivered by VFIO. Thanks, Feng > > Any comments? Paolo. > > -- > best regards > yang
