> -----Original Message----- > From: Radim Krčmář [mailto:rkrc...@redhat.com] > Sent: Friday, January 22, 2016 4:17 AM > To: Wu, Feng <feng...@intel.com> > Cc: pbonz...@redhat.com; linux-kernel@vger.kernel.org; > k...@vger.kernel.org > Subject: Re: [PATCH v3 3/4] KVM: x86: Add lowest-priority support for vt-d > posted-interrupts > > 2016-01-20 09:42+0800, Feng Wu: > > Use vector-hashing to deliver lowest-priority interrupts for > > VT-d posted-interrupts. This patch extends kvm_intr_is_single_vcpu() > > to support lowest-priority handling. > > > > Signed-off-by: Feng Wu <feng...@intel.com> > > --- > > v3: > > - Remove unnecessary check in fast irq delivery patch > > - print a error message only once for each guest when we find hardware > > disabled LAPIC during interrupt injection. > > > > diff --git a/arch/x86/include/asm/kvm_host.h > b/arch/x86/include/asm/kvm_host.h > > @@ -1316,8 +1316,8 @@ int x86_set_memory_region(struct kvm *kvm, int > id, gpa_t gpa, u32 size); > > bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu); > > bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu); > > > > -bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq, > > - struct kvm_vcpu **dest_vcpu); > > +bool kvm_intr_can_posting(struct kvm *kvm, struct kvm_lapic_irq *irq, > > I prefer the original one; I think it's better to describe function > than intent in names -- intention should be obvious from its use. > > > + struct kvm_vcpu **dest_vcpu); > > > > void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e, > > struct kvm_lapic_irq *irq); > > diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c > > @@ -300,13 +300,13 @@ out: > > return r; > > } > > > > -bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq, > > - struct kvm_vcpu **dest_vcpu) > > +bool kvm_intr_can_posting(struct kvm *kvm, struct kvm_lapic_irq *irq, > > + struct kvm_vcpu **dest_vcpu) > > { > > int i, r = 0; > > struct kvm_vcpu *vcpu; > > > > - if (kvm_intr_is_single_vcpu_fast(kvm, irq, dest_vcpu)) > > + if (kvm_intr_can_posting_fast(kvm, irq, dest_vcpu)) > > return true; > > There is one pitfall: xAPIC flat logical broadcast returns false,
Do you mean kvm_intr_can_posting_fast() returns false for xAPIC flat logical lowest-priority broadcast? After carefully read the code for several times, I still cannot find the reason, could you please give more hints? BTW, I noticed there is a "if(irq->dest_id == 0xFF) goto out;" in this function, but it is for the physical dest mode. I am not sure you mean this. > but lowest priority is defined for it (practically isn't a broadcast) and > the rest of this function doesn't check for lowest priority, so the > interrupt won't be posted. > > We could modify our _fast functions to cover 0xff in flat logical, but > ignoring this case isn't bad either ... it can happen only with 8 VCPU > guests. Could you please elaborate a bit more why only for the 8 VCPU guests? Thanks a lot! Thanks, Feng
