Re: [PART1 RFC v2 06/10] svm: Add interrupt injection via AVIC

From: Suravee Suthikulpanit
Date: Mon Mar 14 2016 - 05:42:10 EST


On 03/09/2016 11:00 PM, Radim KrÄmÃÅ wrote:
2016-03-09 12:10+0100, Paolo Bonzini:
On 08/03/2016 22:54, Radim KrÄmÃÅ wrote:
2016-03-07 16:36+0100, Paolo Bonzini:
On 04/03/2016 21:46, Suravee Suthikulpanit wrote:
+static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
+ struct vcpu_svm *svm = to_svm(vcpu);
+ kvm_lapic_set_vector(vec, avic_get_bk_page_entry(svm, APIC_IRR));

(I think that smp_mb here would make sense, even though we're fine now
thanks to re-checking vcpu->mode in kvm_vcpu_kick.

Right, though only a smp_mb__after_atomic() is required (which is a
compiler barrier). It is similarly required in vmx.

True, kvm_lapic_set_vector uses a lock prefix.

(I thought it behaves like atomic_set, which would require MFENCE for
correct ordering here ... I don't like smp_mb__after_atomic much
because of the discrepancy on some atomic operations.)

So, should i just use smb_mb() in this case?