On 27/12/17 12:15, Paolo Bonzini wrote:
On 24/12/2017 17:13, Liran Alon wrote:
+static bool vmx_cpu_has_nested_posted_interrupt(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+ return (vcpu->arch.apicv_active &&
+ is_guest_mode(vcpu) &&
+ vmx->nested.pi_pending &&
+ vmx->nested.pi_desc &&
+ pi_test_on(vmx->nested.pi_desc));
+}
+
/*
* Set up the vmcs's constant host-state fields, i.e., host-state fields that
* will not change in the lifetime of the guest.
@@ -12142,6 +12153,8 @@ static int enable_smi_window(struct kvm_vcpu *vcpu)
.deliver_posted_interrupt = vmx_deliver_posted_interrupt,
.complete_nested_posted_interrupt =
vmx_complete_nested_posted_interrupt,
+ .cpu_has_nested_posted_interrupt =
+ vmx_cpu_has_nested_posted_interrupt,
.set_tss_addr = vmx_set_tss_addr,
.get_tdp_level = get_ept_level,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fa088951afc9..a840f2c9bd66 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8542,7 +8542,8 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
return true;
if (kvm_arch_interrupt_allowed(vcpu) &&
- kvm_cpu_has_interrupt(vcpu))
+ (kvm_cpu_has_interrupt(vcpu) ||
+ kvm_x86_ops->cpu_has_nested_posted_interrupt(vcpu)))
return true;
kvm_cpu_has_interrupt ultimately calls apic_has_interrupt_for_ppr, which
calls kvm_x86_ops->sync_pir_to_irr.
You already have
+ if (is_guest_mode(vcpu))
+ kvm_x86_ops->complete_nested_posted_interrupt(vcpu);
earlier in the series right after a call to kvm_x86_ops->sync_pir_to_irr.
So I wonder if:
1) kvm_x86_ops->complete_nested_posted_interrupt would do the job here as
well, removing the need for the new kvm_x86_ops member;
2) The call to kvm_x86_ops->complete_nested_posted_interrupt actually
applies to all callers of sync_pir_to_irr, which would remove the need for
that other kvm_x86_ops member.
Maybe I misunderstand you, but I don't think this is true.
complete_nested_posted_interrupt() relies on being called at a very
specific call-site: Right before VMEntry and after interrupts are
disabled. It works by issue a self-IPI to cause CPU to actually process
the nested posted-interrupts.
In addition, I don't see how we can utilize the fact that
kvm_cpu_has_interrupt() calls apic_has_interrupt_for_ppr() as
vmx.nested.pi_desc->pir should never be synced into L0 vLAPIC IRR.
In contrast to vmx.pi_desc->pir which does after sync_pir_to_irr().
I'm leaning towards applying patches 1-4, what do you think?
I don't see any reason not to do so if it passes your review :)
Logically these patches are separated from the patches we still debate on.
Regards,
-Liran
Paolo
