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KVM: lapic: remove unnecessary KVM_REQ_EVENT on PPR update

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PPR needs to be updated whenever on every IRR read because we
may have missed TPR writes that _increased_ PPR.  However, these
writes need not generate KVM_REQ_EVENT, because either KVM_REQ_EVENT
has been set already in __apic_accept_irq, or we are going to
process the interrupt right away.

Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-12-18 21:47:54 +01:00 committed by Radim Krčmář
parent eb90f3417a
commit b3c045d332
1 changed files with 24 additions and 12 deletions
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36
arch/x86/kvm/lapic.c
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@ -570,7 +570,15 @@ static void pv_eoi_clr_pending(struct kvm_vcpu *vcpu)
__clear_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention);
}
static void apic_update_ppr(struct kvm_lapic *apic)
static int apic_has_interrupt_for_ppr(struct kvm_lapic *apic, u32 ppr)
{
int highest_irr = apic_find_highest_irr(apic);
if (highest_irr == -1 || (highest_irr & 0xF0) <= ppr)
return -1;
return highest_irr;
}
static bool __apic_update_ppr(struct kvm_lapic *apic, u32 *new_ppr)
{
u32 tpr, isrv, ppr, old_ppr;
int isr;
@ -588,11 +596,19 @@ static void apic_update_ppr(struct kvm_lapic *apic)
apic_debug("vlapic %p, ppr 0x%x, isr 0x%x, isrv 0x%x",
apic, ppr, isr, isrv);
if (old_ppr != ppr) {
*new_ppr = ppr;
if (old_ppr != ppr)
kvm_lapic_set_reg(apic, APIC_PROCPRI, ppr);
if (ppr < old_ppr)
kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
}
return ppr < old_ppr;
}
static void apic_update_ppr(struct kvm_lapic *apic)
{
u32 ppr;
if (__apic_update_ppr(apic, &ppr))
kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
}
void kvm_apic_update_ppr(struct kvm_vcpu *vcpu)
@ -2056,17 +2072,13 @@ nomem:
int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
int highest_irr;
u32 ppr;
if (!apic_enabled(apic))
return -1;
apic_update_ppr(apic);
highest_irr = apic_find_highest_irr(apic);
if ((highest_irr == -1) ||
((highest_irr & 0xF0) <= kvm_lapic_get_reg(apic, APIC_PROCPRI)))
return -1;
return highest_irr;
__apic_update_ppr(apic, &ppr);
return apic_has_interrupt_for_ppr(apic, ppr);
}
int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)