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| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-12-18 21:47:54 +0100 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2017-01-09 14:48:01 +0100 |
| commit | b3c045d33218fe291b04d30e24b6eab0431987e6 (patch) | |
| tree | b803f5aadf5501746a7f56d985e6b52eb50083da /arch/x86/kvm/lapic.c | |
| parent | KVM: vmx: speed up TPR below threshold vmexits (diff) | |
| download | linux-b3c045d33218fe291b04d30e24b6eab0431987e6.tar.xz linux-b3c045d33218fe291b04d30e24b6eab0431987e6.zip | |
KVM: lapic: remove unnecessary KVM_REQ_EVENT on PPR update
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>
Diffstat (limited to 'arch/x86/kvm/lapic.c')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 36 |
1 files changed, 24 insertions, 12 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 6b1d3a76c1d0..a878e33119a3 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -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) |