redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

KVM: deliver PIC interrupt only to vcpu0 

This patch changes the PIC interrupts delivery. Now it is only delivered
to vcpu0 when either condition is met (on vcpu0):
  1. local APIC is hardware disabled
  2. LVT0 is unmasked and configured to delivery mode ExtInt

It fixes the 2x faster wall clock on x86_64 and SMP i386 Linux guests

Signed-off-by: Eddie (Yaozu) Dong <eddie.dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
hifive-unleashed-5.1
Qing He 2007-09-17 14:47:13 +08:00 committed by Avi Kivity
parent 5cd4f6fd85
commit 40487c680d
3 changed files with 28 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/kvm/irq.c
View File

@ -33,8 +33,11 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
struct kvm_pic *s;
if (kvm_apic_has_interrupt(v) == -1) { /* LAPIC */
s = pic_irqchip(v->kvm); /* PIC */
return s->output;
if (kvm_apic_accept_pic_intr(v)) {
s = pic_irqchip(v->kvm); /* PIC */
return s->output;
} else
return 0;
}
return 1;
}
@ -50,9 +53,11 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
vector = kvm_get_apic_interrupt(v); /* APIC */
if (vector == -1) {
s = pic_irqchip(v->kvm);
s->output = 0; /* PIC */
vector = kvm_pic_read_irq(s);
if (kvm_apic_accept_pic_intr(v)) {
s = pic_irqchip(v->kvm);
s->output = 0; /* PIC */
vector = kvm_pic_read_irq(s);
}
}
return vector;
}

1
drivers/kvm/irq.h
View File

@ -135,6 +135,7 @@ do { \
void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu);
int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu);
int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu);
int kvm_create_lapic(struct kvm_vcpu *vcpu);
void kvm_free_apic(struct kvm_lapic *apic);

17
drivers/kvm/lapic.c
View File

@ -788,6 +788,8 @@ static void lapic_reset(struct kvm_vcpu *vcpu)
for (i = 0; i < APIC_LVT_NUM; i++)
apic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED);
apic_set_reg(apic, APIC_LVT0,
SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
apic_set_reg(apic, APIC_DFR, 0xffffffffU);
apic_set_reg(apic, APIC_SPIV, 0xff);
@ -932,6 +934,21 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
return highest_irr;
}
int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
{
u32 lvt0 = apic_get_reg(vcpu->apic, APIC_LVT0);
int r = 0;
if (vcpu->vcpu_id == 0) {
if (!apic_hw_enabled(vcpu->apic))
r = 1;
if ((lvt0 & APIC_LVT_MASKED) == 0 &&
GET_APIC_DELIVERY_MODE(lvt0) == APIC_MODE_EXTINT)
r = 1;
}
return r;
}
void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->apic;