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KVM: x86: detect LVTT changes under APICv

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APIC-write VM exits are "trap-like": they save CS:RIP values for the
instruction after the write, and more importantly, the handler will
already see the new value in the virtual-APIC page.  This means that
apic_reg_write cannot use kvm_apic_get_reg to omit timer cancelation
when mode changes.

timer_mode_mask shouldn't be changing as it depends on cpuid.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Radim Krčmář 2014-10-30 15:06:46 +01:00 committed by Paolo Bonzini
parent e462755cae
commit a323b40982
2 changed files with 9 additions and 4 deletions
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12
arch/x86/kvm/lapic.c
View file

@ -1242,17 +1242,20 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
break;
case APIC_LVTT:
if ((kvm_apic_get_reg(apic, APIC_LVTT) &
apic->lapic_timer.timer_mode_mask) !=
(val & apic->lapic_timer.timer_mode_mask))
case APIC_LVTT: {
u32 timer_mode = val & apic->lapic_timer.timer_mode_mask;
if (apic->lapic_timer.timer_mode != timer_mode) {
apic->lapic_timer.timer_mode = timer_mode;
hrtimer_cancel(&apic->lapic_timer.timer);
}
if (!kvm_apic_sw_enabled(apic))
val |= APIC_LVT_MASKED;
val &= (apic_lvt_mask[0] | apic->lapic_timer.timer_mode_mask);
apic_set_reg(apic, APIC_LVTT, val);
break;
}
case APIC_TMICT:
if (apic_lvtt_tscdeadline(apic))
@ -1483,6 +1486,7 @@ void kvm_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->lapic_timer.timer_mode = 0;
apic_set_reg(apic, APIC_LVT0,
SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));

1
arch/x86/kvm/lapic.h
View file

@ -11,6 +11,7 @@
struct kvm_timer {
struct hrtimer timer;
s64 period; /* unit: ns */
u32 timer_mode;
u32 timer_mode_mask;
u64 tscdeadline;
atomic_t pending; /* accumulated triggered timers */