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Commit a323b409 authored by Radim Krčmář's avatar Radim Krčmář Committed by Paolo Bonzini
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KVM: x86: detect LVTT changes under APICv 



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: default avatarRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e462755c

arch/x86/kvm/lapic.c

+8 −4
Original line number Diff line number Diff line
@@ -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));

arch/x86/kvm/lapic.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */