Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
  KVM: Use new smp_call_function_mask() in kvm_flush_remote_tlbs()
  sched: don't clear PF_VCPU in scheduler
  KVM: Improve local apic timer wraparound handling
  KVM: Fix local apic timer divide by zero
  KVM: Move kvm_guest_exit() after local_irq_enable()
  KVM: x86 emulator: fix access registers for instructions with ModR/M byte and Mod = 3
  KVM: VMX: Force vm86 mode if setting flags during real mode
  KVM: x86 emulator: implement 'movnti mem, reg'
  KVM: VMX: Reset mmu context when entering real mode
  KVM: VMX: Handle NMIs before enabling interrupts and preemption
  KVM: MMU: Set shadow pte atomically in mmu_pte_write_zap_pte()
  KVM: x86 emulator: fix repne/repnz decoding
  KVM: x86 emulator: fix merge screwup due to emulator split

1 files changed, 27 insertions, 11 deletions

diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
index a190587..238fcad 100644
--- a/drivers/kvm/lapic.c
+++ b/drivers/kvm/lapic.c
@@ -494,12 +494,19 @@ static void apic_send_ipi(struct kvm_lapic *apic)
 
 static u32 apic_get_tmcct(struct kvm_lapic *apic)
 {
-	u32 counter_passed;
-	ktime_t passed, now = apic->timer.dev.base->get_time();
-	u32 tmcct = apic_get_reg(apic, APIC_TMICT);
+	u64 counter_passed;
+	ktime_t passed, now;
+	u32 tmcct;
 
 	ASSERT(apic != NULL);
 
+	now = apic->timer.dev.base->get_time();
+	tmcct = apic_get_reg(apic, APIC_TMICT);
+
+	/* if initial count is 0, current count should also be 0 */
+	if (tmcct == 0)
+		return 0;
+
 	if (unlikely(ktime_to_ns(now) <=
 		ktime_to_ns(apic->timer.last_update))) {
 		/* Wrap around */
@@ -514,15 +521,24 @@ static u32 apic_get_tmcct(struct kvm_lapic *apic)
 
 	counter_passed = div64_64(ktime_to_ns(passed),
 				  (APIC_BUS_CYCLE_NS * apic->timer.divide_count));
-	tmcct -= counter_passed;
 
-	if (tmcct <= 0) {
-		if (unlikely(!apic_lvtt_period(apic)))
+	if (counter_passed > tmcct) {
+		if (unlikely(!apic_lvtt_period(apic))) {
+			/* one-shot timers stick at 0 until reset */
 			tmcct = 0;
-		else
-			do {
-				tmcct += apic_get_reg(apic, APIC_TMICT);
-			} while (tmcct <= 0);
+		} else {
+			/*
+			 * periodic timers reset to APIC_TMICT when they
+			 * hit 0. The while loop simulates this happening N
+			 * times. (counter_passed %= tmcct) would also work,
+			 * but might be slower or not work on 32-bit??
+			 */
+			while (counter_passed > tmcct)
+				counter_passed -= tmcct;
+			tmcct -= counter_passed;
+		}
+	} else {
+		tmcct -= counter_passed;
 	}
 
 	return tmcct;
@@ -853,7 +869,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu)
 		apic_set_reg(apic, APIC_ISR + 0x10 * i, 0);
 		apic_set_reg(apic, APIC_TMR + 0x10 * i, 0);
 	}
-	apic->timer.divide_count = 0;
+	update_divide_count(apic);
 	atomic_set(&apic->timer.pending, 0);
 	if (vcpu->vcpu_id == 0)
 		vcpu->apic_base |= MSR_IA32_APICBASE_BSP;