KVM: LAPIC: Write 0 to TMICT should also cancel vmx-preemption timer

mainline inclusion
from mainline-v5.13-rc6
commit e898da78
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4NP0K
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e898da784aed0ea65f7672d941c01dc9b79e6299

-------------------

According to the SDM 10.5.4.1:

  A write of 0 to the initial-count register effectively stops the local
  APIC timer, in both one-shot and periodic mode.

However, the lapic timer oneshot/periodic mode which is emulated by vmx-preemption
timer doesn't stop by writing 0 to TMICT since vmx->hv_deadline_tsc is still
programmed and the guest will receive the spurious timer interrupt later. This
patch fixes it by also cancelling the vmx-preemption timer when writing 0 to
the initial-count register.
Reviewed-by: NSean Christopherson <seanjc@google.com>
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Message-Id: <1623050385-100988-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJingyi Wang <wangjingyi11@huawei.com>
Reviewed-by: NZenghui Yu <yuzenghui@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/x86/kvm/lapic.c

@@ -1492,6 +1492,15 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
 
 static void cancel_hv_timer(struct kvm_lapic *apic);
 
+static void cancel_apic_timer(struct kvm_lapic *apic)
+{
+	hrtimer_cancel(&apic->lapic_timer.timer);
+	preempt_disable();
+	if (apic->lapic_timer.hv_timer_in_use)
+		cancel_hv_timer(apic);
+	preempt_enable();
+}
+
 static void apic_update_lvtt(struct kvm_lapic *apic)
 {
 	u32 timer_mode = kvm_lapic_get_reg(apic, APIC_LVTT) &
@@ -1500,11 +1509,7 @@ static void apic_update_lvtt(struct kvm_lapic *apic)
 	if (apic->lapic_timer.timer_mode != timer_mode) {
 		if (apic_lvtt_tscdeadline(apic) != (timer_mode ==
 				APIC_LVT_TIMER_TSCDEADLINE)) {
-			hrtimer_cancel(&apic->lapic_timer.timer);
-			preempt_disable();
-			if (apic->lapic_timer.hv_timer_in_use)
-				cancel_hv_timer(apic);
-			preempt_enable();
+			cancel_apic_timer(apic);
 			kvm_lapic_set_reg(apic, APIC_TMICT, 0);
 			apic->lapic_timer.period = 0;
 			apic->lapic_timer.tscdeadline = 0;
@@ -2082,7 +2087,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
 		if (apic_lvtt_tscdeadline(apic))
 			break;
 
-		hrtimer_cancel(&apic->lapic_timer.timer);
+		cancel_apic_timer(apic);
 		kvm_lapic_set_reg(apic, APIC_TMICT, val);
 		start_apic_timer(apic);
 		break;