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Subject[PATCH] KVM: x86: fix lapic.timer_mode on restore
Date
lapic.timer_mode was not properly initialized after migration, which
broke few useful things, like login, by making every sleep eternal.

Fix this by calling apic_update_lvtt in kvm_apic_post_state_restore.

There are other slowpaths that update lvtt, so this patch makes sure
something similar doesn't happen again by calling apic_update_lvtt
after every modification.

Cc: stable@vger.kernel.org
Fixes: f30ebc312ca9 ("KVM: x86: optimize some accesses to LVTT and SPIV")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
arch/x86/kvm/lapic.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index beeef05bb4d9..36e9de1b4127 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1103,6 +1103,17 @@ static void update_divide_count(struct kvm_lapic *apic)
apic->divide_count);
}

+static void apic_update_lvtt(struct kvm_lapic *apic)
+{
+ u32 timer_mode = kvm_apic_get_reg(apic, APIC_LVTT) &
+ 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);
+ }
+}
+
static void apic_timer_expired(struct kvm_lapic *apic)
{
struct kvm_vcpu *vcpu = apic->vcpu;
@@ -1311,6 +1322,7 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
apic_set_reg(apic, APIC_LVTT + 0x10 * i,
lvt_val | APIC_LVT_MASKED);
}
+ apic_update_lvtt(apic);
atomic_set(&apic->lapic_timer.pending, 0);

}
@@ -1343,20 +1355,13 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)

break;

- 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);
- }
-
+ case APIC_LVTT:
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);
+ apic_update_lvtt(apic);
break;
- }

case APIC_TMICT:
if (apic_lvtt_tscdeadline(apic))
@@ -1588,7 +1593,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)

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_update_lvtt(apic);
if (!(vcpu->kvm->arch.disabled_quirks & KVM_QUIRK_LINT0_REENABLED))
apic_set_reg(apic, APIC_LVT0,
SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
@@ -1816,6 +1821,7 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,

apic_update_ppr(apic);
hrtimer_cancel(&apic->lapic_timer.timer);
+ apic_update_lvtt(apic);
update_divide_count(apic);
start_apic_timer(apic);
apic->irr_pending = true;
--
2.4.2


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