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Diffstat (limited to 'arch/x86/kvm/lapic.c')
-rw-r--r--arch/x86/kvm/lapic.c77
1 files changed, 55 insertions, 22 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 991fdf7fc17f..bd13fdddbdc4 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -70,7 +70,6 @@
#define APIC_BROADCAST 0xFF
#define X2APIC_BROADCAST 0xFFFFFFFFul
-static bool lapic_timer_advance_adjust_done = false;
#define LAPIC_TIMER_ADVANCE_ADJUST_DONE 100
/* step-by-step approximation to mitigate fluctuation */
#define LAPIC_TIMER_ADVANCE_ADJUST_STEP 8
@@ -138,6 +137,7 @@ static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map,
if (offset <= max_apic_id) {
u8 cluster_size = min(max_apic_id - offset + 1, 16U);
+ offset = array_index_nospec(offset, map->max_apic_id + 1);
*cluster = &map->phys_map[offset];
*mask = dest_id & (0xffff >> (16 - cluster_size));
} else {
@@ -901,7 +901,8 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
if (irq->dest_id > map->max_apic_id) {
*bitmap = 0;
} else {
- *dst = &map->phys_map[irq->dest_id];
+ u32 dest_id = array_index_nospec(irq->dest_id, map->max_apic_id + 1);
+ *dst = &map->phys_map[dest_id];
*bitmap = 1;
}
return true;
@@ -1480,14 +1481,32 @@ static bool lapic_timer_int_injected(struct kvm_vcpu *vcpu)
return false;
}
+static inline void __wait_lapic_expire(struct kvm_vcpu *vcpu, u64 guest_cycles)
+{
+ u64 timer_advance_ns = vcpu->arch.apic->lapic_timer.timer_advance_ns;
+
+ /*
+ * If the guest TSC is running at a different ratio than the host, then
+ * convert the delay to nanoseconds to achieve an accurate delay. Note
+ * that __delay() uses delay_tsc whenever the hardware has TSC, thus
+ * always for VMX enabled hardware.
+ */
+ if (vcpu->arch.tsc_scaling_ratio == kvm_default_tsc_scaling_ratio) {
+ __delay(min(guest_cycles,
+ nsec_to_cycles(vcpu, timer_advance_ns)));
+ } else {
+ u64 delay_ns = guest_cycles * 1000000ULL;
+ do_div(delay_ns, vcpu->arch.virtual_tsc_khz);
+ ndelay(min_t(u32, delay_ns, timer_advance_ns));
+ }
+}
+
void wait_lapic_expire(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
+ u32 timer_advance_ns = apic->lapic_timer.timer_advance_ns;
u64 guest_tsc, tsc_deadline, ns;
- if (!lapic_in_kernel(vcpu))
- return;
-
if (apic->lapic_timer.expired_tscdeadline == 0)
return;
@@ -1499,33 +1518,37 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu)
guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
trace_kvm_wait_lapic_expire(vcpu->vcpu_id, guest_tsc - tsc_deadline);
- /* __delay is delay_tsc whenever the hardware has TSC, thus always. */
if (guest_tsc < tsc_deadline)
- __delay(min(tsc_deadline - guest_tsc,
- nsec_to_cycles(vcpu, lapic_timer_advance_ns)));
+ __wait_lapic_expire(vcpu, tsc_deadline - guest_tsc);
- if (!lapic_timer_advance_adjust_done) {
+ if (!apic->lapic_timer.timer_advance_adjust_done) {
/* too early */
if (guest_tsc < tsc_deadline) {
ns = (tsc_deadline - guest_tsc) * 1000000ULL;
do_div(ns, vcpu->arch.virtual_tsc_khz);
- lapic_timer_advance_ns -= min((unsigned int)ns,
- lapic_timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
+ timer_advance_ns -= min((u32)ns,
+ timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
} else {
/* too late */
ns = (guest_tsc - tsc_deadline) * 1000000ULL;
do_div(ns, vcpu->arch.virtual_tsc_khz);
- lapic_timer_advance_ns += min((unsigned int)ns,
- lapic_timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
+ timer_advance_ns += min((u32)ns,
+ timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
}
if (abs(guest_tsc - tsc_deadline) < LAPIC_TIMER_ADVANCE_ADJUST_DONE)
- lapic_timer_advance_adjust_done = true;
+ apic->lapic_timer.timer_advance_adjust_done = true;
+ if (unlikely(timer_advance_ns > 5000)) {
+ timer_advance_ns = 0;
+ apic->lapic_timer.timer_advance_adjust_done = true;
+ }
+ apic->lapic_timer.timer_advance_ns = timer_advance_ns;
}
}
static void start_sw_tscdeadline(struct kvm_lapic *apic)
{
- u64 guest_tsc, tscdeadline = apic->lapic_timer.tscdeadline;
+ struct kvm_timer *ktimer = &apic->lapic_timer;
+ u64 guest_tsc, tscdeadline = ktimer->tscdeadline;
u64 ns = 0;
ktime_t expire;
struct kvm_vcpu *vcpu = apic->vcpu;
@@ -1540,13 +1563,15 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic)
now = ktime_get();
guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
- if (likely(tscdeadline > guest_tsc)) {
- ns = (tscdeadline - guest_tsc) * 1000000ULL;
- do_div(ns, this_tsc_khz);
+
+ ns = (tscdeadline - guest_tsc) * 1000000ULL;
+ do_div(ns, this_tsc_khz);
+
+ if (likely(tscdeadline > guest_tsc) &&
+ likely(ns > apic->lapic_timer.timer_advance_ns)) {
expire = ktime_add_ns(now, ns);
- expire = ktime_sub_ns(expire, lapic_timer_advance_ns);
- hrtimer_start(&apic->lapic_timer.timer,
- expire, HRTIMER_MODE_ABS_PINNED);
+ expire = ktime_sub_ns(expire, ktimer->timer_advance_ns);
+ hrtimer_start(&ktimer->timer, expire, HRTIMER_MODE_ABS_PINNED);
} else
apic_timer_expired(apic);
@@ -2253,7 +2278,7 @@ static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
return HRTIMER_NORESTART;
}
-int kvm_create_lapic(struct kvm_vcpu *vcpu)
+int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns)
{
struct kvm_lapic *apic;
@@ -2277,6 +2302,14 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
HRTIMER_MODE_ABS_PINNED);
apic->lapic_timer.timer.function = apic_timer_fn;
+ if (timer_advance_ns == -1) {
+ apic->lapic_timer.timer_advance_ns = 1000;
+ apic->lapic_timer.timer_advance_adjust_done = false;
+ } else {
+ apic->lapic_timer.timer_advance_ns = timer_advance_ns;
+ apic->lapic_timer.timer_advance_adjust_done = true;
+ }
+
/*
* APIC is created enabled. This will prevent kvm_lapic_set_base from
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-25 07:23:16 +0100