KVM: x86: Explicitly set new periodic hrtimer expiration in apic_timer_fn()

When restarting an hrtimer to emulate a the guest's APIC timer in periodic
mode, explicitly set the expiration using the target expiration computed
by advance_periodic_target_expiration() instead of adding the period to
the existing timer.  This will allow making adjustments to the expiration,
e.g. to deal with expirations far in the past, without having to implement
the same logic in both advance_periodic_target_expiration() and
apic_timer_fn().

Cc: stable@vger.kernel.org
Signed-off-by: fuqiang wang <fuqiang.wng@gmail.com>
[sean: split to separate patch, write changelog]
Link: https://patch.msgid.link/20251113205114.1647493-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 78b74ba17592bec81408a83baacddc750a12ab61..a5c927e7bae686ae72a0d51f52191be652a8cc8e 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2972,7 +2972,7 @@ static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
 
        if (lapic_is_periodic(apic) && !WARN_ON_ONCE(!apic->lapic_timer.period)) {
                advance_periodic_target_expiration(apic);
-               hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
+               hrtimer_set_expires(&ktimer->timer, ktimer->target_expiration);
                return HRTIMER_RESTART;
        } else
                return HRTIMER_NORESTART;