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KVM: x86: Grab lapic_timer in a local variable to cleanup periodic code

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Stash apic->lapic_timer in a local "ktimer" variable in
advance_periodic_target_expiration() to eliminate a few unaligned wraps,
and to make the code easier to read overall.

No functional change intended.

Link: https://patch.msgid.link/20251113205114.1647493-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson
2025-11-13 12:51:14 -08:00
parent 18ab3fc8e8
commit a091fe60c2
1 changed files with 8 additions and 8 deletions
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16
arch/x86/kvm/lapic.c
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@@ -2126,6 +2126,7 @@ static bool set_target_expiration(struct kvm_lapic *apic, u32 count_reg)
static void advance_periodic_target_expiration(struct kvm_lapic *apic)
{
struct kvm_timer *ktimer = &apic->lapic_timer;
ktime_t now = ktime_get();
u64 tscl = rdtsc();
ktime_t delta;
@@ -2137,9 +2138,8 @@ static void advance_periodic_target_expiration(struct kvm_lapic *apic)
* over time as differences in the periods accumulate, e.g. due to
* differences in the underlying clocks or numerical approximation errors.
*/
apic->lapic_timer.target_expiration =
ktime_add_ns(apic->lapic_timer.target_expiration,
apic->lapic_timer.period);
ktimer->target_expiration = ktime_add_ns(ktimer->target_expiration,
ktimer->period);
/*
* If the new expiration is in the past, e.g. because userspace stopped
@@ -2150,17 +2150,17 @@ static void advance_periodic_target_expiration(struct kvm_lapic *apic)
* past will do nothing more than waste host cycles, and can even lead
* to a hard lockup in extreme cases.
*/
if (ktime_before(apic->lapic_timer.target_expiration, now))
apic->lapic_timer.target_expiration = now;
if (ktime_before(ktimer->target_expiration, now))
ktimer->target_expiration = now;
/*
* Note, ensuring the expiration isn't in the past also prevents delta
* from going negative, which could cause the TSC deadline to become
* excessively large due to it an unsigned value.
*/
delta = ktime_sub(apic->lapic_timer.target_expiration, now);
apic->lapic_timer.tscdeadline = kvm_read_l1_tsc(apic->vcpu, tscl) +
nsec_to_cycles(apic->vcpu, delta);
delta = ktime_sub(ktimer->target_expiration, now);
ktimer->tscdeadline = kvm_read_l1_tsc(apic->vcpu, tscl) +
nsec_to_cycles(apic->vcpu, delta);
}
static void start_sw_period(struct kvm_lapic *apic)