summaryrefslogtreecommitdiffstats
path: root/arch/x86/kvm/lapic.c
diff options
context:
space:
mode:
authorDavid S. Miller <davem@davemloft.net>2018-06-03 09:31:58 -0400
committerDavid S. Miller <davem@davemloft.net>2018-06-03 09:31:58 -0400
commit9c54aeb03a6d65a5834bd92376e921cbac6dfb8f (patch)
tree70441095d58678711d68cfef4934765251425d1f /arch/x86/kvm/lapic.c
parenteaf47b17a77fda841a1102d76c15161ee438b347 (diff)
parent918fe1b3157978ada4267468008c5f89ef101e7d (diff)
downloadlinux-9c54aeb03a6d65a5834bd92376e921cbac6dfb8f.tar.gz
linux-9c54aeb03a6d65a5834bd92376e921cbac6dfb8f.tar.bz2
linux-9c54aeb03a6d65a5834bd92376e921cbac6dfb8f.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Filling in the padding slot in the bpf structure as a bug fix in 'ne' overlapped with actually using that padding area for something in 'net-next'. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/x86/kvm/lapic.c')
-rw-r--r--arch/x86/kvm/lapic.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b74c9c1405b9..3773c4625114 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1522,11 +1522,23 @@ static bool set_target_expiration(struct kvm_lapic *apic)
static void advance_periodic_target_expiration(struct kvm_lapic *apic)
{
- apic->lapic_timer.tscdeadline +=
- nsec_to_cycles(apic->vcpu, apic->lapic_timer.period);
+ ktime_t now = ktime_get();
+ u64 tscl = rdtsc();
+ ktime_t delta;
+
+ /*
+ * Synchronize both deadlines to the same time source or
+ * differences in the periods (caused by differences in the
+ * underlying clocks or numerical approximation errors) will
+ * cause the two to drift apart over time as the errors
+ * accumulate.
+ */
apic->lapic_timer.target_expiration =
ktime_add_ns(apic->lapic_timer.target_expiration,
apic->lapic_timer.period);
+ 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);
}
static void start_sw_period(struct kvm_lapic *apic)