提交 16e8d74d 编写于 作者: M Marcelo Tosatti

KVM: x86: notifier for clocksource changes

Register a notifier for clocksource change event. In case
the host switches to clock other than TSC, disable master
clock usage.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
上级 e0b306fe
......@@ -46,6 +46,8 @@
#include <linux/uaccess.h>
#include <linux/hash.h>
#include <linux/pci.h>
#include <linux/timekeeper_internal.h>
#include <linux/pvclock_gtod.h>
#include <trace/events/kvm.h>
#define CREATE_TRACE_POINTS
......@@ -901,6 +903,55 @@ static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
return kvm_set_msr(vcpu, index, *data);
}
#ifdef CONFIG_X86_64
struct pvclock_gtod_data {
seqcount_t seq;
struct { /* extract of a clocksource struct */
int vclock_mode;
cycle_t cycle_last;
cycle_t mask;
u32 mult;
u32 shift;
} clock;
/* open coded 'struct timespec' */
u64 monotonic_time_snsec;
time_t monotonic_time_sec;
};
static struct pvclock_gtod_data pvclock_gtod_data;
static void update_pvclock_gtod(struct timekeeper *tk)
{
struct pvclock_gtod_data *vdata = &pvclock_gtod_data;
write_seqcount_begin(&vdata->seq);
/* copy pvclock gtod data */
vdata->clock.vclock_mode = tk->clock->archdata.vclock_mode;
vdata->clock.cycle_last = tk->clock->cycle_last;
vdata->clock.mask = tk->clock->mask;
vdata->clock.mult = tk->mult;
vdata->clock.shift = tk->shift;
vdata->monotonic_time_sec = tk->xtime_sec
+ tk->wall_to_monotonic.tv_sec;
vdata->monotonic_time_snsec = tk->xtime_nsec
+ (tk->wall_to_monotonic.tv_nsec
<< tk->shift);
while (vdata->monotonic_time_snsec >=
(((u64)NSEC_PER_SEC) << tk->shift)) {
vdata->monotonic_time_snsec -=
((u64)NSEC_PER_SEC) << tk->shift;
vdata->monotonic_time_sec++;
}
write_seqcount_end(&vdata->seq);
}
#endif
static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
int version;
......@@ -997,6 +1048,8 @@ static inline u64 get_kernel_ns(void)
return timespec_to_ns(&ts);
}
static atomic_t kvm_guest_has_master_clock = ATOMIC_INIT(0);
static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);
unsigned long max_tsc_khz;
......@@ -1229,7 +1282,6 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
vcpu->last_kernel_ns = kernel_ns;
vcpu->last_guest_tsc = tsc_timestamp;
/*
* The interface expects us to write an even number signaling that the
* update is finished. Since the guest won't see the intermediate
......@@ -4857,6 +4909,39 @@ static void kvm_set_mmio_spte_mask(void)
kvm_mmu_set_mmio_spte_mask(mask);
}
#ifdef CONFIG_X86_64
static void pvclock_gtod_update_fn(struct work_struct *work)
{
}
static DECLARE_WORK(pvclock_gtod_work, pvclock_gtod_update_fn);
/*
* Notification about pvclock gtod data update.
*/
static int pvclock_gtod_notify(struct notifier_block *nb, unsigned long unused,
void *priv)
{
struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
struct timekeeper *tk = priv;
update_pvclock_gtod(tk);
/* disable master clock if host does not trust, or does not
* use, TSC clocksource
*/
if (gtod->clock.vclock_mode != VCLOCK_TSC &&
atomic_read(&kvm_guest_has_master_clock) != 0)
queue_work(system_long_wq, &pvclock_gtod_work);
return 0;
}
static struct notifier_block pvclock_gtod_notifier = {
.notifier_call = pvclock_gtod_notify,
};
#endif
int kvm_arch_init(void *opaque)
{
int r;
......@@ -4898,6 +4983,10 @@ int kvm_arch_init(void *opaque)
host_xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
kvm_lapic_init();
#ifdef CONFIG_X86_64
pvclock_gtod_register_notifier(&pvclock_gtod_notifier);
#endif
return 0;
out:
......@@ -4912,6 +5001,9 @@ void kvm_arch_exit(void)
cpufreq_unregister_notifier(&kvmclock_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
unregister_hotcpu_notifier(&kvmclock_cpu_notifier_block);
#ifdef CONFIG_X86_64
pvclock_gtod_unregister_notifier(&pvclock_gtod_notifier);
#endif
kvm_x86_ops = NULL;
kvm_mmu_module_exit();
}
......
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