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-rw-r--r--arch/x86/include/uapi/asm/kvm_para.h9
-rw-r--r--arch/x86/kvm/x86.c66
2 files changed, 75 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 1421a6585126..cff0bb6556f8 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -50,6 +50,15 @@ struct kvm_steal_time {
__u32 pad[11];
};
+#define KVM_CLOCK_PAIRING_WALLCLOCK 0
+struct kvm_clock_pairing {
+ __s64 sec;
+ __s64 nsec;
+ __u64 tsc;
+ __u32 flags;
+ __u32 pad[9];
+};
+
#define KVM_STEAL_ALIGNMENT_BITS 5
#define KVM_STEAL_VALID_BITS ((-1ULL << (KVM_STEAL_ALIGNMENT_BITS + 1)))
#define KVM_STEAL_RESERVED_MASK (((1 << KVM_STEAL_ALIGNMENT_BITS) - 1 ) << 1)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4fd4d4f35caf..09e5d31dac98 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1142,6 +1142,7 @@ struct pvclock_gtod_data {
u64 boot_ns;
u64 nsec_base;
+ u64 wall_time_sec;
};
static struct pvclock_gtod_data pvclock_gtod_data;
@@ -1165,6 +1166,8 @@ static void update_pvclock_gtod(struct timekeeper *tk)
vdata->boot_ns = boot_ns;
vdata->nsec_base = tk->tkr_mono.xtime_nsec;
+ vdata->wall_time_sec = tk->xtime_sec;
+
write_seqcount_end(&vdata->seq);
}
#endif
@@ -1626,6 +1629,28 @@ static int do_monotonic_boot(s64 *t, u64 *cycle_now)
return mode;
}
+static int do_realtime(struct timespec *ts, u64 *cycle_now)
+{
+ struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
+ unsigned long seq;
+ int mode;
+ u64 ns;
+
+ do {
+ seq = read_seqcount_begin(&gtod->seq);
+ mode = gtod->clock.vclock_mode;
+ ts->tv_sec = gtod->wall_time_sec;
+ ns = gtod->nsec_base;
+ ns += vgettsc(cycle_now);
+ ns >>= gtod->clock.shift;
+ } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+
+ ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+ ts->tv_nsec = ns;
+
+ return mode;
+}
+
/* returns true if host is using tsc clocksource */
static bool kvm_get_time_and_clockread(s64 *kernel_ns, u64 *cycle_now)
{
@@ -1635,6 +1660,17 @@ static bool kvm_get_time_and_clockread(s64 *kernel_ns, u64 *cycle_now)
return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC;
}
+
+/* returns true if host is using tsc clocksource */
+static bool kvm_get_walltime_and_clockread(struct timespec *ts,
+ u64 *cycle_now)
+{
+ /* checked again under seqlock below */
+ if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC)
+ return false;
+
+ return do_realtime(ts, cycle_now) == VCLOCK_TSC;
+}
#endif
/*
@@ -6112,6 +6148,33 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_emulate_halt);
+static int kvm_pv_clock_pairing(struct kvm_vcpu *vcpu, gpa_t paddr,
+ unsigned long clock_type)
+{
+ struct kvm_clock_pairing clock_pairing;
+ struct timespec ts;
+ cycle_t cycle;
+ int ret;
+
+ if (clock_type != KVM_CLOCK_PAIRING_WALLCLOCK)
+ return -KVM_EOPNOTSUPP;
+
+ if (kvm_get_walltime_and_clockread(&ts, &cycle) == false)
+ return -KVM_EOPNOTSUPP;
+
+ clock_pairing.sec = ts.tv_sec;
+ clock_pairing.nsec = ts.tv_nsec;
+ clock_pairing.tsc = kvm_read_l1_tsc(vcpu, cycle);
+ clock_pairing.flags = 0;
+
+ ret = 0;
+ if (kvm_write_guest(vcpu->kvm, paddr, &clock_pairing,
+ sizeof(struct kvm_clock_pairing)))
+ ret = -KVM_EFAULT;
+
+ return ret;
+}
+
/*
* kvm_pv_kick_cpu_op: Kick a vcpu.
*
@@ -6176,6 +6239,9 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1);
ret = 0;
break;
+ case KVM_HC_CLOCK_PAIRING:
+ ret = kvm_pv_clock_pairing(vcpu, a0, a1);
+ break;
default:
ret = -KVM_ENOSYS;
break;