From: Marcelo Tosatti <mtosatti@redhat.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Radim Krcmar <rkrcmar@redhat.com>,
Richard Cochran <richardcochran@gmail.com>,
Miroslav Lichvar <mlichvar@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: [patch 1/3] KVM: x86: provide realtime host clock via vsyscall notifiers
Date: Fri, 13 Jan 2017 10:01:32 -0200 [thread overview]
Message-ID: <20170113120317.948215303@redhat.com> (raw)
In-Reply-To: 20170113120131.086634482@redhat.com
[-- Attachment #1: kvm-do-realtime --]
[-- Type: text/plain, Size: 2074 bytes --]
Expose the realtime host clock and save the TSC value
used for the clock calculation.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
arch/x86/kvm/x86.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
Index: kvm-ptpdriver/arch/x86/kvm/x86.c
===================================================================
--- kvm-ptpdriver.orig/arch/x86/kvm/x86.c 2017-01-13 08:59:03.015895353 -0200
+++ kvm-ptpdriver/arch/x86/kvm/x86.c 2017-01-13 09:04:46.581415259 -0200
@@ -1139,6 +1139,8 @@
u64 boot_ns;
u64 nsec_base;
+ u64 wall_time_sec;
+ u64 wall_time_snsec;
};
static struct pvclock_gtod_data pvclock_gtod_data;
@@ -1162,6 +1164,9 @@
vdata->boot_ns = boot_ns;
vdata->nsec_base = tk->tkr_mono.xtime_nsec;
+ vdata->wall_time_sec = tk->xtime_sec;
+ vdata->wall_time_snsec = tk->tkr_mono.xtime_nsec;
+
write_seqcount_end(&vdata->seq);
}
#endif
@@ -1623,6 +1628,28 @@
return mode;
}
+static int do_realtime(struct timespec *ts, cycle_t *cycle_now)
+{
+ struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
+ unsigned long seq;
+ int mode;
+ u64 ns;
+
+ do {
+ seq = read_seqcount_begin(>od->seq);
+ mode = gtod->clock.vclock_mode;
+ ts->tv_sec = gtod->wall_time_sec;
+ ns = gtod->wall_time_snsec;
+ ns += vgettsc(cycle_now);
+ ns >>= gtod->clock.shift;
+ } while (unlikely(read_seqcount_retry(>od->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, cycle_t *cycle_now)
{
@@ -1632,6 +1659,17 @@
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,
+ cycle_t *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
/*
next prev parent reply other threads:[~2017-01-13 12:03 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-13 12:01 [patch 0/3] KVM virtual PTP driver Marcelo Tosatti
2017-01-13 12:01 ` Marcelo Tosatti [this message]
2017-01-13 15:18 ` [patch 1/3] KVM: x86: provide realtime host clock via vsyscall notifiers Radim Krcmar
2017-01-13 15:34 ` Marcelo Tosatti
2017-01-13 16:28 ` Radim Krcmar
2017-01-13 17:51 ` Marcelo Tosatti
2017-01-16 15:40 ` Radim Krcmar
2017-01-13 15:41 ` Konrad Rzeszutek Wilk
2017-01-13 15:46 ` Marcelo Tosatti
2017-01-13 12:01 ` [patch 2/3] KVM: x86: add KVM_HC_CLOCK_OFFSET hypercall Marcelo Tosatti
2017-01-13 15:31 ` Radim Krcmar
2017-01-13 15:43 ` Marcelo Tosatti
2017-01-13 17:07 ` Radim Krcmar
2017-01-13 17:57 ` Marcelo Tosatti
2017-01-13 12:01 ` [patch 3/3] PTP: add kvm PTP driver Marcelo Tosatti
2017-01-13 15:56 ` Radim Krcmar
2017-01-13 17:40 ` Marcelo Tosatti
2017-01-16 16:26 ` Radim Krcmar
2017-01-16 16:54 ` Radim Krcmar
2017-01-16 17:08 ` Marcelo Tosatti
2017-01-16 17:27 ` Radim Krcmar
2017-01-16 17:39 ` Marcelo Tosatti
2017-01-16 18:01 ` Radim Krcmar
2017-01-16 19:36 ` Marcelo Tosatti
2017-01-16 19:47 ` Marcelo Tosatti
2017-01-16 20:01 ` Marcelo Tosatti
2017-01-17 8:03 ` Miroslav Lichvar
2017-01-17 11:30 ` Marcelo Tosatti
2017-01-17 15:36 ` Radim Krcmar
2017-01-18 12:17 ` Marcelo Tosatti
2017-01-18 12:24 ` Marcelo Tosatti
2017-01-18 12:46 ` Paolo Bonzini
2017-01-18 13:36 ` Miroslav Lichvar
2017-01-18 14:02 ` Paolo Bonzini
2017-01-18 14:50 ` Marcelo Tosatti
2017-01-18 15:35 ` Radim Krcmar
2017-01-18 15:45 ` Paolo Bonzini
2017-01-18 15:57 ` Marcelo Tosatti
2017-01-18 14:24 ` Marcelo Tosatti
2017-01-18 15:54 ` Miroslav Lichvar
2017-01-18 16:07 ` Paolo Bonzini
2017-01-18 16:14 ` Radim Krcmar
2017-01-18 14:37 ` Marcelo Tosatti
2017-01-18 14:53 ` Marcelo Tosatti
2017-01-18 15:20 ` Radim Krcmar
2017-01-18 15:28 ` Marcelo Tosatti
2017-01-20 14:18 ` Radim Krcmar
2017-01-18 15:59 ` Radim Krcmar
2017-01-16 17:04 ` Marcelo Tosatti
2017-01-16 17:46 ` Radim Krcmar
2017-01-16 19:33 ` Marcelo Tosatti
2017-01-14 15:26 ` Richard Cochran
2017-01-16 15:48 ` Radim Krcmar
2017-01-13 18:45 [patch 0/3] KVM virtual PTP driver (v2) Marcelo Tosatti
2017-01-13 18:45 ` [patch 1/3] KVM: x86: provide realtime host clock via vsyscall notifiers Marcelo Tosatti
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