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Groups > linux.kernel > #1563695 > unrolled thread
| Started by | Marcelo Tosatti <mtosatti@redhat.com> |
|---|---|
| First post | 2017-01-20 16:00 +0100 |
| Last post | 2017-01-20 16:00 +0100 |
| Articles | 4 — 1 participant |
Back to article view | Back to linux.kernel
[patch 0/5] KVM virtual PTP driver (v4) Marcelo Tosatti <mtosatti@redhat.com> - 2017-01-20 16:00 +0100
[patch 5/5] PTP: add kvm PTP driver Marcelo Tosatti <mtosatti@redhat.com> - 2017-01-20 16:00 +0100
[patch 5/5] PTP: add kvm PTP driver (v2) Marcelo Tosatti <mtosatti@redhat.com> - 2017-01-20 16:10 +0100
[patch 2/5] KVM: x86: add KVM_HC_CLOCK_OFFSET hypercall Marcelo Tosatti <mtosatti@redhat.com> - 2017-01-20 16:00 +0100
| From | Marcelo Tosatti <mtosatti@redhat.com> |
|---|---|
| Date | 2017-01-20 16:00 +0100 |
| Subject | [patch 0/5] KVM virtual PTP driver (v4) |
| Message-ID | <t1IPw-5I-9@gated-at.bofh.it> |
This patchset implements a virtual PTP driver which allows guest to sync
its clock to the host clock with high precision
(error is < 1us on an idle guest).
Changelog from v3
Patch3:
v2: export kvmclock clocksource structure directly (Paolo)
Patch4:
v2: drop timekeeper spinlock, move back to drivers/ptp/ptp_chardev.c (Paolo)
ptp_clock_gettime: support drivers with crosstimestamp but not
gettime64 callbacks (Paolo)
Patch5:
v4: remove gettime64 callback (Paolo)
Changelog from v2
Cross timestamping, emulation of PTP_SYS_OFFSET with cross timestamping
(Paolo, Miroslav, Radim).
Changelog from v1
Patch1:
v2: unify nsec_base (Radim)
Patch2:
v2: improve documentation (Radim)
change hypercall name to KVM_HC_CLOCK_PAIRING (Radim)
increase padding size
Patch3:
v2: check for kvmclock (Radim)
initialize global variables before device registration (Radim)
PHC0 0 3 377 7 -141ns[ +234ns] +/- 7ns
#* PHC0 0 3 377 5 -197ns[ -403ns] +/- 3ns
#* PHC0 0 3 377 11 +157ns[ +264ns] +/- 3ns
#* PHC0 0 3 377 9 +92ns[ +304ns] +/- 2ns
#* PHC0 0 3 377 7 -102ns[ -164ns] +/- 3ns
#* PHC0 0 3 377 5 -157ns[ -269ns] +/- 2ns
#* PHC0 0 3 377 10 -63ns[ -98ns] +/- 2ns
#* PHC0 0 3 377 8 +351ns[ +399ns] +/- 2ns
#* PHC0 0 3 377 6 +385ns[ +399ns] +/- 4ns
#* PHC0 0 3 377 4 -133ns[ -110ns] +/- 6ns
#* PHC0 0 3 377 10 -59ns[ -90ns] +/- 3ns
#* PHC0 0 3 377 8 -90ns[ +381ns] +/- 9ns
#* PHC0 0 3 377 6 +6ns[ +216ns] +/- 6ns
#* PHC0 0 3 377 4 +166ns[ -666ns] +/- 11ns
#* PHC0 0 3 377 10 -18ns[ +323ns] +/- 10ns
#* PHC0 0 3 377 8 -12ns[ +121ns] +/- 5ns
#* PHC0 0 3 377 5 +4ns[ +218ns] +/- 7ns
#* PHC0 0 3 377 4 +162ns[ -683ns] +/- 11ns
#* PHC0 0 3 377 10 -82ns[ +310ns] +/- 12ns
#* PHC0 0 3 377 7 +5ns[ -320ns] +/- 9ns
#* PHC0 0 3 377 5 -13ns[ +165ns] +/- 7ns
#* PHC0 0 3 377 3 +6ns[ +105ns] +/- 2ns
#* PHC0 0 3 377 9 -19ns[ -67ns] +/- 3ns
#* PHC0 0 3 377 8 +89ns[ +181ns] +/- 3ns
#* PHC0 0 3 377 6 +93ns[ +168ns] +/- 2ns
#* PHC0 0 3 377 4 +100ns[ +154ns] +/- 2ns
#* PHC0 0 3 377 10 -249ns[ +180ns] +/- 7ns
#* PHC0 0 3 377 8 +158ns[ -582ns] +/- 22ns
#* PHC0 0 3 377 6 +10ns[ +213ns] +/- 9ns
#* PHC0 0 3 377 3 -35ns[ +258ns] +/- 5ns
#* PHC0 0 3 377 10 +25ns[ -620ns] +/- 8ns
#* PHC0 0 3 377 7 +13ns[ +153ns] +/- 2ns
[toc] | [next] | [standalone]
| From | Marcelo Tosatti <mtosatti@redhat.com> |
|---|---|
| Date | 2017-01-20 16:00 +0100 |
| Subject | [patch 5/5] PTP: add kvm PTP driver |
| Message-ID | <t1IPx-5I-27@gated-at.bofh.it> |
| In reply to | #1563695 |
Add a driver with gettime method returning hosts realtime clock.
This allows Chrony to synchronize host and guest clocks with
high precision (see results below).
chronyc> sources
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
#* PHC0 0 3 377 4 +162ns[ -683ns] +/- 11ns
To configure Chronyd to use PHC refclock, add the
following line to its configuration file:
refclock PHC /dev/ptpX poll 3 dpoll -2 offset 0
Where /dev/ptpX is the kvmclock PTP clock.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
drivers/ptp/Kconfig | 12 +++
drivers/ptp/Makefile | 1
drivers/ptp/ptp_kvm.c | 179 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 192 insertions(+)
v2: check for kvmclock (Radim)
initialize global variables before device registration (Radim)
v3: use cross timestamps callback (Paolo, Miroslav, Radim)
v4: remove gettime64 callback (Paolo)
Index: kvm-ptpdriver/drivers/ptp/Kconfig
===================================================================
--- kvm-ptpdriver.orig/drivers/ptp/Kconfig 2017-01-20 12:16:32.071150523 -0200
+++ kvm-ptpdriver/drivers/ptp/Kconfig 2017-01-20 12:20:13.862727779 -0200
@@ -90,4 +90,16 @@
To compile this driver as a module, choose M here: the module
will be called ptp_pch.
+config PTP_1588_CLOCK_KVM
+ tristate "KVM virtual PTP clock"
+ depends on PTP_1588_CLOCK
+ depends on KVM_GUEST
+ default y
+ help
+ This driver adds support for using kvm infrastructure as a PTP
+ clock. This clock is only useful if you are using KVM guests.
+
+ To compile this driver as a module, choose M here: the module
+ will be called ptp_kvm.
+
endmenu
Index: kvm-ptpdriver/drivers/ptp/Makefile
===================================================================
--- kvm-ptpdriver.orig/drivers/ptp/Makefile 2017-01-20 12:16:32.071150523 -0200
+++ kvm-ptpdriver/drivers/ptp/Makefile 2017-01-20 12:20:13.862727779 -0200
@@ -6,3 +6,4 @@
obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o
obj-$(CONFIG_PTP_1588_CLOCK_IXP46X) += ptp_ixp46x.o
obj-$(CONFIG_PTP_1588_CLOCK_PCH) += ptp_pch.o
+obj-$(CONFIG_PTP_1588_CLOCK_KVM) += ptp_kvm.o
Index: kvm-ptpdriver/drivers/ptp/ptp_kvm.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ kvm-ptpdriver/drivers/ptp/ptp_kvm.c 2017-01-20 12:20:13.863727782 -0200
@@ -0,0 +1,179 @@
+/*
+ * Virtual PTP 1588 clock for use with KVM guests
+ *
+ * Copyright (C) 2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <uapi/linux/kvm_para.h>
+#include <asm/kvm_para.h>
+#include <asm/pvclock.h>
+#include <asm/kvmclock.h>
+#include <uapi/asm/kvm_para.h>
+
+#include <linux/ptp_clock_kernel.h>
+
+struct kvm_ptp_clock {
+ struct ptp_clock *ptp_clock;
+ struct ptp_clock_info caps;
+};
+
+DEFINE_SPINLOCK(kvm_ptp_lock);
+
+static struct pvclock_vsyscall_time_info *hv_clock;
+
+static struct kvm_clock_offset clock_off;
+static phys_addr_t clock_off_gpa;
+
+static int ptp_kvm_get_time_fn(ktime_t *device_time,
+ struct system_counterval_t *system_counter,
+ void *ctx)
+{
+ unsigned long ret;
+ struct timespec64 tspec;
+ unsigned version;
+ u8 flags;
+ int cpu;
+ struct pvclock_vcpu_time_info *src;
+
+ preempt_disable_notrace();
+ cpu = smp_processor_id();
+ src = &hv_clock[cpu].pvti;
+
+ spin_lock(&kvm_ptp_lock);
+
+ do {
+ /*
+ * We are using a TSC value read in the hosts
+ * kvm_hc_clock_pairing handling.
+ * So any changes to tsc_to_system_mul
+ * and tsc_shift or any other pvclock
+ * data invalidate that measurement.
+ */
+ version = pvclock_read_begin(src);
+
+ ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
+ clock_off_gpa,
+ KVM_CLOCK_PAIRING_WALLCLOCK);
+ if (ret != 0) {
+ pr_err("clock offset hypercall ret %lu\n", ret);
+ spin_unlock(&kvm_ptp_lock);
+ preempt_enable_notrace();
+ return -EOPNOTSUPP;
+ }
+
+ tspec.tv_sec = clock_off.sec;
+ tspec.tv_nsec = clock_off.nsec;
+ ret = __pvclock_read_cycles(src, clock_off.tsc);
+ flags = src->flags;
+ } while (pvclock_read_retry(src, version));
+
+ preempt_enable_notrace();
+
+ system_counter->cycles = ret;
+ system_counter->cs = &kvm_clock;
+
+ tspec.tv_nsec = tspec.tv_nsec;
+
+ *device_time = timespec_to_ktime(tspec);
+
+ spin_unlock(&kvm_ptp_lock);
+
+ return 0;
+}
+
+static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
+ struct system_device_crosststamp *xtstamp)
+{
+ return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
+ NULL, xtstamp);
+}
+
+/*
+ * PTP clock operations
+ */
+
+static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_settime(struct ptp_clock_info *ptp,
+ const struct timespec64 *ts)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_enable(struct ptp_clock_info *ptp,
+ struct ptp_clock_request *rq, int on)
+{
+ return -EOPNOTSUPP;
+}
+
+static struct ptp_clock_info ptp_kvm_caps = {
+ .owner = THIS_MODULE,
+ .name = "KVM virtual PTP",
+ .max_adj = 0,
+ .n_ext_ts = 0,
+ .n_pins = 0,
+ .pps = 0,
+ .adjfreq = ptp_kvm_adjfreq,
+ .adjtime = ptp_kvm_adjtime,
+ .gettime64 = NULL,
+ .settime64 = ptp_kvm_settime,
+ .enable = ptp_kvm_enable,
+ .getcrosststamp = ptp_kvm_getcrosststamp,
+};
+
+/* module operations */
+
+static struct kvm_ptp_clock kvm_ptp_clock;
+
+static void __exit ptp_kvm_exit(void)
+{
+ ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
+}
+
+static int __init ptp_kvm_init(void)
+{
+ clock_off_gpa = slow_virt_to_phys(&clock_off);
+ hv_clock = pvclock_pvti_cpu0_va();
+
+ if (!hv_clock)
+ return -ENODEV;
+
+ kvm_ptp_clock.caps = ptp_kvm_caps;
+
+ kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
+
+ if (IS_ERR(kvm_ptp_clock.ptp_clock))
+ return PTR_ERR(kvm_ptp_clock.ptp_clock);
+
+ return 0;
+}
+
+module_init(ptp_kvm_init);
+module_exit(ptp_kvm_exit);
+
+MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
+MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
+MODULE_LICENSE("GPL");
[toc] | [prev] | [next] | [standalone]
| From | Marcelo Tosatti <mtosatti@redhat.com> |
|---|---|
| Date | 2017-01-20 16:10 +0100 |
| Subject | [patch 5/5] PTP: add kvm PTP driver (v2) |
| Message-ID | <t1IZd-oG-63@gated-at.bofh.it> |
| In reply to | #1563696 |
Add a driver with gettime method returning hosts realtime clock.
This allows Chrony to synchronize host and guest clocks with
high precision (see results below).
chronyc> sources
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
#* PHC0 0 3 377 4 +162ns[ -683ns] +/- 11ns
To configure Chronyd to use PHC refclock, add the
following line to its configuration file:
refclock PHC /dev/ptpX poll 3 dpoll -2 offset 0
Where /dev/ptpX is the kvmclock PTP clock.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
drivers/ptp/Kconfig | 12 +++
drivers/ptp/Makefile | 1
drivers/ptp/ptp_kvm.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 190 insertions(+)
v2: check for kvmclock (Radim)
initialize global variables before device registration (Radim)
v3: use cross timestamps callback (Paolo, Miroslav, Radim)
v4: remove gettime64 callback (Paolo)
v5: drop useless nsec assignment (Radim)
Index: kvm-ptpdriver/drivers/ptp/Kconfig
===================================================================
--- kvm-ptpdriver.orig/drivers/ptp/Kconfig 2017-01-20 12:48:10.221115884 -0200
+++ kvm-ptpdriver/drivers/ptp/Kconfig 2017-01-20 12:50:35.076496551 -0200
@@ -90,4 +90,16 @@
To compile this driver as a module, choose M here: the module
will be called ptp_pch.
+config PTP_1588_CLOCK_KVM
+ tristate "KVM virtual PTP clock"
+ depends on PTP_1588_CLOCK
+ depends on KVM_GUEST
+ default y
+ help
+ This driver adds support for using kvm infrastructure as a PTP
+ clock. This clock is only useful if you are using KVM guests.
+
+ To compile this driver as a module, choose M here: the module
+ will be called ptp_kvm.
+
endmenu
Index: kvm-ptpdriver/drivers/ptp/Makefile
===================================================================
--- kvm-ptpdriver.orig/drivers/ptp/Makefile 2017-01-20 12:48:10.221115884 -0200
+++ kvm-ptpdriver/drivers/ptp/Makefile 2017-01-20 12:50:35.076496551 -0200
@@ -6,3 +6,4 @@
obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o
obj-$(CONFIG_PTP_1588_CLOCK_IXP46X) += ptp_ixp46x.o
obj-$(CONFIG_PTP_1588_CLOCK_PCH) += ptp_pch.o
+obj-$(CONFIG_PTP_1588_CLOCK_KVM) += ptp_kvm.o
Index: kvm-ptpdriver/drivers/ptp/ptp_kvm.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ kvm-ptpdriver/drivers/ptp/ptp_kvm.c 2017-01-20 12:59:28.176898867 -0200
@@ -0,0 +1,177 @@
+/*
+ * Virtual PTP 1588 clock for use with KVM guests
+ *
+ * Copyright (C) 2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <uapi/linux/kvm_para.h>
+#include <asm/kvm_para.h>
+#include <asm/pvclock.h>
+#include <asm/kvmclock.h>
+#include <uapi/asm/kvm_para.h>
+
+#include <linux/ptp_clock_kernel.h>
+
+struct kvm_ptp_clock {
+ struct ptp_clock *ptp_clock;
+ struct ptp_clock_info caps;
+};
+
+DEFINE_SPINLOCK(kvm_ptp_lock);
+
+static struct pvclock_vsyscall_time_info *hv_clock;
+
+static struct kvm_clock_offset clock_off;
+static phys_addr_t clock_off_gpa;
+
+static int ptp_kvm_get_time_fn(ktime_t *device_time,
+ struct system_counterval_t *system_counter,
+ void *ctx)
+{
+ unsigned long ret;
+ struct timespec64 tspec;
+ unsigned version;
+ u8 flags;
+ int cpu;
+ struct pvclock_vcpu_time_info *src;
+
+ preempt_disable_notrace();
+ cpu = smp_processor_id();
+ src = &hv_clock[cpu].pvti;
+
+ spin_lock(&kvm_ptp_lock);
+
+ do {
+ /*
+ * We are using a TSC value read in the hosts
+ * kvm_hc_clock_pairing handling.
+ * So any changes to tsc_to_system_mul
+ * and tsc_shift or any other pvclock
+ * data invalidate that measurement.
+ */
+ version = pvclock_read_begin(src);
+
+ ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
+ clock_off_gpa,
+ KVM_CLOCK_PAIRING_WALLCLOCK);
+ if (ret != 0) {
+ pr_err("clock offset hypercall ret %lu\n", ret);
+ spin_unlock(&kvm_ptp_lock);
+ preempt_enable_notrace();
+ return -EOPNOTSUPP;
+ }
+
+ tspec.tv_sec = clock_off.sec;
+ tspec.tv_nsec = clock_off.nsec;
+ ret = __pvclock_read_cycles(src, clock_off.tsc);
+ flags = src->flags;
+ } while (pvclock_read_retry(src, version));
+
+ preempt_enable_notrace();
+
+ system_counter->cycles = ret;
+ system_counter->cs = &kvm_clock;
+
+ *device_time = timespec_to_ktime(tspec);
+
+ spin_unlock(&kvm_ptp_lock);
+
+ return 0;
+}
+
+static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
+ struct system_device_crosststamp *xtstamp)
+{
+ return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
+ NULL, xtstamp);
+}
+
+/*
+ * PTP clock operations
+ */
+
+static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_settime(struct ptp_clock_info *ptp,
+ const struct timespec64 *ts)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_enable(struct ptp_clock_info *ptp,
+ struct ptp_clock_request *rq, int on)
+{
+ return -EOPNOTSUPP;
+}
+
+static struct ptp_clock_info ptp_kvm_caps = {
+ .owner = THIS_MODULE,
+ .name = "KVM virtual PTP",
+ .max_adj = 0,
+ .n_ext_ts = 0,
+ .n_pins = 0,
+ .pps = 0,
+ .adjfreq = ptp_kvm_adjfreq,
+ .adjtime = ptp_kvm_adjtime,
+ .gettime64 = NULL,
+ .settime64 = ptp_kvm_settime,
+ .enable = ptp_kvm_enable,
+ .getcrosststamp = ptp_kvm_getcrosststamp,
+};
+
+/* module operations */
+
+static struct kvm_ptp_clock kvm_ptp_clock;
+
+static void __exit ptp_kvm_exit(void)
+{
+ ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
+}
+
+static int __init ptp_kvm_init(void)
+{
+ clock_off_gpa = slow_virt_to_phys(&clock_off);
+ hv_clock = pvclock_pvti_cpu0_va();
+
+ if (!hv_clock)
+ return -ENODEV;
+
+ kvm_ptp_clock.caps = ptp_kvm_caps;
+
+ kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
+
+ if (IS_ERR(kvm_ptp_clock.ptp_clock))
+ return PTR_ERR(kvm_ptp_clock.ptp_clock);
+
+ return 0;
+}
+
+module_init(ptp_kvm_init);
+module_exit(ptp_kvm_exit);
+
+MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
+MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
+MODULE_LICENSE("GPL");
[toc] | [prev] | [next] | [standalone]
| From | Marcelo Tosatti <mtosatti@redhat.com> |
|---|---|
| Date | 2017-01-20 16:00 +0100 |
| Subject | [patch 2/5] KVM: x86: add KVM_HC_CLOCK_OFFSET hypercall |
| Message-ID | <t1IPw-5I-23@gated-at.bofh.it> |
| In reply to | #1563695 |
Add a hypercall to retrieve the host realtime clock
and the TSC value used to calculate that clock read.
Used to implement clock synchronization between
host and guest.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
Documentation/virtual/kvm/hypercalls.txt | 33 ++++++++++++++++++++++++
arch/x86/include/uapi/asm/kvm_para.h | 9 ++++++
arch/x86/kvm/x86.c | 41 +++++++++++++++++++++++++++++++
include/uapi/linux/kvm_para.h | 3 ++
4 files changed, 86 insertions(+)
v2: improve documentation (Radim)
change hypercall name to KVM_HC_CLOCK_PAIRING (Radim)
increase padding size
Index: kvm-ptpdriver/arch/x86/include/uapi/asm/kvm_para.h
===================================================================
--- kvm-ptpdriver.orig/arch/x86/include/uapi/asm/kvm_para.h 2017-01-13 16:43:11.947240575 -0200
+++ kvm-ptpdriver/arch/x86/include/uapi/asm/kvm_para.h 2017-01-13 16:43:25.038258187 -0200
@@ -50,6 +50,15 @@
__u32 pad[11];
};
+#define KVM_CLOCK_PAIRING_WALLCLOCK 0
+struct kvm_clock_offset {
+ __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)
Index: kvm-ptpdriver/Documentation/virtual/kvm/hypercalls.txt
===================================================================
--- kvm-ptpdriver.orig/Documentation/virtual/kvm/hypercalls.txt 2017-01-13 16:43:11.947240575 -0200
+++ kvm-ptpdriver/Documentation/virtual/kvm/hypercalls.txt 2017-01-13 16:43:25.038258187 -0200
@@ -81,3 +81,36 @@
same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall,
specifying APIC ID (a1) of the vcpu to be woken up. An additional argument (a0)
is used in the hypercall for future use.
+
+
+6. KVM_HC_CLOCK_PAIRING
+------------------------
+Architecture: x86
+Status: active
+Purpose: Hypercall used to synchronize host and guest clocks.
+Usage:
+
+a0: guest physical address where host copies
+"struct kvm_clock_offset" structure.
+
+a1: clock_type, ATM only KVM_CLOCK_PAIRING_WALLCLOCK (0)
+is supported (hosts CLOCK_REALTIME clock).
+
+ struct kvm_clock_offset {
+ __s64 sec;
+ __s64 nsec;
+ __u64 tsc;
+ __u32 flags;
+ __u32 pad[9];
+ };
+
+ Where:
+ * sec: seconds from clock_type clock.
+ * nsec: nanoseconds from clock_type clock.
+ * tsc: TSC value used to calculate sec/nsec pair
+ (this hypercall only works when host uses TSC clocksource).
+ * flags: flags, unused (0) at the moment.
+
+Returns KVM_EOPNOTSUPP if the host does not use TSC clocksource,
+or if clock type is different than KVM_CLOCK_PAIRING_WALLCLOCK.
+
Index: kvm-ptpdriver/arch/x86/kvm/x86.c
===================================================================
--- kvm-ptpdriver.orig/arch/x86/kvm/x86.c 2017-01-13 16:43:20.898252596 -0200
+++ kvm-ptpdriver/arch/x86/kvm/x86.c 2017-01-13 16:43:25.041258191 -0200
@@ -6119,6 +6119,44 @@
}
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_offset *clock_offset;
+ struct timespec ts;
+ cycle_t cycle;
+ int ret;
+
+ if (clock_type != KVM_CLOCK_PAIRING_WALLCLOCK)
+ return -KVM_EOPNOTSUPP;
+
+ if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC)
+ return -KVM_EOPNOTSUPP;
+
+ clock_offset = kzalloc(sizeof(struct kvm_clock_offset), GFP_KERNEL);
+ if (clock_offset == NULL)
+ return -KVM_ENOMEM;
+
+ if (kvm_get_walltime_and_clockread(&ts, &cycle) == false) {
+ kfree(clock_offset);
+ return -KVM_EOPNOTSUPP;
+ }
+
+ clock_offset->sec = ts.tv_sec;
+ clock_offset->nsec = ts.tv_nsec;
+ clock_offset->tsc = kvm_read_l1_tsc(vcpu, cycle);
+ clock_offset->flags = 0;
+
+ ret = 0;
+ if (kvm_write_guest(vcpu->kvm, paddr, clock_offset,
+ sizeof(struct kvm_clock_offset)))
+ ret = -KVM_EFAULT;
+
+ kfree(clock_offset);
+
+ return ret;
+}
+
/*
* kvm_pv_kick_cpu_op: Kick a vcpu.
*
@@ -6183,6 +6221,9 @@
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;
Index: kvm-ptpdriver/include/uapi/linux/kvm_para.h
===================================================================
--- kvm-ptpdriver.orig/include/uapi/linux/kvm_para.h 2017-01-13 16:43:11.947240575 -0200
+++ kvm-ptpdriver/include/uapi/linux/kvm_para.h 2017-01-13 16:43:25.042258192 -0200
@@ -14,6 +14,8 @@
#define KVM_EFAULT EFAULT
#define KVM_E2BIG E2BIG
#define KVM_EPERM EPERM
+#define KVM_EOPNOTSUPP EOPNOTSUPP
+#define KVM_ENOMEM ENOMEM
#define KVM_HC_VAPIC_POLL_IRQ 1
#define KVM_HC_MMU_OP 2
@@ -23,6 +25,7 @@
#define KVM_HC_MIPS_GET_CLOCK_FREQ 6
#define KVM_HC_MIPS_EXIT_VM 7
#define KVM_HC_MIPS_CONSOLE_OUTPUT 8
+#define KVM_HC_CLOCK_PAIRING 9
/*
* hypercalls use architecture specific
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