* [patch 1/5] KVM: x86: provide realtime host clock via vsyscall notifiers
2017-01-20 12:20 [patch 0/5] KVM virtual PTP driver (v3) Marcelo Tosatti
@ 2017-01-20 12:20 ` Marcelo Tosatti
0 siblings, 0 replies; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 12:20 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar,
Marcelo Tosatti
[-- Attachment #1: kvm-do-realtime --]
[-- Type: text/plain, Size: 2012 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 | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
v2: unify nsec_base (Radim)
Index: kvm-ptpdriver/arch/x86/kvm/x86.c
===================================================================
--- kvm-ptpdriver.orig/arch/x86/kvm/x86.c 2017-01-13 16:43:15.013244682 -0200
+++ kvm-ptpdriver/arch/x86/kvm/x86.c 2017-01-20 09:56:41.404534904 -0200
@@ -1139,6 +1139,7 @@
u64 boot_ns;
u64 nsec_base;
+ u64 wall_time_sec;
};
static struct pvclock_gtod_data pvclock_gtod_data;
@@ -1162,6 +1163,8 @@
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
@@ -1623,6 +1626,28 @@
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->nsec_base;
+ 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 +1657,17 @@
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
/*
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch 0/5] KVM virtual PTP driver (v4)
@ 2017-01-20 14:51 Marcelo Tosatti
2017-01-20 14:51 ` [patch 1/5] KVM: x86: provide realtime host clock via vsyscall notifiers Marcelo Tosatti
` (4 more replies)
0 siblings, 5 replies; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 14:51 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar
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
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch 1/5] KVM: x86: provide realtime host clock via vsyscall notifiers
2017-01-20 14:51 [patch 0/5] KVM virtual PTP driver (v4) Marcelo Tosatti
@ 2017-01-20 14:51 ` Marcelo Tosatti
2017-01-20 14:51 ` [patch 2/5] KVM: x86: add KVM_HC_CLOCK_OFFSET hypercall Marcelo Tosatti
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 14:51 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar,
Marcelo Tosatti
[-- Attachment #1: kvm-do-realtime --]
[-- Type: text/plain, Size: 2010 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 | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
v2: unify nsec_base (Radim)
Index: kvm-ptpdriver/arch/x86/kvm/x86.c
===================================================================
--- kvm-ptpdriver.orig/arch/x86/kvm/x86.c 2017-01-13 16:43:15.013244682 -0200
+++ kvm-ptpdriver/arch/x86/kvm/x86.c 2017-01-20 09:56:41.404534904 -0200
@@ -1139,6 +1139,7 @@
u64 boot_ns;
u64 nsec_base;
+ u64 wall_time_sec;
};
static struct pvclock_gtod_data pvclock_gtod_data;
@@ -1162,6 +1163,8 @@
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
@@ -1623,6 +1626,28 @@
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->nsec_base;
+ 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 +1657,17 @@
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
/*
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch 2/5] KVM: x86: add KVM_HC_CLOCK_OFFSET hypercall
2017-01-20 14:51 [patch 0/5] KVM virtual PTP driver (v4) Marcelo Tosatti
2017-01-20 14:51 ` [patch 1/5] KVM: x86: provide realtime host clock via vsyscall notifiers Marcelo Tosatti
@ 2017-01-20 14:51 ` Marcelo Tosatti
2017-01-20 14:51 ` [patch 3/5] kvmclock: export kvmclock clocksource pointer Marcelo Tosatti
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 14:51 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar,
Marcelo Tosatti
[-- Attachment #1: kvm-hv-clock-offset --]
[-- Type: text/plain, Size: 5057 bytes --]
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
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch 3/5] kvmclock: export kvmclock clocksource pointer
2017-01-20 14:51 [patch 0/5] KVM virtual PTP driver (v4) Marcelo Tosatti
2017-01-20 14:51 ` [patch 1/5] KVM: x86: provide realtime host clock via vsyscall notifiers Marcelo Tosatti
2017-01-20 14:51 ` [patch 2/5] KVM: x86: add KVM_HC_CLOCK_OFFSET hypercall Marcelo Tosatti
@ 2017-01-20 14:51 ` Marcelo Tosatti
2017-01-20 14:51 ` [patch 4/5] PTP: add PTP_SYS_OFFSET emulation via cross timestamps infrastructure Marcelo Tosatti
2017-01-20 14:51 ` [patch 5/5] PTP: add kvm PTP driver Marcelo Tosatti
4 siblings, 0 replies; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 14:51 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar,
Marcelo Tosatti
[-- Attachment #1: kvmclock-export-clocksource --]
[-- Type: text/plain, Size: 1367 bytes --]
To be used by KVM PTP driver.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
arch/x86/include/asm/kvmclock.h | 6 ++++++
arch/x86/kernel/kvmclock.c | 3 ++-
2 files changed, 8 insertions(+), 1 deletion(-)
v2: export kvmclock clocksource structure directly (Paolo)
Index: kvm-ptpdriver/arch/x86/include/asm/kvmclock.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ kvm-ptpdriver/arch/x86/include/asm/kvmclock.h 2017-01-20 11:05:28.720038512 -0200
@@ -0,0 +1,6 @@
+#ifndef _ASM_X86_KVM_CLOCK_H
+#define _ASM_X86_KVM_CLOCK_H
+
+extern struct clocksource kvm_clock;
+
+#endif /* _ASM_X86_KVM_CLOCK_H */
Index: kvm-ptpdriver/arch/x86/kernel/kvmclock.c
===================================================================
--- kvm-ptpdriver.orig/arch/x86/kernel/kvmclock.c 2017-01-20 10:03:44.750489955 -0200
+++ kvm-ptpdriver/arch/x86/kernel/kvmclock.c 2017-01-20 11:05:03.137971637 -0200
@@ -28,6 +28,7 @@
#include <asm/x86_init.h>
#include <asm/reboot.h>
+#include <asm/kvmclock.h>
static int kvmclock __ro_after_init = 1;
static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME;
@@ -174,7 +175,7 @@
return ret;
}
-static struct clocksource kvm_clock = {
+struct clocksource kvm_clock = {
.name = "kvm-clock",
.read = kvm_clock_get_cycles,
.rating = 400,
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch 4/5] PTP: add PTP_SYS_OFFSET emulation via cross timestamps infrastructure
2017-01-20 14:51 [patch 0/5] KVM virtual PTP driver (v4) Marcelo Tosatti
` (2 preceding siblings ...)
2017-01-20 14:51 ` [patch 3/5] kvmclock: export kvmclock clocksource pointer Marcelo Tosatti
@ 2017-01-20 14:51 ` Marcelo Tosatti
2017-01-20 14:51 ` [patch 5/5] PTP: add kvm PTP driver Marcelo Tosatti
4 siblings, 0 replies; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 14:51 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar,
Marcelo Tosatti
[-- Attachment #1: ptp-add-sysoffset-callback --]
[-- Type: text/plain, Size: 3825 bytes --]
Emulate PTP_SYS_OFFSET by using an arithmetic mean of the
realtime samples from ->getcrosststamp callback.
Note: if the realtime clock changes during cross timestamp sampling,
then the mean will return a value that does not exist. Given the
nature of PTP_SYS_OFFSET users (time synchronization),
that should not be a problem.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
drivers/ptp/ptp_chardev.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/ptp/ptp_clock.c | 10 ++++++
2 files changed, 83 insertions(+)
v2: drop timekeeper spinlock, move back to drivers/ptp/ptp_chardev.c (Paolo)
ptp_clock_gettime: support drivers with crosstimestamp but not
gettime64 callbacks
Index: kvm-ptpdriver/drivers/ptp/ptp_chardev.c
===================================================================
--- kvm-ptpdriver.orig/drivers/ptp/ptp_chardev.c 2017-01-20 12:48:14.201126341 -0200
+++ kvm-ptpdriver/drivers/ptp/ptp_chardev.c 2017-01-20 12:48:45.270207972 -0200
@@ -116,6 +116,74 @@
return 0;
}
+static void mean_sys_realtime(struct system_device_crosststamp *xtstamp,
+ struct system_device_crosststamp *n_xtstamp,
+ struct ptp_clock_time *pct)
+{
+ ktime_t sys_realtime, n_sys_realtime;
+ struct timespec ts;
+ u64 ns;
+
+ /* estimate realtime with arithmetic mean of two crosststamp samples */
+ sys_realtime = xtstamp->sys_realtime;
+ n_sys_realtime = n_xtstamp->sys_realtime;
+ ns = ktime_divns(ktime_add(sys_realtime, n_sys_realtime), 2);
+ ts = ktime_to_timespec(ns_to_ktime(ns));
+ pct->sec = ts.tv_sec;
+ pct->nsec = ts.tv_nsec;
+}
+
+static int emulate_ptp_sys_offset(struct ptp_clock_info *info,
+ struct ptp_sys_offset *sysoff,
+ unsigned long arg)
+{
+ int i, err, len;
+ int n_samples;
+ struct system_device_crosststamp *xtstamps, *xtstamp, *n_xtstamp;
+ struct ptp_clock_time *pct;
+
+ n_samples = sysoff->n_samples + 2;
+
+ len = sizeof(struct system_device_crosststamp);
+ xtstamps = kzalloc(len * n_samples, GFP_KERNEL);
+ if (xtstamps == NULL)
+ return -ENOMEM;
+
+ xtstamp = xtstamps;
+ for (i = 0; i < n_samples; i++) {
+ err = info->getcrosststamp(info, xtstamp);
+ if (err) {
+ kfree(xtstamps);
+ return err;
+ }
+ xtstamp++;
+ }
+
+ pct = &sysoff->ts[0];
+ xtstamp = n_xtstamp = xtstamps;
+ n_xtstamp++;
+ for (i = 0; i < sysoff->n_samples; i++) {
+ struct timespec ts;
+
+ mean_sys_realtime(xtstamp, n_xtstamp, pct);
+ pct++;
+
+ ts = ktime_to_timespec(n_xtstamp->device);
+ pct->sec = ts.tv_sec;
+ pct->nsec = ts.tv_nsec;
+ pct++;
+ xtstamp++;
+ n_xtstamp++;
+ }
+
+ mean_sys_realtime(xtstamp, n_xtstamp, pct);
+ kfree(xtstamps);
+ if (copy_to_user((void __user *)arg, sysoff, sizeof(*sysoff)))
+ return -EFAULT;
+
+ return 0;
+}
+
long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
{
struct ptp_clock_caps caps;
@@ -219,6 +287,11 @@
err = -EINVAL;
break;
}
+
+ if (!ptp->info->gettime64 && ptp->info->getcrosststamp) {
+ err = emulate_ptp_sys_offset(ptp->info, sysoff, arg);
+ break;
+ }
pct = &sysoff->ts[0];
for (i = 0; i < sysoff->n_samples; i++) {
getnstimeofday64(&ts);
Index: kvm-ptpdriver/drivers/ptp/ptp_clock.c
===================================================================
--- kvm-ptpdriver.orig/drivers/ptp/ptp_clock.c 2017-01-20 12:48:14.201126341 -0200
+++ kvm-ptpdriver/drivers/ptp/ptp_clock.c 2017-01-20 12:48:45.271207975 -0200
@@ -118,6 +118,16 @@
struct timespec64 ts;
int err;
+ if (!ptp->info->gettime64 && ptp->info->getcrosststamp) {
+ struct system_device_crosststamp xtstamp;
+
+ err = ptp->info->getcrosststamp(ptp->info, &xtstamp);
+ if (err)
+ return err;
+ *tp = ktime_to_timespec(xtstamp.device);
+ return err;
+ }
+
err = ptp->info->gettime64(ptp->info, &ts);
if (!err)
*tp = timespec64_to_timespec(ts);
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch 5/5] PTP: add kvm PTP driver
2017-01-20 14:51 [patch 0/5] KVM virtual PTP driver (v4) Marcelo Tosatti
` (3 preceding siblings ...)
2017-01-20 14:51 ` [patch 4/5] PTP: add PTP_SYS_OFFSET emulation via cross timestamps infrastructure Marcelo Tosatti
@ 2017-01-20 14:51 ` Marcelo Tosatti
2017-01-20 15:03 ` [patch 5/5] PTP: add kvm PTP driver (v2) Marcelo Tosatti
4 siblings, 1 reply; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 14:51 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar,
Marcelo Tosatti
[-- Attachment #1: kvm-ptpdriver --]
[-- Type: text/plain, Size: 6844 bytes --]
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");
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch 5/5] PTP: add kvm PTP driver (v2)
2017-01-20 14:51 ` [patch 5/5] PTP: add kvm PTP driver Marcelo Tosatti
@ 2017-01-20 15:03 ` Marcelo Tosatti
0 siblings, 0 replies; 8+ messages in thread
From: Marcelo Tosatti @ 2017-01-20 15:03 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Radim Krcmar, Richard Cochran, Miroslav Lichvar
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");
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-01-20 15:03 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-01-20 14:51 [patch 0/5] KVM virtual PTP driver (v4) Marcelo Tosatti
2017-01-20 14:51 ` [patch 1/5] KVM: x86: provide realtime host clock via vsyscall notifiers Marcelo Tosatti
2017-01-20 14:51 ` [patch 2/5] KVM: x86: add KVM_HC_CLOCK_OFFSET hypercall Marcelo Tosatti
2017-01-20 14:51 ` [patch 3/5] kvmclock: export kvmclock clocksource pointer Marcelo Tosatti
2017-01-20 14:51 ` [patch 4/5] PTP: add PTP_SYS_OFFSET emulation via cross timestamps infrastructure Marcelo Tosatti
2017-01-20 14:51 ` [patch 5/5] PTP: add kvm PTP driver Marcelo Tosatti
2017-01-20 15:03 ` [patch 5/5] PTP: add kvm PTP driver (v2) Marcelo Tosatti
-- strict thread matches above, loose matches on Subject: below --
2017-01-20 12:20 [patch 0/5] KVM virtual PTP driver (v3) Marcelo Tosatti
2017-01-20 12:20 ` [patch 1/5] KVM: x86: provide realtime host clock via vsyscall notifiers Marcelo Tosatti
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