* [PATCH 2/3] Drivers: hv: utils: Use TimeSync samples to adjust the clock after boot.
2016-09-08 12:24 ` [PATCH 1/3] Drivers: hv: utils: Rename version definitions to reflect protocol version kys
@ 2016-09-08 12:24 ` kys
2016-09-08 12:24 ` [PATCH 3/3] Drivers: hv: utils: Support TimeSync version 4.0 protocol samples kys
1 sibling, 0 replies; 7+ messages in thread
From: kys @ 2016-09-08 12:24 UTC (permalink / raw)
To: gregkh, linux-kernel, devel, olaf, apw, vkuznets, jasowang,
leann.ogasawara, alexng
Cc: Alex Ng, K. Y. Srinivasan
From: Alex Ng <alexng@messages.microsoft.com>
Only the first 50 samples after boot were being used to discipline the
clock. After the first 50 samples, any samples from the host were ignored
and the guest clock would eventually drift from the host clock.
This patch allows TimeSync-enabled guests to continuously synchronize the
clock with the host clock, even after the first 50 samples.
Signed-off-by: Alex Ng <alexng@messages.microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
drivers/hv/hv_util.c | 20 +++++++-------------
1 files changed, 7 insertions(+), 13 deletions(-)
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index b27a8ee..4002b71 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -198,29 +198,23 @@ static void hv_set_host_time(struct work_struct *work)
* ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM.
* After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time
* message after the timesync channel is opened. Since the hv_utils module is
- * loaded after hv_vmbus, the first message is usually missed. The other
- * thing is, systime is automatically set to emulated hardware clock which may
- * not be UTC time or in the same time zone. So, to override these effects, we
- * use the first 50 time samples for initial system time setting.
+ * loaded after hv_vmbus, the first message is usually missed. This bit is
+ * considered a hard request to discipline the clock.
+ *
+ * ICTIMESYNCFLAG_SAMPLE bit indicates a time sample from host. This is
+ * typically used as a hint to the guest. The guest is under no obligation
+ * to discipline the clock.
*/
static inline void adj_guesttime(u64 hosttime, u8 flags)
{
struct adj_time_work *wrk;
- static s32 scnt = 50;
wrk = kmalloc(sizeof(struct adj_time_work), GFP_ATOMIC);
if (wrk == NULL)
return;
wrk->host_time = hosttime;
- if ((flags & ICTIMESYNCFLAG_SYNC) != 0) {
- INIT_WORK(&wrk->work, hv_set_host_time);
- schedule_work(&wrk->work);
- return;
- }
-
- if ((flags & ICTIMESYNCFLAG_SAMPLE) != 0 && scnt > 0) {
- scnt--;
+ if ((flags & (ICTIMESYNCFLAG_SYNC | ICTIMESYNCFLAG_SAMPLE)) != 0) {
INIT_WORK(&wrk->work, hv_set_host_time);
schedule_work(&wrk->work);
} else
--
1.7.4.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 3/3] Drivers: hv: utils: Support TimeSync version 4.0 protocol samples.
2016-09-08 12:24 ` [PATCH 1/3] Drivers: hv: utils: Rename version definitions to reflect protocol version kys
2016-09-08 12:24 ` [PATCH 2/3] Drivers: hv: utils: Use TimeSync samples to adjust the clock after boot kys
@ 2016-09-08 12:24 ` kys
2016-09-13 17:38 ` Olaf Hering
1 sibling, 1 reply; 7+ messages in thread
From: kys @ 2016-09-08 12:24 UTC (permalink / raw)
To: gregkh, linux-kernel, devel, olaf, apw, vkuznets, jasowang,
leann.ogasawara, alexng
Cc: Alex Ng, K. Y. Srinivasan
From: Alex Ng <alexng@messages.microsoft.com>
This enables support for more accurate TimeSync v4 samples when hosted
under Windows Server 2016 and newer hosts.
The new time samples include a "vmreferencetime" field that represents
the guest's TSC value when the host generated its time sample. This value
lets the guest calculate the latency in receiving the time sample. The
latency is added to the sample host time prior to updating the clock.
Signed-off-by: Alex Ng <alexng@messages.microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
drivers/hv/hv_util.c | 82 ++++++++++++++++++++++++++++++++++-------------
include/linux/hyperv.h | 9 +++++
2 files changed, 68 insertions(+), 23 deletions(-)
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 4002b71..6286bdc 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -37,13 +37,16 @@
#define SD_MAJOR_1 1
#define SD_VERSION_1 (SD_MAJOR_1 << 16 | SD_MINOR)
-#define TS_MAJOR 3
+#define TS_MAJOR 4
#define TS_MINOR 0
#define TS_VERSION (TS_MAJOR << 16 | TS_MINOR)
#define TS_MAJOR_1 1
#define TS_VERSION_1 (TS_MAJOR_1 << 16 | TS_MINOR)
+#define TS_MAJOR_3 3
+#define TS_VERSION_3 (TS_MAJOR_3 << 16 | TS_MINOR)
+
#define HB_MAJOR 3
#define HB_MINOR 0
#define HB_VERSION (HB_MAJOR << 16 | HB_MINOR)
@@ -161,34 +164,43 @@ static void shutdown_onchannelcallback(void *context)
}
/*
- * Set guest time to host UTC time.
- */
-static inline void do_adj_guesttime(u64 hosttime)
-{
- s64 host_tns;
- struct timespec host_ts;
-
- host_tns = (hosttime - WLTIMEDELTA) * 100;
- host_ts = ns_to_timespec(host_tns);
-
- do_settimeofday(&host_ts);
-}
-
-/*
* Set the host time in a process context.
*/
struct adj_time_work {
struct work_struct work;
u64 host_time;
+ u64 ref_time;
+ u8 flags;
};
static void hv_set_host_time(struct work_struct *work)
{
struct adj_time_work *wrk;
+ s64 host_tns;
+ u64 newtime;
+ struct timespec host_ts;
wrk = container_of(work, struct adj_time_work, work);
- do_adj_guesttime(wrk->host_time);
+
+ newtime = wrk->host_time;
+ if (ts_srv_version > TS_VERSION_3) {
+ /*
+ * Some latency has been introduced since Hyper-V generated
+ * its time sample. Take that latency into account before
+ * using TSC reference time sample from Hyper-V.
+ *
+ * This sample is given by TimeSync v4 and above hosts.
+ */
+ u64 current_tick;
+
+ rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
+ newtime += (current_tick - wrk->ref_time);
+ }
+ host_tns = (newtime - WLTIMEDELTA) * 100;
+ host_ts = ns_to_timespec(host_tns);
+
+ do_settimeofday(&host_ts);
kfree(wrk);
}
@@ -205,7 +217,7 @@ static void hv_set_host_time(struct work_struct *work)
* typically used as a hint to the guest. The guest is under no obligation
* to discipline the clock.
*/
-static inline void adj_guesttime(u64 hosttime, u8 flags)
+static inline void adj_guesttime(u64 hosttime, u64 reftime, u8 flags)
{
struct adj_time_work *wrk;
@@ -214,6 +226,8 @@ static inline void adj_guesttime(u64 hosttime, u8 flags)
return;
wrk->host_time = hosttime;
+ wrk->ref_time = reftime;
+ wrk->flags = flags;
if ((flags & (ICTIMESYNCFLAG_SYNC | ICTIMESYNCFLAG_SAMPLE)) != 0) {
INIT_WORK(&wrk->work, hv_set_host_time);
schedule_work(&wrk->work);
@@ -231,6 +245,7 @@ static void timesync_onchannelcallback(void *context)
u64 requestid;
struct icmsg_hdr *icmsghdrp;
struct ictimesync_data *timedatap;
+ struct ictimesync_ref_data *refdata;
u8 *time_txf_buf = util_timesynch.recv_buffer;
struct icmsg_negotiate *negop = NULL;
@@ -246,11 +261,27 @@ static void timesync_onchannelcallback(void *context)
time_txf_buf,
util_fw_version,
ts_srv_version);
+ pr_info("Using TimeSync version %d.%d\n",
+ ts_srv_version >> 16, ts_srv_version & 0xFFFF);
} else {
- timedatap = (struct ictimesync_data *)&time_txf_buf[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
- adj_guesttime(timedatap->parenttime, timedatap->flags);
+ if (ts_srv_version > TS_VERSION_3) {
+ refdata = (struct ictimesync_ref_data *)
+ &time_txf_buf[
+ sizeof(struct vmbuspipe_hdr) +
+ sizeof(struct icmsg_hdr)];
+
+ adj_guesttime(refdata->parenttime,
+ refdata->vmreferencetime,
+ refdata->flags);
+ } else {
+ timedatap = (struct ictimesync_data *)
+ &time_txf_buf[
+ sizeof(struct vmbuspipe_hdr) +
+ sizeof(struct icmsg_hdr)];
+ adj_guesttime(timedatap->parenttime,
+ 0,
+ timedatap->flags);
+ }
}
icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
@@ -348,12 +379,17 @@ static int util_probe(struct hv_device *dev,
ts_srv_version = TS_VERSION_1;
hb_srv_version = HB_VERSION_1;
break;
-
- default:
+ case(VERSION_WIN10):
util_fw_version = UTIL_FW_VERSION;
sd_srv_version = SD_VERSION;
ts_srv_version = TS_VERSION;
hb_srv_version = HB_VERSION;
+ break;
+ default:
+ util_fw_version = UTIL_FW_VERSION;
+ sd_srv_version = SD_VERSION;
+ ts_srv_version = TS_VERSION_3;
+ hb_srv_version = HB_VERSION;
}
ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 430619a..7d7cbff 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1423,6 +1423,15 @@ struct ictimesync_data {
u8 flags;
} __packed;
+struct ictimesync_ref_data {
+ u64 parenttime;
+ u64 vmreferencetime;
+ u8 flags;
+ char leapflags;
+ char stratum;
+ u8 reserved[3];
+} __packed;
+
struct hyperv_service_callback {
u8 msg_type;
char *log_msg;
--
1.7.4.1
^ permalink raw reply related [flat|nested] 7+ messages in thread