[PATCH 0/2] tools: add wallclock synchronization

[PATCH 0/2] tools: add wallclock synchronization

[David Vrabel]

This is the toolstack side of the Linux wallclock fixes.  A new libxc
call, xc_wallclock_sync() is provided and a new command line utility
(xen-wallclock) makes use of this.

I also considered making libxl call xc_wallclock_sync() during domain
creation but wasn't sure if this was sensible or whether there needed
to be an xl configuration option to enable/disable this behaviour.
Any comments?

David

[PATCH 1/2] libxc: add xc_wallclock_sync()

[David Vrabel]

From: David Vrabel <david.vrabel@citrix.com>

xc_wallclock_sync() synchronizes the Xen wallclock to system time.

This requires a Linux kernel with a privcmd device that provides the
IOCTL_PRIVCMD_SYNC_WALLCLOCK ioctl.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 tools/include/xen-sys/Linux/privcmd.h |    8 ++++++++
 tools/libxc/Makefile                  |    1 +
 tools/libxc/xc_linux_osdep.c          |    7 +++++++
 tools/libxc/xc_wallclock.c            |   23 +++++++++++++++++++++++
 tools/libxc/xenctrl.h                 |    5 +++++
 tools/libxc/xenctrlosdep.h            |    2 ++
 6 files changed, 46 insertions(+), 0 deletions(-)
 create mode 100644 tools/libxc/xc_wallclock.c

diff --git a/tools/include/xen-sys/Linux/privcmd.h b/tools/include/xen-sys/Linux/privcmd.h
index d35aac9..55765d1 100644
--- a/tools/include/xen-sys/Linux/privcmd.h
+++ b/tools/include/xen-sys/Linux/privcmd.h
@@ -76,6 +76,12 @@ typedef struct privcmd_mmapbatch_v2 {
  * @cmd: IOCTL_PRIVCMD_HYPERCALL
  * @arg: &privcmd_hypercall_t
  * Return: Value returned from execution of the specified hypercall.
+ *
+ * @cmd: IOCTL_PRIVCMD_SYNC_WALLCLOCK
+ * @arg: Unused.
+ * Synchronizes the Xen wallclock with the current system time.
+ * Return: 0 on success, or -1 on error with errno set to EPERM or
+ * EACCES.
  */
 #define IOCTL_PRIVCMD_HYPERCALL					\
 	_IOC(_IOC_NONE, 'P', 0, sizeof(privcmd_hypercall_t))
@@ -85,5 +91,7 @@ typedef struct privcmd_mmapbatch_v2 {
 	_IOC(_IOC_NONE, 'P', 3, sizeof(privcmd_mmapbatch_t))
 #define IOCTL_PRIVCMD_MMAPBATCH_V2				\
 	_IOC(_IOC_NONE, 'P', 4, sizeof(privcmd_mmapbatch_v2_t))
+#define IOCTL_PRIVCMD_SYNC_WALLCLOCK				\
+	_IOC(_IOC_NONE, 'P', 5, 0)
 
 #endif /* __LINUX_PUBLIC_PRIVCMD_H__ */
diff --git a/tools/libxc/Makefile b/tools/libxc/Makefile
index d44abf9..601ea4b 100644
--- a/tools/libxc/Makefile
+++ b/tools/libxc/Makefile
@@ -31,6 +31,7 @@ CTRL_SRCS-y       += xc_mem_access.c
 CTRL_SRCS-y       += xc_memshr.c
 CTRL_SRCS-y       += xc_hcall_buf.c
 CTRL_SRCS-y       += xc_foreign_memory.c
+CTRL_SRCS-y       += xc_wallclock.c
 CTRL_SRCS-y       += xtl_core.c
 CTRL_SRCS-y       += xtl_logger_stdio.c
 CTRL_SRCS-$(CONFIG_X86) += xc_pagetab.c
diff --git a/tools/libxc/xc_linux_osdep.c b/tools/libxc/xc_linux_osdep.c
index 787e742..7c73b66 100644
--- a/tools/libxc/xc_linux_osdep.c
+++ b/tools/libxc/xc_linux_osdep.c
@@ -412,6 +412,11 @@ static void *linux_privcmd_map_foreign_ranges(xc_interface *xch, xc_osdep_handle
     return ret;
 }
 
+static int linux_wallclock_sync(xc_interface *xch, xc_osdep_handle h)
+{
+    return ioctl(h, IOCTL_PRIVCMD_SYNC_WALLCLOCK, NULL);
+}
+
 static struct xc_osdep_ops linux_privcmd_ops = {
     .open = &linux_privcmd_open,
     .close = &linux_privcmd_close,
@@ -426,6 +431,8 @@ static struct xc_osdep_ops linux_privcmd_ops = {
         .map_foreign_bulk = &linux_privcmd_map_foreign_bulk,
         .map_foreign_range = &linux_privcmd_map_foreign_range,
         .map_foreign_ranges = &linux_privcmd_map_foreign_ranges,
+
+        .wallclock_sync = linux_wallclock_sync,
     },
 };
 
diff --git a/tools/libxc/xc_wallclock.c b/tools/libxc/xc_wallclock.c
new file mode 100644
index 0000000..5119b2a
--- /dev/null
+++ b/tools/libxc/xc_wallclock.c
@@ -0,0 +1,23 @@
+/******************************************************************************
+ * xc_wallclock.c
+ *
+ * API for the wallclock.
+ *
+ * Copyright (C) 2012, Citrix Systems (UK) Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ */
+
+#include "xc_private.h"
+
+int xc_wallclock_sync(xc_interface *xch)
+{
+    if (xch->ops->u.privcmd.wallclock_sync == NULL) {
+        errno = ENOSYS;
+        return -1;
+    }
+    return xch->ops->u.privcmd.wallclock_sync(xch, xch->ops_handle);
+}
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 7eb5743..f9bb21b 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -2224,4 +2224,9 @@ int xc_compression_uncompress_page(xc_interface *xch, char *compbuf,
 				   unsigned long compbuf_size,
 				   unsigned long *compbuf_pos, char *dest);
 
+/**
+ * Synchronize Xen's wallclock with the current system time.
+ */
+int xc_wallclock_sync(xc_interface *xch);
+
 #endif /* XENCTRL_H */
diff --git a/tools/libxc/xenctrlosdep.h b/tools/libxc/xenctrlosdep.h
index a36c4aa..3aa3360 100644
--- a/tools/libxc/xenctrlosdep.h
+++ b/tools/libxc/xenctrlosdep.h
@@ -89,6 +89,8 @@ struct xc_osdep_ops
             void *(*map_foreign_ranges)(xc_interface *xch, xc_osdep_handle h, uint32_t dom, size_t size, int prot,
                                         size_t chunksize, privcmd_mmap_entry_t entries[],
                                         int nentries);
+
+            int (*wallclock_sync)(xc_interface *xch, xc_osdep_handle h);
         } privcmd;
         struct {
             int (*fd)(xc_evtchn *xce, xc_osdep_handle h);
-- 
1.7.2.5

[PATCH 2/2] tools/misc: add xen-wallclock command

[David Vrabel]

From: David Vrabel <david.vrabel@citrix.com>

Add the xen-wallclock command for synchronizing the Xen wallclock to
system time.  The command is similar to the hwclock command for
synchronizing the hardware RTC and takes a similar --systowc command
line option.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 .gitignore                 |    1 +
 .hgignore                  |    1 +
 tools/misc/Makefile        |    8 +++-
 tools/misc/xen-wallclock.c |   87 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 95 insertions(+), 2 deletions(-)
 create mode 100644 tools/misc/xen-wallclock.c

diff --git a/.gitignore b/.gitignore
index f6edc43..a62abd2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -196,6 +196,7 @@ tools/misc/xc_shadow
 tools/misc/xen_cpuperf
 tools/misc/xen-detect
 tools/misc/xen-tmem-list-parse
+tools/misc/xen-wallclock
 tools/misc/xenperf
 tools/misc/xenpm
 tools/misc/xen-hvmctx
diff --git a/.hgignore b/.hgignore
index 344792a..3b6f747 100644
--- a/.hgignore
+++ b/.hgignore
@@ -198,6 +198,7 @@
 ^tools/misc/xen-hptool$
 ^tools/misc/xen-hvmcrash$
 ^tools/misc/xen-tmem-list-parse$
+^tools/misc/xen-wallclock$
 ^tools/misc/xenperf$
 ^tools/misc/xenpm$
 ^tools/misc/xen-hvmctx$
diff --git a/tools/misc/Makefile b/tools/misc/Makefile
index 22e60fd..456d1ad 100644
--- a/tools/misc/Makefile
+++ b/tools/misc/Makefile
@@ -9,7 +9,8 @@ CFLAGS += $(CFLAGS_libxenstore)
 
 HDRS     = $(wildcard *.h)
 
-TARGETS-y := xenperf xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd
+TARGETS-y := xenperf xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd \
+	xen-wallclock
 TARGETS-$(CONFIG_X86) += xen-detect xen-hvmctx xen-hvmcrash xen-lowmemd
 TARGETS-$(CONFIG_MIGRATE) += xen-hptool
 TARGETS := $(TARGETS-y)
@@ -22,7 +23,7 @@ INSTALL_BIN-y := xencons
 INSTALL_BIN-$(CONFIG_X86) += xen-detect
 INSTALL_BIN := $(INSTALL_BIN-y)
 
-INSTALL_SBIN-y := xm xen-bugtool xen-python-path xend xenperf xsview xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd xen-ringwatch
+INSTALL_SBIN-y := xm xen-bugtool xen-python-path xend xenperf xsview xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd xen-ringwatch xen-wallclock
 INSTALL_SBIN-$(CONFIG_X86) += xen-hvmctx xen-hvmcrash xen-lowmemd
 INSTALL_SBIN-$(CONFIG_MIGRATE) += xen-hptool
 INSTALL_SBIN := $(INSTALL_SBIN-y)
@@ -85,4 +86,7 @@ xen-lowmemd: xen-lowmemd.o
 gtraceview: gtraceview.o
 	$(CC) $(LDFLAGS) -o $@ $< $(CURSES_LIBS) $(APPEND_LDFLAGS)
 
+xen-wallclock: xen-wallclock.o
+	$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
+
 -include $(DEPS)
diff --git a/tools/misc/xen-wallclock.c b/tools/misc/xen-wallclock.c
new file mode 100644
index 0000000..e4af166
--- /dev/null
+++ b/tools/misc/xen-wallclock.c
@@ -0,0 +1,87 @@
+/*
+ * xen-wallclock.c: manage the Xen wallclock.
+ * Copyright (C) 2012, Citrix Systems (UK) Ltd.
+ *
+ * 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.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <getopt.h>
+
+#include <xenctrl.h>
+
+static const char *exe_name;
+
+static void usage(FILE *f)
+{
+    fprintf(f, "Usage: %s --systowc\n", exe_name);
+}
+
+static void help(void)
+{
+    usage(stdout);
+    printf("Synchronize the Xen wallclock with system time.\n"
+           "\n"
+           "  -w, --systowc synchronize wallclock with system time\n"
+           "      --help    display this help and exit\n");
+    exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+    const static char sopts[] = "w";
+    const static struct option lopts[] = {
+        { "help", 0, NULL, 0 },
+        { "systowc", 0, NULL, 'w' },
+        { 0, 0, NULL, 0 },
+    };
+    int opt, opt_idx;
+
+    int systowc = 0;
+    xc_interface *xch;
+
+    exe_name = argv[0];
+
+    while ( (opt = getopt_long(argc, argv, sopts, lopts, &opt_idx)) != -1 )
+    {
+        switch ( opt )
+        {
+        case 'w':
+            systowc = 1;
+            break;
+        case 0:
+            switch (opt_idx)
+            {
+            case 0:
+                help();
+            }
+            break;
+        default:
+            usage(stderr);
+            exit(1);
+        }
+    }
+
+    /* Valid combination of options? i.e., --systowc */
+    if (!systowc)
+    {
+        usage(stderr);
+        exit(1);
+    }
+
+    xch = xc_interface_open(NULL, NULL, 0);
+    if (xch == NULL)
+    {
+        exit(1);
+    }
+    xc_wallclock_sync(xch);
+    xc_interface_close(xch);
+
+    return 0;
+}
-- 
1.7.2.5

Re: [PATCH 2/2] tools/misc: add xen-wallclock command

[Ian Campbell]

On Fri, 2012-10-12 at 14:02 +0100, David Vrabel wrote:
> +int main(int argc, char *argv[])
> +{
> +    const static char sopts[] = "w";
> +    const static struct option lopts[] = {
> +        { "help", 0, NULL, 0 },
> +        { "systowc", 0, NULL, 'w' },
> +        { 0, 0, NULL, 0 },
> +    };
> +    int opt, opt_idx;
> +
> +    int systowc = 0;
> +    xc_interface *xch;
> +
> +    exe_name = argv[0];
> +
> +    while ( (opt = getopt_long(argc, argv, sopts, lopts, &opt_idx)) != -1 )
> +    {
> +        switch ( opt )
> +        {
> +        case 'w':
> +            systowc = 1;
> +            break;
> +        case 0:
> +            switch (opt_idx)
> +            {
> +            case 0:
> +                help();
> +            }
> +            break;
> +        default:
> +            usage(stderr);
> +            exit(1);
> +        }
> +    }
> +
> +    /* Valid combination of options? i.e., --systowc */
> +    if (!systowc)
> +    {
> +        usage(stderr);
> +        exit(1);
> +    }
> +
> +    xch = xc_interface_open(NULL, NULL, 0);
> +    if (xch == NULL)
> +    {

I forget: Does xc_interface_open log on error?

> +        exit(1);
> +    }
> +    xc_wallclock_sync(xch);

Worth logging if this fails?

I suppose we want to hold off on this and the first patch until the
Linux side is agreed and committed?

> +    xc_interface_close(xch);
> +
> +    return 0;
> +}

Re: [PATCH 2/2] tools/misc: add xen-wallclock command

[David Vrabel]

On 15/10/12 10:35, Ian Campbell wrote:
> On Fri, 2012-10-12 at 14:02 +0100, David Vrabel wrote:
>> +int main(int argc, char *argv[])
>> +{
>> +    const static char sopts[] = "w";
>> +    const static struct option lopts[] = {
>> +        { "help", 0, NULL, 0 },
>> +        { "systowc", 0, NULL, 'w' },
>> +        { 0, 0, NULL, 0 },
>> +    };
>> +    int opt, opt_idx;
>> +
>> +    int systowc = 0;
>> +    xc_interface *xch;
>> +
>> +    exe_name = argv[0];
>> +
>> +    while ( (opt = getopt_long(argc, argv, sopts, lopts, &opt_idx)) != -1 )
>> +    {
>> +        switch ( opt )
>> +        {
>> +        case 'w':
>> +            systowc = 1;
>> +            break;
>> +        case 0:
>> +            switch (opt_idx)
>> +            {
>> +            case 0:
>> +                help();
>> +            }
>> +            break;
>> +        default:
>> +            usage(stderr);
>> +            exit(1);
>> +        }
>> +    }
>> +
>> +    /* Valid combination of options? i.e., --systowc */
>> +    if (!systowc)
>> +    {
>> +        usage(stderr);
>> +        exit(1);
>> +    }
>> +
>> +    xch = xc_interface_open(NULL, NULL, 0);
>> +    if (xch == NULL)
>> +    {
> 
> I forget: Does xc_interface_open log on error?

Yes.

>> +        exit(1);
>> +    }
>> +    xc_wallclock_sync(xch);
> 
> Worth logging if this fails?

Yes.

> I suppose we want to hold off on this and the first patch until the
> Linux side is agreed and committed?

Yes.

>> +    xc_interface_close(xch);
>> +
>> +    return 0;
>> +}

David