libxl: use named options for tsc_mode.

Add an enum at the libxl level with a hopefully descriptive set of names.
Deprecate the use of an integer in xl cfg files.

Signed-off-by: Ian Campbell
Committed-by: Ian Jackson <ian.jackson.citrix.com>
Acked-by: Ian Jackson <ian.jackson.citrix.com>

diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index 3f0c4c9823d0d3363fd71852537ed76c15816676..7748922e7d6642d7782db44af3afcb8f7e1dd92e 100644 (file)
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -491,11 +491,45 @@ compatibility mode on more modern Windows OS).
 
 =item B<tsc_mode="MODE">
 
+
 Specifies how the TSC (Time Stamp Counter) should be provided to the
-guest.  XXX ???
+guest (X86 only). Specifying this option as a number is
+deprecated. Options are:
+
+=over 4
+
+=item B<"default">
+
+Guest rdtsc/p executed natively when monotonicity can be guaranteed
+and emulated otherwise (with frequency scaled if necessary).
+
+=item B<"always_emulate">
+
+Guest rdtsc/p always emulated at 1GHz (kernel and user). Guest rdtsc/p
+always emulated and the virtual TSC will appear to increment (kernel
+and user) at a fixed 1GHz rate, regardless of the PCPU HZ rate or
+power state; Although there is an overhead associated with emulation
+this will NOT affect underlying CPU performance.
+
+=item B<"native">
+
+Guest rdtsc always executed natively (no monotonicity/frequency
+guarantees); guest rdtscp emulated at native frequency if unsupported
+by h/w, else executed natively.
+
+=item B<"native_paravirt">
+
+Same as B<native>, except xen manages TSC_AUX register so guest can
+determine when a restore/migration has occurred and assumes guest
+obtains/uses pvclock-like mechanism to adjust for monotonicity and
+frequency changes.
 
 =back
 
+=back
+
+Please see F<docs/misc/tscmode.txt> for more information on this option.
+
 =head3 Support for Paravirtualisation of HVM Guests
 
 The following options allow Paravirtualised features (such as devices)

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 349eab6daba249bc050ffd23931a80870407b576..b74db341f587a79cd82436819a565493f07a1f42 100644 (file)
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -73,12 +73,29 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
               libxl_domain_build_info *info, libxl__domain_build_state *state)
 {
     libxl_ctx *ctx = libxl__gc_owner(gc);
+    int tsc_mode;
     xc_domain_max_vcpus(ctx->xch, domid, info->max_vcpus);
     xc_domain_setmaxmem(ctx->xch, domid, info->target_memkb + LIBXL_MAXMEM_CONSTANT);
     if (info->type == LIBXL_DOMAIN_TYPE_PV)
         xc_domain_set_memmap_limit(ctx->xch, domid,
                 (info->max_memkb + info->u.pv.slack_memkb));
-    xc_domain_set_tsc_info(ctx->xch, domid, info->tsc_mode, 0, 0, 0);
+    switch (info->tsc_mode) {
+    case LIBXL_TSC_MODE_DEFAULT:
+        tsc_mode = 0;
+        break;
+    case LIBXL_TSC_MODE_ALWAYS_EMULATE:
+        tsc_mode = 1;
+        break;
+    case LIBXL_TSC_MODE_NATIVE:
+        tsc_mode = 2;
+        break;
+    case LIBXL_TSC_MODE_NATIVE_PARAVIRT:
+        tsc_mode = 3;
+        break;
+    default:
+        abort();
+    }
+    xc_domain_set_tsc_info(ctx->xch, domid, tsc_mode, 0, 0, 0);
     if ( info->disable_migrate )
         xc_domain_disable_migrate(ctx->xch, domid);
 

diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 2299908cb4d544586311783ac24f51057dfcd093..dffc453c03e638404aa9dc01e30f685e2211cc10 100644 (file)
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -85,6 +85,13 @@ libxl_button = Enumeration("button", [
     (2, "SLEEP"),
     ])
 
+libxl_tsc_mode = Enumeration("tsc_mode", [
+    (0, "default"),
+    (1, "always_emulate"),
+    (2, "native"),
+    (3, "native_paravirt"),
+    ])
+
 #
 # Complex libxl types
 #
@@ -154,7 +161,7 @@ libxl_domain_create_info = Struct("domain_create_info",[
 libxl_domain_build_info = Struct("domain_build_info",[
     ("max_vcpus",       integer),
     ("cur_vcpus",       integer),
-    ("tsc_mode",        integer),
+    ("tsc_mode",        libxl_tsc_mode),
     ("max_memkb",       uint32),
     ("target_memkb",    uint32),
     ("video_memkb",     uint32),

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 5bb1080bda674f32588cfe92883d4df2531afa37..8e75c00a681e3a61f67fc774eeccd7a8fd685064 100644 (file)
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -328,7 +328,7 @@ static void printf_info(int domid,
 
     printf("\t(build_info)\n");
     printf("\t(max_vcpus %d)\n", b_info->max_vcpus);
-    printf("\t(tsc_mode %d)\n", b_info->tsc_mode);
+    printf("\t(tsc_mode %s)\n", libxl_tsc_mode_to_string(b_info->tsc_mode));
     printf("\t(max_memkb %d)\n", b_info->max_memkb);
     printf("\t(target_memkb %d)\n", b_info->target_memkb);
     printf("\t(nomigrate %d)\n", b_info->disable_migrate);
@@ -662,8 +662,28 @@ static void parse_config_data(const char *configfile_filename_report,
     if (!xlu_cfg_get_long (config, "nomigrate", &l, 0))
         b_info->disable_migrate = l;
 
-    if (!xlu_cfg_get_long(config, "tsc_mode", &l, 0))
+    if (!xlu_cfg_get_long(config, "tsc_mode", &l, 1)) {
+        const char *s = libxl_tsc_mode_to_string(l);
+        fprintf(stderr, "WARNING: specifying \"tsc_mode\" as an integer is deprecated. "
+                "Please use the named parameter variant. %s%s%s\n",
+                s ? "e.g. tsc_mode=\"" : "",
+                s ? s : "",
+                s ? "\"" : "");
+
+        if (l < LIBXL_TSC_MODE_DEFAULT ||
+            l > LIBXL_TSC_MODE_NATIVE_PARAVIRT) {
+            fprintf(stderr, "ERROR: invalid value %ld for \"tsc_mode\"\n", l);
+            exit (1);
+        }
         b_info->tsc_mode = l;
+    } else if (!xlu_cfg_get_string(config, "tsc_mode", &buf, 0)) {
+        fprintf(stderr, "got a tsc mode string: \"%s\"\n", buf);
+        if (libxl_tsc_mode_from_string(buf, &b_info->tsc_mode)) {
+            fprintf(stderr, "ERROR: invalid value \"%s\" for \"tsc_mode\"\n",
+                    buf);
+            exit (1);
+        }
+    }
 
     if (!xlu_cfg_get_long (config, "videoram", &l, 0))
         b_info->video_memkb = l * 1024;