# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1320922479 0
# Node ID bc79b560aafa1e4dc42af00e6a326dc651b5636a
# Parent 460b507e15f864dd6712f5040e36538d6e076ae4
libxl: use named options for tsc_mode.
It seems that this knob is expoerted from the hypervisor as a raw
integer (no symbolic names) documented in xen/include/asm-x86. Propagating that
all the way to the end user is hardly friendly (it's bad enough in the
hypercall interface).
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
diff -r 460b507e15f8 -r bc79b560aafa docs/user/xl-domain-config.markdown
--- a/docs/user/xl-domain-config.markdown Thu Nov 10 10:18:29 2011 +0000
+++ b/docs/user/xl-domain-config.markdown Thu Nov 10 10:54:39 2011 +0000
@@ -1,4 +1,4 @@
- # xl Domain Configuration
+# xl Domain Configuration
To create a VM (a domain in Xen terminology, sometimes called a guest)
with xl requires the provision of a domain config file. Typically
@@ -338,6 +338,29 @@ accept the defaults for these options wh
extensions (e.g. Windows XP compatibility mode on more modern
Windows OS).
+### Guest Virtual Time Controls
+
+ * `tsc_mode="MODE"`: Specifies how the TSC (Time Stamp Counter)
+ should be provided to the guest (X86 only). Specifying this option as a
number
+ is deprecated. Options are:
+
+ * `"default"`: guest rdtsc/p executed natively when monotonicity
+ can be guaranteed and emulated otherwise (with frequency scaled
+ if necessary).
+
+ * `"always_emulate"`: guest rdtsc/p always emulated at 1GHz (kernel
+ and user).
+
+ * `"native"`: guest rdtsc always executed natively (no
+ monotonicity/frequency guarantees); guest rdtscp emulated at
+ native frequency if unsupported by h/w, else executed natively.
+
+ * `"native_paravirt"`: same as `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.
+
+
### Support for Paravirtualisation of HVM Guests
The following options allow Paravirtualised features (such as devices)
@@ -546,9 +569,6 @@ certainly belong in a more appropriate s
enables certain other features which are incompatible with
migration (currently certain TSC modes XXX ?).
- * `tsc_mode=VALUE`: Specifies how the TSC (Time Stamp Counter) should
- be provided to the guest. XXX ???
-
* `pci_msitranslate=BOOLEAN`: XXX
* `pci_power_mgmt=BOOLEAN`: XXX
diff -r 460b507e15f8 -r bc79b560aafa tools/libxl/libxl_dom.c
--- a/tools/libxl/libxl_dom.c Thu Nov 10 10:18:29 2011 +0000
+++ b/tools/libxl/libxl_dom.c Thu Nov 10 10:54:39 2011 +0000
@@ -73,12 +73,29 @@ int libxl__build_pre(libxl__gc *gc, uint
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 -r 460b507e15f8 -r bc79b560aafa tools/libxl/libxl_types.idl
--- a/tools/libxl/libxl_types.idl Thu Nov 10 10:18:29 2011 +0000
+++ b/tools/libxl/libxl_types.idl Thu Nov 10 10:54:39 2011 +0000
@@ -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("domai
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 -r 460b507e15f8 -r bc79b560aafa tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c Thu Nov 10 10:18:29 2011 +0000
+++ b/tools/libxl/xl_cmdimpl.c Thu Nov 10 10:54:39 2011 +0000
@@ -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 +662,23 @@ static void parse_config_data(const char
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)) {
+ fprintf(stderr, "WARNING: specifying \"tsc_mode\" as an integer is
deprecated. "
+ "Please use the named parameter variant.\n");
+ 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;
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