[Xen-devel] [PATCH 5/5] tools/libxc: allow controlling the max C-state sub-state

["Jan Beulich" <JBeulich@suse.com>]

From: Ross Lagerwall <ross.lagerwall@citrix.com>

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>

Make handling in do_pm_op() more homogeneous: Before interpreting
op->cpuid as such, handle all operations not acting on a particular
CPU. Also expose the setting via xenpm.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/tools/libxc/xc_pm.c
+++ b/tools/libxc/xc_pm.c
@@ -367,7 +367,7 @@ int xc_set_sched_opt_smt(xc_interface *x
    return rc;
 }
 
-int xc_get_cpuidle_max_cstate(xc_interface *xch, uint32_t *value)
+static int get_max_cstate(xc_interface *xch, uint32_t *value, uint32_t type)
 {
     int rc;
     DECLARE_SYSCTL;
@@ -379,7 +379,7 @@ int xc_get_cpuidle_max_cstate(xc_interfa
     }
     sysctl.cmd = XEN_SYSCTL_pm_op;
     sysctl.u.pm_op.cmd = XEN_SYSCTL_pm_op_get_max_cstate;
-    sysctl.u.pm_op.cpuid = 0;
+    sysctl.u.pm_op.cpuid = type;
     sysctl.u.pm_op.u.get_max_cstate = 0;
     rc = do_sysctl(xch, &sysctl);
     *value = sysctl.u.pm_op.u.get_max_cstate;
@@ -387,7 +387,17 @@ int xc_get_cpuidle_max_cstate(xc_interfa
     return rc;
 }
 
-int xc_set_cpuidle_max_cstate(xc_interface *xch, uint32_t value)
+int xc_get_cpuidle_max_cstate(xc_interface *xch, uint32_t *value)
+{
+    return get_max_cstate(xch, value, 0);
+}
+
+int xc_get_cpuidle_max_csubstate(xc_interface *xch, uint32_t *value)
+{
+    return get_max_cstate(xch, value, 1);
+}
+
+static int set_max_cstate(xc_interface *xch, uint32_t value, uint32_t type)
 {
     DECLARE_SYSCTL;
 
@@ -398,12 +408,22 @@ int xc_set_cpuidle_max_cstate(xc_interfa
     }
     sysctl.cmd = XEN_SYSCTL_pm_op;
     sysctl.u.pm_op.cmd = XEN_SYSCTL_pm_op_set_max_cstate;
-    sysctl.u.pm_op.cpuid = 0;
+    sysctl.u.pm_op.cpuid = type;
     sysctl.u.pm_op.u.set_max_cstate = value;
 
     return do_sysctl(xch, &sysctl);
 }
 
+int xc_set_cpuidle_max_cstate(xc_interface *xch, uint32_t value)
+{
+    return set_max_cstate(xch, value, 0);
+}
+
+int xc_set_cpuidle_max_csubstate(xc_interface *xch, uint32_t value)
+{
+    return set_max_cstate(xch, value, 1);
+}
+
 int xc_enable_turbo(xc_interface *xch, int cpuid)
 {
     DECLARE_SYSCTL;
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1906,6 +1906,9 @@ int xc_set_sched_opt_smt(xc_interface *x
 int xc_get_cpuidle_max_cstate(xc_interface *xch, uint32_t *value);
 int xc_set_cpuidle_max_cstate(xc_interface *xch, uint32_t value);
 
+int xc_get_cpuidle_max_csubstate(xc_interface *xch, uint32_t *value);
+int xc_set_cpuidle_max_csubstate(xc_interface *xch, uint32_t value);
+
 int xc_enable_turbo(xc_interface *xch, int cpuid);
 int xc_disable_turbo(xc_interface *xch, int cpuid);
 
--- a/tools/misc/xenpm.c
+++ b/tools/misc/xenpm.c
@@ -195,7 +195,15 @@ static int show_max_cstate(xc_interface
         return ret;
 
     if ( value < XEN_SYSCTL_CX_UNLIMITED )
-        printf("Max possible C-state: C%"PRIu32"\n\n", value);
+    {
+        printf("Max possible C-state: C%"PRIu32"\n", value);
+        if ( (ret = xc_get_cpuidle_max_csubstate(xc_handle, &value)) )
+            return ret;
+        if ( value < XEN_SYSCTL_CX_UNLIMITED )
+            printf("Max possible substate: %"PRIu32"\n\n", value);
+        else
+            puts("");
+    }
     else
         printf("All C-states allowed\n\n");
 
@@ -1120,13 +1128,17 @@ void get_vcpu_migration_delay_func(int a
 
 void set_max_cstate_func(int argc, char *argv[])
 {
-    int value;
+    int value, subval = XEN_SYSCTL_CX_UNLIMITED;
     char buf[12];
 
-    if ( argc != 1 ||
+    if ( argc < 1 || argc > 2 ||
          (sscanf(argv[0], "%d", &value) == 1
           ? value < 0
-          : (value = XEN_SYSCTL_CX_UNLIMITED, strcmp(argv[0], "unlimited"))) )
+          : (value = XEN_SYSCTL_CX_UNLIMITED, strcmp(argv[0], "unlimited"))) ||
+         (argc == 2 &&
+          (sscanf(argv[1], "%d", &subval) == 1
+           ? subval < 0
+           : (subval = XEN_SYSCTL_CX_UNLIMITED, strcmp(argv[1], "unlimited")))) )
     {
         fprintf(stderr, "Missing, excess, or invalid argument(s)\n");
         exit(EINVAL);
@@ -1137,8 +1149,23 @@ void set_max_cstate_func(int argc, char
     if ( !xc_set_cpuidle_max_cstate(xc_handle, (uint32_t)value) )
         printf("set max C-state to %s succeeded\n", value >= 0 ? buf : argv[0]);
     else
+    {
         fprintf(stderr, "set max C-state to %s failed (%d - %s)\n",
                 value >= 0 ? buf : argv[0], errno, strerror(errno));
+        return;
+    }
+
+    if ( value != XEN_SYSCTL_CX_UNLIMITED )
+    {
+        snprintf(buf, ARRAY_SIZE(buf), "%d", subval);
+
+        if ( !xc_set_cpuidle_max_csubstate(xc_handle, (uint32_t)subval) )
+            printf("set max C-substate to %s succeeded\n",
+                   subval >= 0 ? buf : "unlimited");
+        else
+            fprintf(stderr, "set max C-substate to %s failed (%d - %s)\n",
+                    subval >= 0 ? buf : "unlimited", errno, strerror(errno));
+    }
 }
 
 void enable_turbo_mode(int argc, char *argv[])
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -398,7 +398,40 @@ int do_pm_op(struct xen_sysctl_pm_op *op
     int ret = 0;
     const struct processor_pminfo *pmpt;
 
-    if ( !op || op->cpuid >= nr_cpu_ids || !cpu_online(op->cpuid) )
+    switch ( op->cmd )
+    {
+    case XEN_SYSCTL_pm_op_set_sched_opt_smt:
+    {
+        uint32_t saved_value = sched_smt_power_savings;
+
+        if ( op->cpuid != 0 )
+            return -EINVAL;
+        sched_smt_power_savings = !!op->u.set_sched_opt_smt;
+        op->u.set_sched_opt_smt = saved_value;
+        return 0;
+    }
+
+    case XEN_SYSCTL_pm_op_get_max_cstate:
+        BUILD_BUG_ON(XEN_SYSCTL_CX_UNLIMITED != UINT_MAX);
+        if ( op->cpuid == 0 )
+            op->u.get_max_cstate = acpi_get_cstate_limit();
+        else if ( op->cpuid == 1 )
+            op->u.get_max_cstate = acpi_get_csubstate_limit();
+        else
+            ret = -EINVAL;
+        return ret;
+
+    case XEN_SYSCTL_pm_op_set_max_cstate:
+        if ( op->cpuid == 0 )
+            acpi_set_cstate_limit(op->u.set_max_cstate);
+        else if ( op->cpuid == 1 )
+            acpi_set_csubstate_limit(op->u.set_max_cstate);
+        else
+            ret = -EINVAL;
+        return ret;
+    }
+
+    if ( op->cpuid >= nr_cpu_ids || !cpu_online(op->cpuid) )
         return -EINVAL;
     pmpt = processor_pminfo[op->cpuid];
 
@@ -438,30 +471,6 @@ int do_pm_op(struct xen_sysctl_pm_op *op
         break;
     }
 
-    case XEN_SYSCTL_pm_op_set_sched_opt_smt:
-    {
-        uint32_t saved_value;
-
-        saved_value = sched_smt_power_savings;
-        sched_smt_power_savings = !!op->u.set_sched_opt_smt;
-        op->u.set_sched_opt_smt = saved_value;
-
-        break;
-    }
-
-    case XEN_SYSCTL_pm_op_get_max_cstate:
-    {
-        BUILD_BUG_ON(XEN_SYSCTL_CX_UNLIMITED != UINT_MAX);
-        op->u.get_max_cstate = acpi_get_cstate_limit();
-        break;
-    }
-
-    case XEN_SYSCTL_pm_op_set_max_cstate:
-    {
-        acpi_set_cstate_limit(op->u.set_max_cstate);
-        break;
-    }
-
     case XEN_SYSCTL_pm_op_enable_turbo:
     {
         ret = cpufreq_update_turbo(op->cpuid, CPUFREQ_TURBO_ENABLED);
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -350,7 +350,11 @@ struct xen_sysctl_pm_op {
     /* set/reset scheduler power saving option */
     #define XEN_SYSCTL_pm_op_set_sched_opt_smt    0x21
 
-    /* cpuidle max_cstate access command */
+    /*
+     * cpuidle max C-state and max C-sub-state access command:
+     * Set cpuid to 0 for max C-state.
+     * Set cpuid to 1 for max C-sub-state.
+     */
     #define XEN_SYSCTL_pm_op_get_max_cstate       0x22
     #define XEN_SYSCTL_pm_op_set_max_cstate       0x23
 
--- a/xen/include/xen/acpi.h
+++ b/xen/include/xen/acpi.h
@@ -166,9 +166,22 @@ static inline void acpi_set_cstate_limit
 	max_cstate = new_limit;
 	return;
 }
+
+static inline unsigned int acpi_get_csubstate_limit(void)
+{
+	return max_csubstate;
+}
+
+static inline void acpi_set_csubstate_limit(unsigned int new_limit)
+{
+	max_csubstate = new_limit;
+}
+
 #else
 static inline unsigned int acpi_get_cstate_limit(void) { return 0; }
 static inline void acpi_set_cstate_limit(unsigned int new_limit) { return; }
+static inline unsigned int acpi_get_csubstate_limit(void) { return 0; }
+static inline void acpi_set_csubstate_limit(unsigned int new_limit) { return; }
 #endif
 
 #ifdef XEN_GUEST_HANDLE_PARAM




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