x86, cpufreq: Change powernow's CPB status immediately

When command to modify turbo mode (CPB on AMD processors) comes
in the actual change happens later, when P-state transition is
requested. There is no time limit on when this transition will
occur and therefore change in CPB state may take long time from
the moment when command to toggle it is issued.

This patch makes CPB mode change happen immediately when request
is made.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
Committed-by: Keir Fraser <keir@xen.org>

4 files changed, 55 insertions, 18 deletions

diff --git a/xen/arch/x86/acpi/cpufreq/powernow.c b/xen/arch/x86/acpi/cpufreq/powernow.c
index 69d7f94a1e..48b7188b8a 100644
--- a/xen/arch/x86/acpi/cpufreq/powernow.c
+++ b/xen/arch/x86/acpi/cpufreq/powernow.c
@@ -68,16 +68,37 @@ static void transition_pstate(void *drvcmd)
     struct drv_cmd *cmd;
     cmd = (struct drv_cmd *) drvcmd;
 
-    if (cmd->turbo != CPUFREQ_TURBO_UNSUPPORTED) {
+
+    wrmsrl(MSR_PSTATE_CTRL, cmd->val);
+}
+
+static void update_cpb(void *data)
+{
+    struct cpufreq_policy *policy = (struct cpufreq_policy *)data;
+
+    if (policy->turbo != CPUFREQ_TURBO_UNSUPPORTED) {
         uint64_t msr_content;
+ 
         rdmsrl(MSR_K8_HWCR, msr_content);
-        if (cmd->turbo == CPUFREQ_TURBO_ENABLED)
+
+        if (policy->turbo == CPUFREQ_TURBO_ENABLED)
             msr_content &= ~MSR_HWCR_CPBDIS_MASK;
         else
             msr_content |= MSR_HWCR_CPBDIS_MASK; 
+
         wrmsrl(MSR_K8_HWCR, msr_content);
     }
-    wrmsrl(MSR_PSTATE_CTRL, cmd->val);
+}
+
+static int powernow_cpufreq_update (int cpuid,
+				     struct cpufreq_policy *policy)
+{
+    if (!cpumask_test_cpu(cpuid, &cpu_online_map))
+        return -EINVAL;
+
+    on_selected_cpus(cpumask_of(cpuid), update_cpb, policy, 1);
+
+    return 0;
 }
 
 static int powernow_cpufreq_target(struct cpufreq_policy *policy,
@@ -300,7 +321,8 @@ static struct cpufreq_driver powernow_cpufreq_driver = {
     .verify = powernow_cpufreq_verify,
     .target = powernow_cpufreq_target,
     .init   = powernow_cpufreq_cpu_init,
-    .exit   = powernow_cpufreq_cpu_exit
+    .exit   = powernow_cpufreq_cpu_exit,
+    .update = powernow_cpufreq_update
 };
 
 unsigned int __init powernow_register_driver()
diff --git a/xen/drivers/acpi/pmstat.c b/xen/drivers/acpi/pmstat.c
index dbc1c44a61..8788f01f70 100644
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -494,13 +494,13 @@ int do_pm_op(struct xen_sysctl_pm_op *op)
 
     case XEN_SYSCTL_pm_op_enable_turbo:
     {
-        cpufreq_enable_turbo(op->cpuid);
+        ret = cpufreq_update_turbo(op->cpuid, CPUFREQ_TURBO_ENABLED);
         break;
     }
 
     case XEN_SYSCTL_pm_op_disable_turbo:
     {
-        cpufreq_disable_turbo(op->cpuid);
+        ret = cpufreq_update_turbo(op->cpuid, CPUFREQ_TURBO_DISABLED);
         break;
     }
 
diff --git a/xen/drivers/cpufreq/utility.c b/xen/drivers/cpufreq/utility.c
index fad54651b3..3dd70e2716 100644
--- a/xen/drivers/cpufreq/utility.c
+++ b/xen/drivers/cpufreq/utility.c
@@ -390,24 +390,39 @@ int cpufreq_driver_getavg(unsigned int cpu, unsigned int flag)
     return policy->cur;
 }
 
-void cpufreq_enable_turbo(int cpuid)
+int cpufreq_update_turbo(int cpuid, int new_state)
 {
     struct cpufreq_policy *policy;
+    int curr_state;
+    int ret = 0;
+
+    if (new_state != CPUFREQ_TURBO_ENABLED &&
+        new_state != CPUFREQ_TURBO_DISABLED)
+        return -EINVAL;
 
     policy = per_cpu(cpufreq_cpu_policy, cpuid);
-    if (policy && policy->turbo != CPUFREQ_TURBO_UNSUPPORTED)
-        policy->turbo = CPUFREQ_TURBO_ENABLED;
-}
+    if (!policy)
+        return -EACCES;
 
-void cpufreq_disable_turbo(int cpuid)
-{
-    struct cpufreq_policy *policy;
+    if (policy->turbo == CPUFREQ_TURBO_UNSUPPORTED)
+        return -EOPNOTSUPP;
 
-    policy = per_cpu(cpufreq_cpu_policy, cpuid);
-    if (policy && policy->turbo != CPUFREQ_TURBO_UNSUPPORTED)
-        policy->turbo = CPUFREQ_TURBO_DISABLED;
+    curr_state = policy->turbo;
+    if (curr_state == new_state)
+        return 0;
+
+    policy->turbo = new_state;
+    if (cpufreq_driver->update)
+    {
+        ret = cpufreq_driver->update(cpuid, policy);
+        if (ret)
+            policy->turbo = curr_state;
+    }
+
+    return ret;
 }
 
+
 int cpufreq_get_turbo_status(int cpuid)
 {
     struct cpufreq_policy *policy;
diff --git a/xen/include/acpi/cpufreq/cpufreq.h b/xen/include/acpi/cpufreq/cpufreq.h
index 1798b9bb19..f96c3e4ccf 100644
--- a/xen/include/acpi/cpufreq/cpufreq.h
+++ b/xen/include/acpi/cpufreq/cpufreq.h
@@ -124,8 +124,7 @@ extern int cpufreq_driver_getavg(unsigned int cpu, unsigned int flag);
 #define CPUFREQ_TURBO_UNSUPPORTED   0
 #define CPUFREQ_TURBO_ENABLED       1
 
-extern void cpufreq_enable_turbo(int cpuid);
-extern void cpufreq_disable_turbo(int cpuid);
+extern int cpufreq_update_turbo(int cpuid, int new_state);
 extern int cpufreq_get_turbo_status(int cpuid);
 
 static __inline__ int 
@@ -146,6 +145,7 @@ struct cpufreq_driver {
     char   name[CPUFREQ_NAME_LEN];
     int    (*init)(struct cpufreq_policy *policy);
     int    (*verify)(struct cpufreq_policy *policy);
+    int    (*update)(int cpuid, struct cpufreq_policy *policy);
     int    (*target)(struct cpufreq_policy *policy,
                      unsigned int target_freq,
                      unsigned int relation);