x86/cpufreq: fix turbo mode detection

{acpi,powernow}_cpufreq_cpu_init() generally don't run on the CPU the
policy they deal with is related to, hence using cpuid() directly
works only as long as all CPUs in the system are identical (which
admittedly is commonly the case).

Further add a per-policy flag indicating the availability of
APERF/MPERF MSRs, so that globally setting the .getavg accessor won't
be a problem on heterogeneous configurations.

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

1 files changed, 23 insertions, 13 deletions

diff --git a/xen/arch/x86/acpi/cpufreq/cpufreq.c b/xen/arch/x86/acpi/cpufreq/cpufreq.c
index af591ee94f..6948d7d816 100644
--- a/xen/arch/x86/acpi/cpufreq/cpufreq.c
+++ b/xen/arch/x86/acpi/cpufreq/cpufreq.c
@@ -280,7 +280,7 @@ unsigned int get_measured_perf(unsigned int cpu, unsigned int flag)
         return 0;
 
     policy = cpufreq_cpu_policy[cpu];
-    if (!policy)
+    if (!policy || !policy->aperf_mperf)
         return 0;
 
     switch (flag)
@@ -377,6 +377,26 @@ static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
     return freq;
 }
 
+static void feature_detect(void *info)
+{
+    struct cpufreq_policy *policy = info;
+    unsigned int eax, ecx;
+
+    ecx = cpuid_ecx(6);
+    if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY) {
+        policy->aperf_mperf = 1;
+        acpi_cpufreq_driver.getavg = get_measured_perf;
+    }
+
+    eax = cpuid_eax(6);
+    if (eax & 0x2) {
+        policy->turbo = CPUFREQ_TURBO_ENABLED;
+        if (cpufreq_verbose)
+            printk(XENLOG_INFO "CPU%u: Turbo Mode detected and enabled\n",
+                   smp_processor_id());
+    }
+}
+
 static unsigned int check_freqs(cpumask_t mask, unsigned int freq,
                                 struct acpi_cpufreq_data *data)
 {
@@ -615,18 +635,8 @@ acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 
     /* Check for APERF/MPERF support in hardware
      * also check for boost support */
-    if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
-        unsigned int ecx;
-        unsigned int eax;
-        ecx = cpuid_ecx(6);
-        if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY)
-            acpi_cpufreq_driver.getavg = get_measured_perf;
-        eax = cpuid_eax(6);
-        if ( eax & 0x2 ) {
-            policy->turbo = CPUFREQ_TURBO_ENABLED;
-            printk(XENLOG_INFO "Turbo Mode detected and enabled!\n");
-        }
-    }
+    if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6)
+        on_selected_cpus(cpumask_of(cpu), feature_detect, policy, 1);
 
     /*
      * the first call to ->target() should result in us actually