+/*
+ * IBS cpuid feature detection
+ */
+
+#define IBS_CPUID_FEATURES 0x8000001b
+
+/*
+ * Same bit mask as for IBS cpuid feature flags (Fn8000_001B_EAX), but
+ * bit 0 is used to indicate the existence of IBS.
+ */
+#define IBS_CAPS_AVAIL (1LL<<0)
+#define IBS_CAPS_OPCNT (1LL<<4)
+
+static u32 get_ibs_caps(void)
+{
+ u32 ibs_caps;
+ unsigned int max_level;
+
+ if (!boot_cpu_has(X86_FEATURE_IBS))
+ return 0;
+
+ /* check IBS cpuid feature flags */
+ max_level = cpuid_eax(0x80000000);
+ if (max_level < IBS_CPUID_FEATURES)
+ return IBS_CAPS_AVAIL;
+
+ ibs_caps = cpuid_eax(IBS_CPUID_FEATURES);
+ if (!(ibs_caps & IBS_CAPS_AVAIL))
+ /* cpuid flags not valid */
+ return IBS_CAPS_AVAIL;
+
+ return ibs_caps;
+}