1 files changed, 35 insertions, 0 deletions

diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
index 396ff4cc8ed4..66d0fff1ee84 100644
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -37,4 +37,39 @@
 extern struct shared_info *HYPERVISOR_shared_info;
 extern struct start_info *xen_start_info;
 
+#include <asm/processor.h>
+
+static inline uint32_t xen_cpuid_base(void)
+{
+        uint32_t base, eax, ebx, ecx, edx;
+        char signature[13];
+
+        for (base = 0x40000000; base < 0x40010000; base += 0x100) {
+                cpuid(base, &eax, &ebx, &ecx, &edx);
+                *(uint32_t *)(signature + 0) = ebx;
+                *(uint32_t *)(signature + 4) = ecx;
+                *(uint32_t *)(signature + 8) = edx;
+                signature[12] = 0;
+
+                if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
+                        return base;
+        }
+
+        return 0;
+}
+
+#ifdef CONFIG_XEN
+extern bool xen_hvm_need_lapic(void);
+
+static inline bool xen_x2apic_para_available(void)
+{
+        return xen_hvm_need_lapic();
+}
+#else
+static inline bool xen_x2apic_para_available(void)
+{
+        return (xen_cpuid_base() != 0);
+}
+#endif
+
 #endif /* _ASM_X86_XEN_HYPERVISOR_H */