This is the equivalent of a recent Linux change.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- a/xen/arch/x86/cpu/amd.c
+++ b/xen/arch/x86/cpu/amd.c
@@ -474,6 +474,10 @@ static void __devinit init_amd(struct cp
 	}
 #endif
 
+	/* As a rule processors have APIC timer running in deep C states */
+	if (c->x86 >= 0xf && !cpu_has_amd_erratum(c, AMD_ERRATUM_400))
+		set_bit(X86_FEATURE_ARAT, c->x86_capability);
+
 	/* Prevent TSC drift in non single-processor, single-core platforms. */
 	if ((smp_processor_id() == 1) && c1_ramping_may_cause_clock_drift(c))
 		disable_c1_ramping();
--- a/xen/include/asm-x86/amd.h
+++ b/xen/include/asm-x86/amd.h
@@ -134,6 +134,10 @@
     AMD_OSVW_ERRATUM(3, AMD_MODEL_RANGE(0x10, 0x2, 0x1, 0xff, 0xf),	\
 		        AMD_MODEL_RANGE(0x12, 0x0, 0x0, 0x1, 0x0))
 
+#define AMD_ERRATUM_400                                                 \
+    AMD_OSVW_ERRATUM(1, AMD_MODEL_RANGE(0xf, 0x41, 0x2, 0xff, 0xf),     \
+                        AMD_MODEL_RANGE(0x10, 0x2, 0x1, 0xff, 0xf))
+
 struct cpuinfo_x86;
 int cpu_has_amd_erratum(const struct cpuinfo_x86 *, int, ...);