1 files changed, 14 insertions, 0 deletions
diff --git a/sys/amd64/amd64/initcpu.c b/sys/amd64/amd64/initcpu.c
index e20a271..66e465e 100644
--- a/sys/amd64/amd64/initcpu.c
+++ b/sys/amd64/amd64/initcpu.c
@@ -139,6 +139,20 @@ init_amd(void)
 			wrmsr(0xc001102a, msr);
 		}
 	}
+
+	/*
+	 * Work around Erratum 793: Specific Combination of Writes to Write
+	 * Combined Memory Types and Locked Instructions May Cause Core Hang.
+	 * See Revision Guide for AMD Family 16h Models 00h-0Fh Processors,
+	 * revision 3.04 or later, publication 51810.
+	 */
+	if (CPUID_TO_FAMILY(cpu_id) == 0x16 && CPUID_TO_MODEL(cpu_id) <= 0xf) {
+		if ((cpu_feature2 & CPUID2_HV) == 0) {
+			msr = rdmsr(0xc0011020);
+			msr |= (uint64_t)1 << 15;
+			wrmsr(0xc0011020, msr);
+		}
+	}
 }
 
 /*