From 22f006eda76c2d7c6cee29ac3b151b822f6b96dd Mon Sep 17 00:00:00 2001
From: avg <avg@ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f>
Date: Tue, 17 May 2016 08:33:40 +0000
Subject: [PATCH] MFC r298736: ensure that initial local apic id is sane on AMD
 10h systems

git-svn-id: svn://svn.freebsd.org/base/stable/10@300036 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
---
 sys/amd64/amd64/initcpu.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/sys/amd64/amd64/initcpu.c b/sys/amd64/amd64/initcpu.c
index 36f2d0f02..f1d81cbef 100644
--- a/sys/amd64/amd64/initcpu.c
+++ b/sys/amd64/amd64/initcpu.c
@@ -111,6 +111,19 @@ init_amd(void)
 			wrmsr(0xc0011029, rdmsr(0xc0011029) | 1);
 		break;
 	}
+
+	/*
+	 * BIOS may fail to set InitApicIdCpuIdLo to 1 as it should per BKDG.
+	 * So, do it here or otherwise some tools could be confused by
+	 * Initial Local APIC ID reported with CPUID Function 1 in EBX.
+	 */
+	if (CPUID_TO_FAMILY(cpu_id) == 0x10) {
+		if ((cpu_feature2 & CPUID2_HV) == 0) {
+			msr = rdmsr(MSR_NB_CFG1);
+			msr |= (uint64_t)1 << 54;
+			wrmsr(MSR_NB_CFG1, msr);
+		}
+	}
 }
 
 /*
-- 
2.45.0