From e0a47ff4548343559136d495ece9f3fa80cacbef Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastradh@NetBSD.org>
Date: Mon, 24 Jul 2023 21:21:59 +0000
Subject: [PATCH] x86: Apply AMD's workaround for Zenbleed.

XXX pullup-8
XXX pullup-9
XXX pullup-10
---
 sys/arch/x86/include/specialreg.h |  1 +
 sys/arch/x86/x86/errata.c         | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/sys/arch/x86/include/specialreg.h b/sys/arch/x86/include/specialreg.h
index d6d7c0a4f069..3f828cf74001 100644
--- a/sys/arch/x86/include/specialreg.h
+++ b/sys/arch/x86/include/specialreg.h
@@ -1394,6 +1394,7 @@
 #define MSR_DE_CFG	0xc0011029
 #define 	DE_CFG_ERRATA_721	0x00000001
 #define 	DE_CFG_LFENCE_SERIALIZE	__BIT(1)
+#define 	DE_CFG_ERRATA_ZENBLEED	__BIT(9)
 #define 	DE_CFG_ERRATA_1021	__BIT(13)
 
 #define MSR_BU_CFG2	0xc001102a
diff --git a/sys/arch/x86/x86/errata.c b/sys/arch/x86/x86/errata.c
index d127116912eb..80885ac07c1b 100644
--- a/sys/arch/x86/x86/errata.c
+++ b/sys/arch/x86/x86/errata.c
@@ -361,6 +361,16 @@ static errata_t errata[] = {
 		1095, FALSE, MSR_LS_CFG, x86_errata_set13,
 		x86_errata_setmsr, LS_CFG_ERRATA_1095
 	},
+	/*
+	 * Zenbleed:
+	 * https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7008.html
+	 * https://github.com/google/security-research/security/advisories/GHSA-v6wh-rxpg-cmm8
+	 * https://lock.cmpxchg8b.com/zenbleed.html
+	 */
+	{
+		-1, FALSE, MSR_DE_CFG, x86_errata_set13,
+		x86_errata_setmsr, DE_CFG_ERRATA_ZENBLEED,
+	},
 };
 
 static bool