linux-kernel - [tip: x86/urgent] x86/sev: Check for MWAITX and MONITORX opcodes in the #VC handler

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Message-ID: <171380514854.10875.17134181849297868311.tip-bot2@tip-bot2>
Date: Mon, 22 Apr 2024 16:59:08 -0000
From: "tip-bot2 for Tom Lendacky" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Tom Lendacky <thomas.lendacky@....com>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/sev: Check for MWAITX and MONITORX opcodes in
 the #VC handler

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     e70316d17f6ab49a6038ffd115397fd68f8c7be8
Gitweb:        https://git.kernel.org/tip/e70316d17f6ab49a6038ffd115397fd68f8c7be8
Author:        Tom Lendacky <thomas.lendacky@....com>
AuthorDate:    Mon, 22 Apr 2024 08:39:21 -05:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Mon, 22 Apr 2024 18:38:28 +02:00

x86/sev: Check for MWAITX and MONITORX opcodes in the #VC handler

The MWAITX and MONITORX instructions generate the same #VC error code as
the MWAIT and MONITOR instructions, respectively. Update the #VC handler
opcode checking to also support the MWAITX and MONITORX opcodes.

Fixes: e3ef461af35a ("x86/sev: Harden #VC instruction emulation somewhat")
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/r/453d5a7cfb4b9fe818b6fb67f93ae25468bc9e23.1713793161.git.thomas.lendacky@amd.com
---
 arch/x86/kernel/sev-shared.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 8b04958..b4f8fa0 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -1203,12 +1203,14 @@ static enum es_result vc_check_opcode_bytes(struct es_em_ctxt *ctxt,
 		break;
 
 	case SVM_EXIT_MONITOR:
-		if (opcode == 0x010f && modrm == 0xc8)
+		/* MONITOR and MONITORX instructions generate the same error code */
+		if (opcode == 0x010f && (modrm == 0xc8 || modrm == 0xfa))
 			return ES_OK;
 		break;
 
 	case SVM_EXIT_MWAIT:
-		if (opcode == 0x010f && modrm == 0xc9)
+		/* MWAIT and MWAITX instructions generate the same error code */
+		if (opcode == 0x010f && (modrm == 0xc9 || modrm == 0xfb))
 			return ES_OK;
 		break;