From 958d4b4dce1f2efe99ea12e57d7fb93314505631 Mon Sep 17 00:00:00 2001

From: Joerg Roedel <jroedel@suse.de>

Date: Thu, 21 Oct 2021 10:08:32 +0200

Subject: [PATCH] x86/sev: Fix stack type check in vc_switch_off_ist()

Git-commit: 5681981fb788281b09a4ea14d310d30b2bd89132

Patch-mainline: v5.16-rc1

References: stable-5.14.19

[ Upstream commit 5681981fb788281b09a4ea14d310d30b2bd89132 ]

The value of STACK_TYPE_EXCEPTION_LAST points to the last _valid_

exception stack. Reflect that in the check done in the

vc_switch_off_ist() function.

Fixes: a13644f3a53de ("x86/entry/64: Add entry code for #VC handler")

Reported-by: Tom Lendacky <thomas.lendacky@amd.com>

Signed-off-by: Joerg Roedel <jroedel@suse.de>

Signed-off-by: Borislav Petkov <bp@suse.de>

Link: https://lkml.kernel.org/r/20211021080833.30875-2-joro@8bytes.org

Signed-off-by: Sasha Levin <sashal@kernel.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 arch/x86/kernel/traps.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c

index cc6de3a01293..5b1984d46822 100644

--- a/arch/x86/kernel/traps.c

+++ b/arch/x86/kernel/traps.c

@@ -743,7 +743,7 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r

 	stack = (unsigned long *)sp;

 	if (!get_stack_info_noinstr(stack, current, &info) || info.type == STACK_TYPE_ENTRY ||

-	    info.type >= STACK_TYPE_EXCEPTION_LAST)

+	    info.type > STACK_TYPE_EXCEPTION_LAST)

 		sp = __this_cpu_ist_top_va(VC2);

 sync:

-- 

2.26.2