Thread (3 messages) 3 messages, 1 author, 2021-10-21
STALE1688d

[PATCH 1/2] x86/sev: Fix stack type check in vc_switch_off_ist()

From: Joerg Roedel <joro@8bytes.org>
Date: 2021-10-21 08:08:54
Also in: kvm, linux-coco, lkml
Subsystem: the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

From: Joerg Roedel <redacted>

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.

Reported-by: Tom Lendacky <thomas.lendacky@amd.com>
Fixes: a13644f3a53de ("x86/entry/64: Add entry code for #VC handler")
Signed-off-by: Joerg Roedel <redacted>
---
 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 a58800973aed..f516f2b4797e 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -709,7 +709,7 @@ 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:
-- 
2.33.1

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