From 8fa23b6a048234f83c790a82bbcc6e23a6826b5d Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 19 Nov 2010 13:16:22 +0100 Subject: [PATCH] MCE: Fix vm86 handling for 32bit mce handler commit a129a7c84582629741e5fa6f40026efcd7a65bd4 upstream. When running on 32bit the mce handler could misinterpret vm86 mode as ring 0. This can affect whether it does recovery or not; it was possible to panic when recovery was actually possible. Fix this by always forcing vm86 to look like ring 3. Signed-off-by: Andi Kleen Signed-off-by: Tony Luck Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mcheck/mce.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 5a11ae2e9e917..dee004fea4378 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -437,6 +437,14 @@ static inline void mce_gather_info(struct mce *m, struct pt_regs *regs) if (m->mcgstatus & (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) { m->ip = regs->ip; m->cs = regs->cs; + + /* + * When in VM86 mode make the cs look like ring 3 + * always. This is a lie, but it's better than passing + * the additional vm86 bit around everywhere. + */ + if (v8086_mode(regs)) + m->cs |= 3; } /* Use accurate RIP reporting if available. */ if (rip_msr) -- 2.47.2