x86/vm86/32: Fix POPF emulation

POPF would trap if VIP was set regardless of whether IF was set.  Fix it.

Suggested-by: Stas Sergeev <stsp@list.ru>
Reported-by: Bart Oldeman <bartoldeman@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 5ed92a8ab71f ("x86/vm86: Use the normal pt_regs area for vm86")
Link: http://lkml.kernel.org/r/ce95f40556e7b2178b6bc06ee9557827ff94bd28.1521003603.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 5edb27f1a2c407ff8173161fb87cbd9130b76e8e..9d0b5af7db915c60adf23389ac47c3312dd3683a 100644 (file)
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -727,7 +727,8 @@ void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code)
        return;
 
 check_vip:
-       if (VEFLAGS & X86_EFLAGS_VIP) {
+       if ((VEFLAGS & (X86_EFLAGS_VIP | X86_EFLAGS_VIF)) ==
+           (X86_EFLAGS_VIP | X86_EFLAGS_VIF)) {
                save_v86_state(regs, VM86_STI);
                return;
        }