From ba03584f4f88082368b2562e515c3d60421b68ce Mon Sep 17 00:00:00 2001
From: Dave Hansen <dave.hansen@linux.intel.com>
Date: Sat, 23 Jul 2016 09:50:25 +0200
Subject: [PATCH] target-i386: fix typo in xsetbv implementation
QEMU 2.6 added support for the XSAVE family of instructions, which
includes the XSETBV instruction which allows setting the XCR0
register.
But, when booting Linux kernels with XSAVE support enabled, I was
getting very early crashes where the instruction pointer was set
to 0x3. I tracked it down to a jump instruction generated by this:
gen_jmp_im(s->pc - pc_start);
where s->pc is pointing to the instruction after XSETBV and pc_start
is pointing _at_ XSETBV. Subtract the two and you get 0x3. Whoops.
The fix is to replace this typo with the pattern found everywhere
else in the file when folks want to end the translation buffer.
Richard Henderson confirmed that this is a bug and that this is the
correct fix.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: qemu-stable@nongnu.org
Cc: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target-i386/translate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/target-i386/translate.c b/target-i386/translate.c
index e81fce7bc2..fa2ac48173 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -7176,7 +7176,7 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
tcg_gen_trunc_tl_i32(cpu_tmp2_i32, cpu_regs[R_ECX]);
gen_helper_xsetbv(cpu_env, cpu_tmp2_i32, cpu_tmp1_i64);
/* End TB because translation flags may change. */
- gen_jmp_im(s->pc - pc_start);
+ gen_jmp_im(s->pc - s->cs_base);
gen_eob(s);
break;
--
2.30.2