We prepare eflags for the emulated instruction, then clobber it with an 'andl'.
Fix by popping eflags as the last thing in the sequence.
Patch taken from Xen (16143:959b4b92b6bf)
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
drivers/kvm/x86_emulate.c | 30 +++++++++++++++---------------
1 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index 2e259a8..f423b0e 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -256,21 +256,21 @@ static u16 twobyte_table[256] = {
#define EFLAGS_MASK (EFLG_OF|EFLG_SF|EFLG_ZF|EFLG_AF|EFLG_PF|EFLG_CF)
/* Before executing instruction: restore necessary bits in EFLAGS. */
-#define _PRE_EFLAGS(_sav, _msk, _tmp) \
- /* EFLAGS = (_sav & _msk) | (EFLAGS & ~_msk); */ \
- "push %"_sav"; " \
- "movl %"_msk",%"_LO32 _tmp"; " \
- "andl %"_LO32 _tmp",("_STK"); " \
- "pushf; " \
- "notl %"_LO32 _tmp"; " \
- "andl %"_LO32 _tmp",("_STK"); " \
- "pop %"_tmp"; " \
- "orl %"_LO32 _tmp",("_STK"); " \
- "popf; " \
- /* _sav &= ~msk; */ \
- "movl %"_msk",%"_LO32 _tmp"; " \
- "notl %"_LO32 _tmp"; " \
- "andl %"_LO32 _tmp",%"_sav"; "
+#define _PRE_EFLAGS(_sav, _msk, _tmp) \
+ /* EFLAGS = (_sav & _msk) | (EFLAGS & ~_msk); _sav &= ~_msk; */ \
+ "movl %"_sav",%"_LO32 _tmp"; " \
+ "push %"_tmp"; " \
+ "push %"_tmp"; " \
+ "movl %"_msk",%"_LO32 _tmp"; " \
+ "andl %"_LO32 _tmp",("_STK"); " \
+ "pushf; " \
+ "notl %"_LO32 _tmp"; " \
+ "andl %"_LO32 _tmp",("_STK"); " \
+ "andl %"_LO32 _tmp","__stringify(BITS_PER_LONG/4)"("_STK"); " \
+ "pop %"_tmp"; " \
+ "orl %"_LO32 _tmp",("_STK"); " \
+ "popf; " \
+ "pop %"_sav"; "
/* After executing instruction: write-back necessary bits in EFLAGS. */
#define _POST_EFLAGS(_sav, _msk, _tmp) \
--
1.5.3.7
--
