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authorZiqiao Kong <ziqiaokong@gmail.com>2024-02-15 17:50:17 +0800
committerMichael Tokarev <mjt@tls.msk.ru>2024-02-20 18:44:21 +0300
commit0b30735d3807640587c2bc9b19ab274e0f8eef57 (patch)
tree1c6ca25440fb4e07a94ac554b03ca81c76a918d1
parentf5dddb856cccdc491547235aeafb451acd63c8b1 (diff)
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target/i386: Generate an illegal opcode exception on cmp instructions with lock prefix
target/i386: As specified by Intel Manual Vol2 3-180, cmp instructions are not allowed to have lock prefix and a `UD` should be raised. Without this patch, s1->T0 will be uninitialized and used in the case OP_CMPL. Signed-off-by: Ziqiao Kong <ziqiaokong@gmail.com> Message-ID: <20240215095015.570748-2-ziqiaokong@gmail.com> Cc: qemu-stable@nongnu.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> (cherry picked from commit 99d0dcd7f102c07a510200d768cae65e5db25d23) Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
-rw-r--r--target/i386/tcg/translate.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 8fd49ff..83c2b40 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -1480,12 +1480,13 @@ static bool check_iopl(DisasContext *s)
/* if d == OR_TMP0, it means memory operand (address in A0) */
static void gen_op(DisasContext *s1, int op, MemOp ot, int d)
{
+ /* Invalid lock prefix when destination is not memory or OP_CMPL. */
+ if ((d != OR_TMP0 || op == OP_CMPL) && s1->prefix & PREFIX_LOCK) {
+ gen_illegal_opcode(s1);
+ return;
+ }
+
if (d != OR_TMP0) {
- if (s1->prefix & PREFIX_LOCK) {
- /* Lock prefix when destination is not memory. */
- gen_illegal_opcode(s1);
- return;
- }
gen_op_mov_v_reg(s1, ot, s1->T0, d);
} else if (!(s1->prefix & PREFIX_LOCK)) {
gen_op_ld_v(s1, ot, s1->T0, s1->A0);