On 6/28/24 10:54, Richard Henderson wrote:
On 6/28/24 05:42, Alex Bennée wrote:
Incorrect brace positions causes an unintended overflow on 32 bit
builds and shenanigans result.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2413
Suggested-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
---
target/i386/tcg/translate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index ad1819815a..94f13541c3 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -877,7 +877,7 @@ static CCPrepare gen_prepare_sign_nz(TCGv src, MemOp size)
return (CCPrepare) { .cond = TCG_COND_LT, .reg = src };
} else {
return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = src,
- .imm = 1ull << ((8 << size) - 1) };
+ .imm = (1ull << (8 << size)) - 1 };
This is incorrect -- we want only to test the sign bit.
Perhaps MAKE_64BIT_MASK((8 << size) - 1, 1) would make this more explicit?
I'll have a quick look at the issue and see if I can reproduce.
I can't get the cdrom test to run at all; I have no idea why.
1/1 qemu:qtest+qtest-x86_64 / qtest-x86_64/cdrom-test SKIP
0.00s
But
QTEST_QEMU_BINARY='./qemu-system-x86_64' ./tests/qtest/bios-tables-test -v -p
/x86_64/acpi/q35/mmio64
fails for me, and is resolved at 15957eb9e by reverting
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 4735f084d4..022469845e 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -1084,13 +1084,8 @@ static CCPrepare gen_prepare_eflags_z(DisasContext *s,
TCGv reg)
default:
{
MemOp size = (s->cc_op - CC_OP_ADDB) & 3;
- if (size == MO_TL) {
- return (CCPrepare) { .cond = TCG_COND_EQ, .reg = cpu_cc_dst,
- .mask = -1 };
- } else {
- return (CCPrepare) { .cond = TCG_COND_TSTEQ, .reg = cpu_cc_dst,
- .mask = -1, .imm = (1ull << (8 << size))
- 1 };
- }
+ TCGv t0 = gen_ext_tl(reg, cpu_cc_dst, size, false);
+ return (CCPrepare) { .cond = TCG_COND_EQ, .reg = t0, .mask = -1 };
}
}
}
I fought all afternoon to try and debug this, but was defeated by qtest.
I really wish we could change our tooling to simplify debugging.
r~
