From: David Hildenbrand <david@redhat.com>
To: Ilya Leoshkevich <iii@linux.ibm.com>,
Richard Henderson <richard.henderson@linaro.org>,
Thomas Huth <thuth@redhat.com>
Cc: qemu-s390x@nongnu.org, qemu-devel@nongnu.org, qemu-stable@nongnu.org
Subject: Re: [PATCH 1/2] target/s390x: Use a 16-bit immediate in VREP
Date: Mon, 7 Aug 2023 19:04:00 +0200 [thread overview]
Message-ID: <f4d98473-1ddd-e45c-ba01-767bde208a77@redhat.com> (raw)
In-Reply-To: <558af8b33fa9164b0a5a21f61aa583a3776784f7.camel@linux.ibm.com>
On 07.08.23 19:02, Ilya Leoshkevich wrote:
> On Mon, 2023-08-07 at 19:00 +0200, David Hildenbrand wrote:
>> On 07.08.23 18:34, Ilya Leoshkevich wrote:
>>> Unlike most other instructions that contain an immediate element
>>> index,
>>> VREP's one is 16-bit, and not 4-bit. The code uses only 8 bits, so
>>> using, e.g., 0x101 does not lead to a specification exception.
>>>
>>> Fix by checking all 16 bits.
>>>
>>> Cc: qemu-stable@nongnu.org
>>
>> Just curious, why stable? Are there valid programs that set invalid
>> element size and they are fixed by this?
>
> None that I know of, but I thought this was still nice to have, and at
> the same time small enough to not cause any trouble.
Yes, I was just curious. From my recollection, we didn't backport all
specification exception checks.
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2023-08-07 17:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-07 16:34 [PATCH 1/2] target/s390x: Use a 16-bit immediate in VREP Ilya Leoshkevich
2023-08-07 16:34 ` [PATCH 2/2] tests/tcg/s390x: Test VREP Ilya Leoshkevich
2023-08-07 17:00 ` [PATCH 1/2] target/s390x: Use a 16-bit immediate in VREP David Hildenbrand
2023-08-07 17:02 ` Ilya Leoshkevich
2023-08-07 17:04 ` David Hildenbrand [this message]
2023-08-07 17:27 ` Michael Tokarev
2023-08-08 10:01 ` Ilya Leoshkevich
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