From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:55407)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1YSoqg-0007xb-Nt
	for qemu-devel@nongnu.org; Tue, 03 Mar 2015 10:35:11 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1YSoqa-00072q-St
	for qemu-devel@nongnu.org; Tue, 03 Mar 2015 10:35:06 -0500
Received: from mx1.redhat.com ([209.132.183.28]:53176)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1YSoqa-00072d-L4
	for qemu-devel@nongnu.org; Tue, 03 Mar 2015 10:35:00 -0500
Message-ID: <54F5D49A.6020003@redhat.com>
Date: Tue, 03 Mar 2015 16:34:50 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <1421428797-23697-1-git-send-email-fred.konrad@greensocs.com>
	<1421428797-23697-2-git-send-email-fred.konrad@greensocs.com>
	<CAFEAcA-bfQH0WmtT+msVDZV9Fk5RaZCBCR=E2tpYSCRCdFch5Q@mail.gmail.com>
	<54EF614B.1010607@greensocs.com>
	<CAFEAcA8g1HTLXdTqmq0eR-oP5=UgXp+1Yq_ze3gLO1+k0uJmDg@mail.gmail.com>
	<73E10212-3603-4B64-BA61-66607C12A16A@greensocs.com>
	<CAFEAcA8Lg_iLhd2Vs8Q1KtvWUrqRyHGjmU92RemqNmC2MDEf0w@mail.gmail.com>
	<711BBCAD-9514-4523-A456-AD4F397C41CD@greensocs.com>
	<54F5D3F4.40705@redhat.com>
	<19B4F8D2-B464-4B00-900C-A057DCCD54B3@greensocs.com>
In-Reply-To: <19B4F8D2-B464-4B00-900C-A057DCCD54B3@greensocs.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [RFC 01/10] target-arm: protect cpu_exclusive_*.
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Mark Burton <mark.burton@greensocs.com>
Cc: mttcg@greensocs.com, Peter Maydell <peter.maydell@linaro.org>, "J. Kiszka" <jan.kiszka@siemens.com>, Alexander Graf <agraf@suse.de>, QEMU Developers <qemu-devel@nongnu.org>, =?UTF-8?B?S09OUkFEIEZyw6lkw6k=?= =?UTF-8?B?cmlj?= <fred.konrad@greensocs.com>



On 03/03/2015 16:33, Mark Burton wrote:
>=20
>> On 3 Mar 2015, at 16:32, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>>
>>
>> On 03/03/2015 16:29, Mark Burton wrote:
>>>
>>> ps. on our bug - we believe somehow the STREX is being marked as
>>> failed, but actually succeeds to write something.  There are only 3
>>> ways the strex can fail: 1/ the address doesn't match - in which case
>>> no ST will be attempted 2/ the value doesn't match - which means - no
>>> ST attempted 3/ the store starts, but causes a TLB fill/exception=E2=80=
=A6
>>>
>>> The 3rd has 2 possibilities - the TLB is filled, and the store goes
>>> ahead totally normally - there should be no =E2=80=98fail=E2=80=99 - =
or an exception
>>> is generated in which case we will long jump away and never return.
>>
>> When do you release the lock?
>>
> (Thanks Paolo!)
>=20
> We release the lock in either
> a) the end of the strex
> or
> b) in the =E2=80=98raise_exception=E2=80=99

That seems right... Can you post the patch?

Paolo