From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:39708)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <jsnow@redhat.com>) id 1YVR79-0007lM-1J
	for qemu-devel@nongnu.org; Tue, 10 Mar 2015 16:50:55 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <jsnow@redhat.com>) id 1YVR75-0006Zt-O1
	for qemu-devel@nongnu.org; Tue, 10 Mar 2015 16:50:54 -0400
Received: from mx1.redhat.com ([209.132.183.28]:33760)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <jsnow@redhat.com>) id 1YVR75-0006Zp-Eb
	for qemu-devel@nongnu.org; Tue, 10 Mar 2015 16:50:51 -0400
Message-ID: <54FF5928.1050607@redhat.com>
Date: Tue, 10 Mar 2015 16:50:48 -0400
From: John Snow <jsnow@redhat.com>
MIME-Version: 1.0
References: <1424795655-16952-1-git-send-email-marc.mari.barcelo@gmail.com>
	<54ECBE3D.3060808@redhat.com>
In-Reply-To: <54ECBE3D.3060808@redhat.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [PATCH] libqos: Solve bug in interrupt checking
 when using MSIX in virtio-pci.c
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: stefanha@redhat.com
Cc: =?UTF-8?B?TWFyYyBNYXLDrQ==?= <marc.mari.barcelo@gmail.com>, qemu-devel@nongnu.org, afaerber@suse.de



On 02/24/2015 01:09 PM, John Snow wrote:
>
>
> On 02/24/2015 11:34 AM, Marc Mar=C3=AD wrote:
>> The MSIX interrupt was always acked without checking its value, which
>> caused a
>> race condition. If the ISR was raised between the read and the acking,
>> the ISR
>> was never detected and it timed out.
>>
>> Signed-off-by: Marc Mar=C3=AD <marc.mari.barcelo@gmail.com>
>> ---
>>   tests/libqos/virtio-pci.c |   16 ++++++++++++----
>>   1 file changed, 12 insertions(+), 4 deletions(-)
>>
>> diff --git a/tests/libqos/virtio-pci.c b/tests/libqos/virtio-pci.c
>> index 788ebaf..c74a669 100644
>> --- a/tests/libqos/virtio-pci.c
>> +++ b/tests/libqos/virtio-pci.c
>> @@ -140,8 +140,12 @@ static bool
>> qvirtio_pci_get_queue_isr_status(QVirtioDevice *d, QVirtQueue *vq)
>>               return qpci_msix_pending(dev->pdev, vqpci->msix_entry);
>>           } else {
>>               data =3D readl(vqpci->msix_addr);
>> -            writel(vqpci->msix_addr, 0);
>> -            return data =3D=3D vqpci->msix_data;
>> +            if (data =3D=3D vqpci->msix_data) {
>> +                writel(vqpci->msix_addr, 0);
>> +                return true;
>> +            } else {
>> +                return false;
>> +            }
>>           }
>>       } else {
>>           return qpci_io_readb(dev->pdev, dev->addr +
>> QVIRTIO_ISR_STATUS) & 1;
>> @@ -160,8 +164,12 @@ static bool
>> qvirtio_pci_get_config_isr_status(QVirtioDevice *d)
>>               return qpci_msix_pending(dev->pdev,
>> dev->config_msix_entry);
>>           } else {
>>               data =3D readl(dev->config_msix_addr);
>> -            writel(dev->config_msix_addr, 0);
>> -            return data =3D=3D dev->config_msix_data;
>> +            if (data =3D=3D dev->config_msix_data) {
>> +                writel(dev->config_msix_addr, 0);
>> +                return true;
>> +            } else {
>> +                return false;
>> +            }
>>           }
>>       } else {
>>           return qpci_io_readb(dev->pdev, dev->addr +
>> QVIRTIO_ISR_STATUS) & 2;
>>
>
> 1,600+ runs and no hang, thanks :)
>
> Tested-by: John Snow <jsnow@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
>

Ping?

Still hitting this failure upstream.