Re: [Qemu-devel] [PATCH] libqos: Solve bug in interrupt checking when using MSIX in virtio-pci.c

[John Snow <jsnow@redhat.com>]

On 02/24/2015 01:09 PM, John Snow wrote:
>
>
> On 02/24/2015 11:34 AM, Marc Marí 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 Marí <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 = readl(vqpci->msix_addr);
>> -            writel(vqpci->msix_addr, 0);
>> -            return data == vqpci->msix_data;
>> +            if (data == 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 = readl(dev->config_msix_addr);
>> -            writel(dev->config_msix_addr, 0);
>> -            return data == dev->config_msix_data;
>> +            if (data == 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.