Re: [Qemu-devel] [PATCH] vhost-scsi: prevent using uninitialized vqs

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 22/10/18 4:17, yuchenlin via Qemu-devel wrote:
> Ping?
> 
> On 2018-10-12 17:07, yuchenlin@synology.com wrote:
>> From: yuchenlin <yuchenlin@synology.com>
>>
>> There are 3 virtqueues (ctrl, event and cmd) for virtio scsi device,
>> but seabios will only set the physical address for the 3rd one (cmd).
>> Then in vhost_virtqueue_start(), virtio_queue_get_desc_addr()
>> will be 0 for ctrl and event vq.
>>
>> In this case, ctrl and event vq are not initialized.
>> vhost_verify_ring_mappings may use uninitialized vhost_virtqueue
>> such that vhost_verify_ring_part_mapping returns ENOMEM.
>>
>> When encountered this problem, we got the following logs:
>>
>>     qemu-system-x86_64: Unable to map available ring for ring 0
>>     qemu-system-x86_64: Verify ring failure on region 0
>>
>> Signed-off-by: Forrest Liu <forrestl@synology.com>
>> Signed-off-by: yuchenlin <yuchenlin@synology.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

>> ---
>>  hw/scsi/vhost-scsi.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
>> index becf550085..7f21b4f9d6 100644
>> --- a/hw/scsi/vhost-scsi.c
>> +++ b/hw/scsi/vhost-scsi.c
>> @@ -183,7 +183,7 @@ static void vhost_scsi_realize(DeviceState *dev,
>> Error **errp)
>>      }
>>
>>      vsc->dev.nvqs = VHOST_SCSI_VQ_NUM_FIXED + vs->conf.num_queues;
>> -    vsc->dev.vqs = g_new(struct vhost_virtqueue, vsc->dev.nvqs);
>> +    vsc->dev.vqs = g_new0(struct vhost_virtqueue, vsc->dev.nvqs);
>>      vsc->dev.vq_index = 0;
>>      vsc->dev.backend_features = 0;
> 
>