diff mbox series

[v4,04/19] vhost: fix payload size of reply

Message ID 20181008152557.14275-5-maxime.coquelin@redhat.com (mailing list archive)
State Superseded, archived
Delegated to: Maxime Coquelin
Headers
Series vhost: add postcopy live-migration support |

Checks

Context Check Description
ci/Intel-compilation success Compilation OK

Commit Message

Maxime Coquelin Oct. 8, 2018, 3:25 p.m. UTC 
  QEMU doesn't expect any payload for the reply of
VHOST_USER_SET_LOG_BASE request, so don't send any.
Note that the Vhost-user specification isn't clear about
it and would need to be fixed.

Fixes: 54f9e32305d4 ("vhost: handle dirty pages logging request")
Cc: stable@dpdk.org

Reported-by: Ilya Maximets <i.maximets@samsung.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Ilya Maximets <i.maximets@samsung.com>
---
 lib/librte_vhost/vhost_user.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Tiwei Bie Oct. 9, 2018, 10:21 a.m. UTC | #1 
On Mon, Oct 08, 2018 at 05:25:42PM +0200, Maxime Coquelin wrote:
> QEMU doesn't expect any payload for the reply of
> VHOST_USER_SET_LOG_BASE request, so don't send any.
> Note that the Vhost-user specification isn't clear about
> it and would need to be fixed.
> 
> Fixes: 54f9e32305d4 ("vhost: handle dirty pages logging request")
> Cc: stable@dpdk.org
> 
> Reported-by: Ilya Maximets <i.maximets@samsung.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> Acked-by: Ilya Maximets <i.maximets@samsung.com>
> ---
>  lib/librte_vhost/vhost_user.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 7f3e86778..71a0e7dd7 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -1296,7 +1296,11 @@ vhost_user_set_log_base(struct virtio_net **pdev, struct VhostUserMsg *msg)
>  	dev->log_base = dev->log_addr + off;
>  	dev->log_size = size;
>  
> -	msg->size = sizeof(msg->payload.u64);
> +	/*
> +	 * The spec is not clear about it (yet), but QEMU doesn't expect
> +	 * any payload in the reply.
> +	 */
> +	msg->size = 0;

I think the spec is clear about it that no payload is
expected in the reply:

https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L496

But below line in the spec needs to be fixed:

https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L495


>  
>  	return VH_RESULT_REPLY;
>  }
> -- 
> 2.17.1
>
Maxime Coquelin Oct. 9, 2018, 10:30 a.m. UTC | #2 
On 10/09/2018 12:21 PM, Tiwei Bie wrote:
> On Mon, Oct 08, 2018 at 05:25:42PM +0200, Maxime Coquelin wrote:
>> QEMU doesn't expect any payload for the reply of
>> VHOST_USER_SET_LOG_BASE request, so don't send any.
>> Note that the Vhost-user specification isn't clear about
>> it and would need to be fixed.
>>
>> Fixes: 54f9e32305d4 ("vhost: handle dirty pages logging request")
>> Cc: stable@dpdk.org
>>
>> Reported-by: Ilya Maximets <i.maximets@samsung.com>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Acked-by: Ilya Maximets <i.maximets@samsung.com>
>> ---
>>   lib/librte_vhost/vhost_user.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>> index 7f3e86778..71a0e7dd7 100644
>> --- a/lib/librte_vhost/vhost_user.c
>> +++ b/lib/librte_vhost/vhost_user.c
>> @@ -1296,7 +1296,11 @@ vhost_user_set_log_base(struct virtio_net **pdev, struct VhostUserMsg *msg)
>>   	dev->log_base = dev->log_addr + off;
>>   	dev->log_size = size;
>>   
>> -	msg->size = sizeof(msg->payload.u64);
>> +	/*
>> +	 * The spec is not clear about it (yet), but QEMU doesn't expect
>> +	 * any payload in the reply.
>> +	 */
>> +	msg->size = 0;
> 
> I think the spec is clear about it that no payload is
> expected in the reply:
> 
> https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L496
It isn't really clear because there are two cases[0]:
1. VHOST_USER_PROTOCOL_F_LOG_SHMFD not negotiated: In this case no reply
    has to be sent.
2. VHOST_USER_PROTOCOL_F_LOG_SHMFD negotiated: In this case reply with
    empty payload hsa to be sent.

[0]: 
https://github.com/qemu/qemu/blob/7c69b7c849641a39ba3defa40d384a2ba24cd7a2/docs/interop/vhost-user.txt#L177

> But below line in the spec needs to be fixed:
> 
> https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L495

Indeed.

> 
>>   
>>   	return VH_RESULT_REPLY;
>>   }
>> -- 
>> 2.17.1
>>
Maxime Coquelin Oct. 9, 2018, 10:34 a.m. UTC | #3 
On 10/09/2018 12:30 PM, Maxime Coquelin wrote:
> 
> 
> On 10/09/2018 12:21 PM, Tiwei Bie wrote:
>> On Mon, Oct 08, 2018 at 05:25:42PM +0200, Maxime Coquelin wrote:
>>> QEMU doesn't expect any payload for the reply of
>>> VHOST_USER_SET_LOG_BASE request, so don't send any.
>>> Note that the Vhost-user specification isn't clear about
>>> it and would need to be fixed.
>>>
>>> Fixes: 54f9e32305d4 ("vhost: handle dirty pages logging request")
>>> Cc: stable@dpdk.org
>>>
>>> Reported-by: Ilya Maximets <i.maximets@samsung.com>
>>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>>> Acked-by: Ilya Maximets <i.maximets@samsung.com>
>>> ---
>>>   lib/librte_vhost/vhost_user.c | 6 +++++-
>>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/librte_vhost/vhost_user.c 
>>> b/lib/librte_vhost/vhost_user.c
>>> index 7f3e86778..71a0e7dd7 100644
>>> --- a/lib/librte_vhost/vhost_user.c
>>> +++ b/lib/librte_vhost/vhost_user.c
>>> @@ -1296,7 +1296,11 @@ vhost_user_set_log_base(struct virtio_net 
>>> **pdev, struct VhostUserMsg *msg)
>>>       dev->log_base = dev->log_addr + off;
>>>       dev->log_size = size;
>>> -    msg->size = sizeof(msg->payload.u64);
>>> +    /*
>>> +     * The spec is not clear about it (yet), but QEMU doesn't expect
>>> +     * any payload in the reply.
>>> +     */
>>> +    msg->size = 0;
>>
>> I think the spec is clear about it that no payload is
>> expected in the reply:
>>
>> https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L496 
>>
> It isn't really clear because there are two cases[0]:
> 1. VHOST_USER_PROTOCOL_F_LOG_SHMFD not negotiated: In this case no reply
>     has to be sent.
> 2. VHOST_USER_PROTOCOL_F_LOG_SHMFD negotiated: In this case reply with
>     empty payload hsa to be sent.
> 
> [0]: 
> https://github.com/qemu/qemu/blob/7c69b7c849641a39ba3defa40d384a2ba24cd7a2/docs/interop/vhost-user.txt#L177 
> 

And I would add that N/A isn't clear, because SET_VRING_ADDR specifies
N/A as slave payload, whereas the implementation does not implement a
reply.

>> But below line in the spec needs to be fixed:
>>
>> https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L495 
>>
> 
> Indeed.
> 
>>
>>>       return VH_RESULT_REPLY;
>>>   }
>>> -- 
>>> 2.17.1
>>>
Tiwei Bie Oct. 9, 2018, 11:02 a.m. UTC | #4 
On Tue, Oct 09, 2018 at 12:34:28PM +0200, Maxime Coquelin wrote:
> On 10/09/2018 12:30 PM, Maxime Coquelin wrote:
> > On 10/09/2018 12:21 PM, Tiwei Bie wrote:
> > > On Mon, Oct 08, 2018 at 05:25:42PM +0200, Maxime Coquelin wrote:
> > > > QEMU doesn't expect any payload for the reply of
> > > > VHOST_USER_SET_LOG_BASE request, so don't send any.
> > > > Note that the Vhost-user specification isn't clear about
> > > > it and would need to be fixed.
> > > > 
> > > > Fixes: 54f9e32305d4 ("vhost: handle dirty pages logging request")
> > > > Cc: stable@dpdk.org
> > > > 
> > > > Reported-by: Ilya Maximets <i.maximets@samsung.com>
> > > > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> > > > Acked-by: Ilya Maximets <i.maximets@samsung.com>
> > > > ---
> > > >   lib/librte_vhost/vhost_user.c | 6 +++++-
> > > >   1 file changed, 5 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/lib/librte_vhost/vhost_user.c
> > > > b/lib/librte_vhost/vhost_user.c
> > > > index 7f3e86778..71a0e7dd7 100644
> > > > --- a/lib/librte_vhost/vhost_user.c
> > > > +++ b/lib/librte_vhost/vhost_user.c
> > > > @@ -1296,7 +1296,11 @@ vhost_user_set_log_base(struct virtio_net
> > > > **pdev, struct VhostUserMsg *msg)
> > > >       dev->log_base = dev->log_addr + off;
> > > >       dev->log_size = size;
> > > > -    msg->size = sizeof(msg->payload.u64);
> > > > +    /*
> > > > +     * The spec is not clear about it (yet), but QEMU doesn't expect
> > > > +     * any payload in the reply.
> > > > +     */
> > > > +    msg->size = 0;
> > > 
> > > I think the spec is clear about it that no payload is
> > > expected in the reply:
> > > 
> > > https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L496
> > > 
> > It isn't really clear because there are two cases[0]:
> > 1. VHOST_USER_PROTOCOL_F_LOG_SHMFD not negotiated: In this case no reply
> >     has to be sent.
> > 2. VHOST_USER_PROTOCOL_F_LOG_SHMFD negotiated: In this case reply with
> >     empty payload hsa to be sent.
> > 
> > [0]: https://github.com/qemu/qemu/blob/7c69b7c849641a39ba3defa40d384a2ba24cd7a2/docs/interop/vhost-user.txt#L177
> > 
> 
> And I would add that N/A isn't clear, because SET_VRING_ADDR specifies
> N/A as slave payload, whereas the implementation does not implement a
> reply.

Good point.

> 
> > > But below line in the spec needs to be fixed:
> > > 
> > > https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L495
> > > 
> > 
> > Indeed.
> > 
> > > 
> > > >       return VH_RESULT_REPLY;
> > > >   }
> > > > -- 
> > > > 2.17.1
> > > >
diff mbox series

Patch

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 7f3e86778..71a0e7dd7 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1296,7 +1296,11 @@  vhost_user_set_log_base(struct virtio_net **pdev, struct VhostUserMsg *msg)
 	dev->log_base = dev->log_addr + off;
 	dev->log_size = size;
 
-	msg->size = sizeof(msg->payload.u64);
+	/*
+	 * The spec is not clear about it (yet), but QEMU doesn't expect
+	 * any payload in the reply.
+	 */
+	msg->size = 0;
 
 	return VH_RESULT_REPLY;
 }