[dpdk-dev] [PATCH] net: virtio: clear reserved vring properly at setup time

[dpdk-dev] [PATCH] net: virtio: clear reserved vring properly at setup time

[Maxime Coquelin]

After vring reservation, only the first bytes of the vring were
cleared.

This patch fixes this to clear the real size fo the vring.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---

Note: I found this bug while doing some code review, it is not a fix for
a problem I encountered.

---
 drivers/net/virtio/virtio_ethdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 850e3ba..336b3fc 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -387,7 +387,7 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev,
 		}
 	}
 
-	memset(mz->addr, 0, sizeof(mz->len));
+	memset(mz->addr, 0, mz->len);
 
 	vq->vq_ring_mem = mz->phys_addr;
 	vq->vq_ring_virt_mem = mz->addr;
-- 
2.7.4

Re: [dpdk-dev] [PATCH] net: virtio: clear reserved vring properly at setup time

[Yuanhan Liu]

On Mon, Jul 18, 2016 at 07:09:24PM +0200, Maxime Coquelin wrote:
> After vring reservation, only the first bytes of the vring were
> cleared.
> 
> This patch fixes this to clear the real size fo the vring.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
> 
> Note: I found this bug while doing some code review,

Nice catch!

> it is not a fix for
> a problem I encountered.

Yes, there should be no problem: vring memory is completely zero-ed
at port start stage by virtio_dev_vring_start().

> ---
>  drivers/net/virtio/virtio_ethdev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index 850e3ba..336b3fc 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -387,7 +387,7 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev,
>  		}
>  	}
>  
> -	memset(mz->addr, 0, sizeof(mz->len));
> +	memset(mz->addr, 0, mz->len);

Actually, I think we could simply drop the memset here. It's redundant,
as stated.

And to Thomas, I don't find a good reason to have this in 16.07. Let's
delay the apply to v16.11.

	--yliu

>  	vq->vq_ring_mem = mz->phys_addr;
>  	vq->vq_ring_virt_mem = mz->addr;
> -- 
> 2.7.4

Re: [dpdk-dev] [PATCH] net: virtio: clear reserved vring properly at setup time

[Maxime Coquelin]

On 07/19/2016 03:39 AM, Yuanhan Liu wrote:
> On Mon, Jul 18, 2016 at 07:09:24PM +0200, Maxime Coquelin wrote:
>> After vring reservation, only the first bytes of the vring were
>> cleared.
>>
>> This patch fixes this to clear the real size fo the vring.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>
>> Note: I found this bug while doing some code review,
>
> Nice catch!
>
>> it is not a fix for
>> a problem I encountered.
>
> Yes, there should be no problem: vring memory is completely zero-ed
> at port start stage by virtio_dev_vring_start().

Ok, thanks for the pointer.

>
>> ---
>>  drivers/net/virtio/virtio_ethdev.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
>> index 850e3ba..336b3fc 100644
>> --- a/drivers/net/virtio/virtio_ethdev.c
>> +++ b/drivers/net/virtio/virtio_ethdev.c
>> @@ -387,7 +387,7 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev,
>>  		}
>>  	}
>>
>> -	memset(mz->addr, 0, sizeof(mz->len));
>> +	memset(mz->addr, 0, mz->len);
>
> Actually, I think we could simply drop the memset here. It's redundant,
> as stated.
We can skip this patch then.

>
> And to Thomas, I don't find a good reason to have this in 16.07. Let's
> delay the apply to v16.11.
Yes, that's why I mentioned it didn't fixed any problem on my side.

So I propose we skip this patch, I'll resend one removing the memset for 
v16.11.

Thanks,
Maxime

>
> 	--yliu
>
>>  	vq->vq_ring_mem = mz->phys_addr;
>>  	vq->vq_ring_virt_mem = mz->addr;
>> --
>> 2.7.4

Re: [dpdk-dev] [PATCH] net: virtio: clear reserved vring properly at setup time

[Yuanhan Liu]

On Tue, Jul 19, 2016 at 07:31:35AM +0200, Maxime Coquelin wrote:
> >And to Thomas, I don't find a good reason to have this in 16.07. Let's
> >delay the apply to v16.11.
> Yes, that's why I mentioned it didn't fixed any problem on my side.
> 
> So I propose we skip this patch, I'll resend one removing the memset for
> v16.11.

Good to me.

	--yliu