Re: [RFC 12/27] vhost: add IOTLB cache entry removal callback

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 5/5/23 07:07, Xia, Chenbo wrote:
> Hi Maxime,
> 
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Friday, March 31, 2023 11:43 PM
>> To: dev@dpdk.org; david.marchand@redhat.com; Xia, Chenbo
>> <chenbo.xia@intel.com>; mkp@redhat.com; fbl@redhat.com;
>> jasowang@redhat.com; Liang, Cunming <cunming.liang@intel.com>; Xie, Yongji
>> <xieyongji@bytedance.com>; echaudro@redhat.com; eperezma@redhat.com;
>> amorenoz@redhat.com
>> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Subject: [RFC 12/27] vhost: add IOTLB cache entry removal callback
>>
>> VDUSE will need to munmap() the IOTLB entry on removal
>> from the cache, as it performs mmap() before insertion.
>>
>> This patch introduces a callback that VDUSE layer will
>> implement to achieve this.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>   lib/vhost/iotlb.c | 12 ++++++++++++
>>   lib/vhost/vhost.h |  4 ++++
>>   2 files changed, 16 insertions(+)
>>
>> diff --git a/lib/vhost/iotlb.c b/lib/vhost/iotlb.c
>> index 188dfb8e38..86b0be62b4 100644
>> --- a/lib/vhost/iotlb.c
>> +++ b/lib/vhost/iotlb.c
>> @@ -25,6 +25,15 @@ struct vhost_iotlb_entry {
>>
>>   #define IOTLB_CACHE_SIZE 2048
>>
>> +static void
>> +vhost_user_iotlb_remove_notify(struct virtio_net *dev, struct
>> vhost_iotlb_entry *entry)
>> +{
>> +	if (dev->backend_ops->iotlb_remove_notify == NULL)
>> +		return;
>> +
>> +	dev->backend_ops->iotlb_remove_notify(entry->uaddr, entry->uoffset,
>> entry->size);
>> +}
>> +
>>   static bool
>>   vhost_user_iotlb_share_page(struct vhost_iotlb_entry *a, struct
>> vhost_iotlb_entry *b)
>>   {
>> @@ -198,6 +207,7 @@ vhost_user_iotlb_cache_remove_all(struct virtio_net
>> *dev)
>>   		vhost_user_iotlb_set_dump(node);
>>
>>   		TAILQ_REMOVE(&dev->iotlb_list, node, next);
>> +		vhost_user_iotlb_remove_notify(dev, node);
>>   		vhost_user_iotlb_pool_put(dev, node);
>>   	}
>>
>> @@ -223,6 +233,7 @@ vhost_user_iotlb_cache_random_evict(struct virtio_net
>> *dev)
>>   			vhost_user_iotlb_clear_dump(node, prev_node, next_node);
>>
>>   			TAILQ_REMOVE(&dev->iotlb_list, node, next);
>> +			vhost_user_iotlb_remove_notify(dev, node);
>>   			vhost_user_iotlb_pool_put(dev, node);
>>   			dev->iotlb_cache_nr--;
>>   			break;
>> @@ -314,6 +325,7 @@ vhost_user_iotlb_cache_remove(struct virtio_net *dev,
>> uint64_t iova, uint64_t si
>>   			vhost_user_iotlb_clear_dump(node, prev_node, next_node);
>>
>>   			TAILQ_REMOVE(&dev->iotlb_list, node, next);
>> +			vhost_user_iotlb_remove_notify(dev, node);
>>   			vhost_user_iotlb_pool_put(dev, node);
>>   			dev->iotlb_cache_nr--;
>>   		} else {
>> diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
>> index cc5c707205..2ad26f6951 100644
>> --- a/lib/vhost/vhost.h
>> +++ b/lib/vhost/vhost.h
>> @@ -89,10 +89,14 @@
>>   	for (iter = val; iter < num; iter++)
>>   #endif
>>
>> +struct virtio_net;
> 
> Adding this in patch 13 could be better since this patch is not using it.

Right, I changed vhost_iotlb_remove_notify cb prototype but forgot to 
remove struct virtio_net afterwards.

Changed in upcoming v2.

Thanks,
Maxime


> Thanks,
> Chenbo
> 
>> +typedef void (*vhost_iotlb_remove_notify)(uint64_t addr, uint64_t off,
>> uint64_t size);
>> +
>>   /**
>>    * Structure that contains backend-specific ops.
>>    */
>>   struct vhost_backend_ops {
>> +	vhost_iotlb_remove_notify iotlb_remove_notify;
>>   };
>>
>>   /**
>> --
>> 2.39.2
>