diff mbox series

[RFC,10/27] vhost: retry translating IOVA after IOTLB miss

Message ID 20230331154259.1447831-11-maxime.coquelin@redhat.com (mailing list archive)
State Superseded, archived
Delegated to: Maxime Coquelin
Headers
Series Add VDUSE support to Vhost library |

Commit Message

Maxime Coquelin March 31, 2023, 3:42 p.m. UTC 
  Vhost-user backend IOTLB misses and updates are
asynchronous, so IOVA address translation function
just fails after having sent an IOTLB miss update if needed
entry was not in the IOTLB cache.

This is not the case for VDUSE, for which the needed IOTLB
update is returned directly when sending an IOTLB miss.

This patch retry again finding the needed entry in the
IOTLB cache after having sent an IOTLB miss.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/vhost/vhost.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Chenbo Xia May 5, 2023, 5:07 a.m. UTC | #1 
> -----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 10/27] vhost: retry translating IOVA after IOTLB miss
> 
> Vhost-user backend IOTLB misses and updates are
> asynchronous, so IOVA address translation function
> just fails after having sent an IOTLB miss update if needed
> entry was not in the IOTLB cache.
> 
> This is not the case for VDUSE, for which the needed IOTLB
> update is returned directly when sending an IOTLB miss.
> 
> This patch retry again finding the needed entry in the
> IOTLB cache after having sent an IOTLB miss.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/vhost/vhost.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
> index d35075b96c..4f16307e4d 100644
> --- a/lib/vhost/vhost.c
> +++ b/lib/vhost/vhost.c
> @@ -96,6 +96,12 @@ __vhost_iova_to_vva(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  		vhost_user_iotlb_rd_lock(vq);
>  	}
> 
> +	tmp_size = *size;
> +	/* Retry in case of VDUSE, as it is synchronous */
> +	vva = vhost_user_iotlb_cache_find(dev, iova, &tmp_size, perm);
> +	if (tmp_size == *size)
> +		return vva;
> +
>  	return 0;
>  }
> 
> --
> 2.39.2

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
diff mbox series

Patch

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index d35075b96c..4f16307e4d 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -96,6 +96,12 @@  __vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
 		vhost_user_iotlb_rd_lock(vq);
 	}
 
+	tmp_size = *size;
+	/* Retry in case of VDUSE, as it is synchronous */
+	vva = vhost_user_iotlb_cache_find(dev, iova, &tmp_size, perm);
+	if (tmp_size == *size)
+		return vva;
+
 	return 0;
 }