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

[Maxime Coquelin]

On 5/5/23 07:07, Xia, Chenbo wrote:
Hi Maxime,

-----Original Message-----
From: Maxime Coquelin <maxime.coque...@redhat.com>
Sent: Friday, March 31, 2023 11:43 PM
To: dev@dpdk.org; david.march...@redhat.com; Xia, Chenbo
<chenbo....@intel.com>; m...@redhat.com; f...@redhat.com;
jasow...@redhat.com; Liang, Cunming <cunming.li...@intel.com>; Xie, Yongji
<xieyon...@bytedance.com>; echau...@redhat.com; epere...@redhat.com;
amore...@redhat.com
Cc: Maxime Coquelin <maxime.coque...@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.coque...@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