net/vhost: add parameter to enable postcopy

Introduce a new postcopy-support parameter to Vhost PMD that
passes the RTE_VHOST_USER_POSTCOPY_SUPPORT flag at vhost
device register time.

Flag should only be set if application does not prefault guest
memory using, for example, mlockall() syscall.

Default value is 0, meaning that postcopy support is disabled
unless specified explicitly.

Example to enable postcopy support for a given device:

--vdev 'net_vhost0,iface=/tmp/vhost-user1,postcopy-support=1'

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

diff --git a/doc/guides/nics/vhost.rst b/doc/guides/nics/vhost.rst
index 4f7ae89..23f2e87 100644 (file)
--- a/doc/guides/nics/vhost.rst
+++ b/doc/guides/nics/vhost.rst
@@ -71,6 +71,11 @@ The user can specify below arguments in `--vdev` option.
     It is used to enable iommu support in vhost library.
     (Default: 0 (disabled))
 
+#.  ``postcopy-support``:
+
+    It is used to enable postcopy live-migration support in vhost library.
+    (Default: 0 (disabled))
+
 Vhost PMD event handling
 ------------------------
 

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index a7604ff..55e51c8 100644 (file)
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -30,6 +30,7 @@ enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
 #define ETH_VHOST_CLIENT_ARG           "client"
 #define ETH_VHOST_DEQUEUE_ZERO_COPY    "dequeue-zero-copy"
 #define ETH_VHOST_IOMMU_SUPPORT                "iommu-support"
+#define ETH_VHOST_POSTCOPY_SUPPORT     "postcopy-support"
 #define VHOST_MAX_PKT_BURST 32
 
 static const char *valid_arguments[] = {
@@ -38,6 +39,7 @@ static const char *valid_arguments[] = {
        ETH_VHOST_CLIENT_ARG,
        ETH_VHOST_DEQUEUE_ZERO_COPY,
        ETH_VHOST_IOMMU_SUPPORT,
+       ETH_VHOST_POSTCOPY_SUPPORT,
        NULL
 };
 
@@ -1339,6 +1341,7 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
        int client_mode = 0;
        int dequeue_zero_copy = 0;
        int iommu_support = 0;
+       int postcopy_support = 0;
        struct rte_eth_dev *eth_dev;
        const char *name = rte_vdev_device_name(dev);
 
@@ -1410,6 +1413,16 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
                        flags |= RTE_VHOST_USER_IOMMU_SUPPORT;
        }
 
+       if (rte_kvargs_count(kvlist, ETH_VHOST_POSTCOPY_SUPPORT) == 1) {
+               ret = rte_kvargs_process(kvlist, ETH_VHOST_POSTCOPY_SUPPORT,
+                                        &open_int, &postcopy_support);
+               if (ret < 0)
+                       goto out_free;
+
+               if (postcopy_support)
+                       flags |= RTE_VHOST_USER_POSTCOPY_SUPPORT;
+       }
+
        if (dev->device.numa_node == SOCKET_ID_ANY)
                dev->device.numa_node = rte_socket_id();