This is the first of a series of patches, whose purpose is to add
support for the virtio-vhost-user transport. This is a vhost-user
transport implementation that is different from the default AF_UNIX
transport. It uses the virtio-vhost-user PCI device in order to tunnel
vhost-user protocol messages over virtio. This lets guests act as vhost
device backends for other guests.
File descriptor passing is specific to the AF_UNIX vhost-user protocol
transport. In order to add support for additional transports, it is
necessary to extract transport-specific code from the main vhost-user
code.
This patch introduces struct vhost_transport_ops and associates each
device with a transport. Core vhost-user code calls into
vhost_transport_ops to perform transport-specific operations.
Notifying callfd is a transport-specific operation, so it belongs to
trans_af_unix.c.
Several more patches follow this one to complete the task of moving
AF_UNIX transport code out of core vhost-user code.
Signed-off-by: Nikos Dragazis <ndraga...@arrikto.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
lib/librte_vhost/Makefile | 2 +-
lib/librte_vhost/trans_af_unix.c | 20 ++++++++++++++++++++
lib/librte_vhost/vhost.c | 1 +
lib/librte_vhost/vhost.h | 34 +++++++++++++++++++++++++++++-----
4 files changed, 51 insertions(+), 6 deletions(-)
create mode 100644 lib/librte_vhost/trans_af_unix.c
diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
index 8623e91..5ff5fb2 100644
--- a/lib/librte_vhost/Makefile
+++ b/lib/librte_vhost/Makefile
@@ -23,7 +23,7 @@ LDLIBS += -lrte_eal -lrte_mempool -lrte_mbuf -lrte_ethdev
-lrte_net
# all source are stored in SRCS-y
SRCS-$(CONFIG_RTE_LIBRTE_VHOST) := fd_man.c iotlb.c socket.c vhost.c \
- vhost_user.c virtio_net.c vdpa.c
+ vhost_user.c virtio_net.c vdpa.c
trans_af_unix.c
# install includes
SYMLINK-$(CONFIG_RTE_LIBRTE_VHOST)-include += rte_vhost.h rte_vdpa.h
diff --git a/lib/librte_vhost/trans_af_unix.c b/lib/librte_vhost/trans_af_unix.c
new file mode 100644
index 0000000..3f0c308
--- /dev/null
+++ b/lib/librte_vhost/trans_af_unix.c
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2010-2018 Intel Corporation
+ * Copyright(c) 2017 Red Hat, Inc.
+ * Copyright(c) 2019 Arrikto Inc.
+ */
+
+#include "vhost.h"
+
+static int
+af_unix_vring_call(struct virtio_net *dev __rte_unused,
+ struct vhost_virtqueue *vq)
+{
+ if (vq->callfd >= 0)
+ eventfd_write(vq->callfd, (eventfd_t)1);
+ return 0;
+}
+
+const struct vhost_transport_ops af_unix_trans_ops = {
+ .vring_call = af_unix_vring_call,
+};
diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 981837b..a36bc01 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -507,6 +507,7 @@ vhost_new_device(void)
dev->vid = i;
dev->flags = VIRTIO_DEV_BUILTIN_VIRTIO_NET;
dev->slave_req_fd = -1;
+ dev->trans_ops = &af_unix_trans_ops;
dev->vdpa_dev_id = -1;
dev->postcopy_ufd = -1;
rte_spinlock_init(&dev->slave_req_lock);
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 884befa..077f213 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -286,6 +286,30 @@ struct guest_page {
uint64_t size;
};
+struct virtio_net;
+
+/**
+ * A structure containing function pointers for transport-specific operations.
+ */
+struct vhost_transport_ops {
+ /**
+ * Notify the guest that used descriptors have been added to the vring.
+ * The VRING_AVAIL_F_NO_INTERRUPT flag and event idx have already been
checked
+ * so this function just needs to perform the notification.
+ *
+ * @param dev
+ * vhost device
+ * @param vq
+ * vhost virtqueue
+ * @return
+ * 0 on success, -1 on failure
+ */
+ int (*vring_call)(struct virtio_net *dev, struct vhost_virtqueue *vq);
+};
+
+/** The traditional AF_UNIX vhost-user protocol transport. */
+extern const struct vhost_transport_ops af_unix_trans_ops;
+
/**
* Device structure contains all configuration information relating
* to the device.
@@ -312,6 +336,7 @@ struct virtio_net {
uint16_t mtu;
struct vhost_device_ops const *notify_ops;
+ struct vhost_transport_ops const *trans_ops;
uint32_t nr_guest_pages;
uint32_t max_guest_pages;
@@ -544,12 +569,11 @@ vhost_vring_call_split(struct virtio_net *dev, struct
vhost_virtqueue *vq)
if ((vhost_need_event(vhost_used_event(vq), new, old) &&
(vq->callfd >= 0)) ||
unlikely(!signalled_used_valid))
- eventfd_write(vq->callfd, (eventfd_t) 1);
+ dev->trans_ops->vring_call(dev, vq);
} else {
/* Kick the guest if necessary. */
- if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
- && (vq->callfd >= 0))
- eventfd_write(vq->callfd, (eventfd_t)1);
+ if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
+ dev->trans_ops->vring_call(dev, vq);
}
}
@@ -601,7 +625,7 @@ vhost_vring_call_packed(struct virtio_net *dev, struct
vhost_virtqueue *vq)
kick = true;
kick:
if (kick)
- eventfd_write(vq->callfd, (eventfd_t)1);
+ dev->trans_ops->vring_call(dev, vq);
}
static __rte_always_inline void
--
2.7.4
