On Mon, May 25, 2020 at 04:44:58PM +0200, Guennadi Liakhovetski wrote:
Linux supports running the RPMsg protocol over the VirtIO transport protocol, but currently there is only support for VirtIO clients and no support for a VirtIO server. This patch adds a vhost-based RPMsg server implementation.
Signed-off-by: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com
drivers/vhost/Kconfig | 7 + drivers/vhost/Makefile | 3 + drivers/vhost/rpmsg.c | 372 ++++++++++++++++++++++++++++++++++++++++++++ drivers/vhost/vhost_rpmsg.h | 74 +++++++++ 4 files changed, 456 insertions(+) create mode 100644 drivers/vhost/rpmsg.c create mode 100644 drivers/vhost/vhost_rpmsg.h
This patch triggers several checkpatch warnings, and from what I see none of them helping with code readability. Please consider addressing.
More comments to follow tomorrow.
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig index 2c75d16..c2113db 100644 --- a/drivers/vhost/Kconfig +++ b/drivers/vhost/Kconfig @@ -38,6 +38,13 @@ config VHOST_NET To compile this driver as a module, choose M here: the module will be called vhost_net.
+config VHOST_RPMSG
- tristate
- depends on VHOST
- ---help---
Vhost RPMsg API allows vhost drivers to communicate with VirtIO
drivers, using the RPMsg over VirtIO protocol.
config VHOST_SCSI tristate "VHOST_SCSI TCM fabric driver" depends on TARGET_CORE && EVENTFD diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile index f3e1897..9cf459d 100644 --- a/drivers/vhost/Makefile +++ b/drivers/vhost/Makefile @@ -2,6 +2,9 @@ obj-$(CONFIG_VHOST_NET) += vhost_net.o vhost_net-y := net.o
+obj-$(CONFIG_VHOST_RPMSG) += vhost_rpmsg.o +vhost_rpmsg-y := rpmsg.o
obj-$(CONFIG_VHOST_SCSI) += vhost_scsi.o vhost_scsi-y := scsi.o
diff --git a/drivers/vhost/rpmsg.c b/drivers/vhost/rpmsg.c new file mode 100644 index 00000000..609b9cf --- /dev/null +++ b/drivers/vhost/rpmsg.c @@ -0,0 +1,372 @@ +/* SPDX-License-Identifier: (GPL-2.0-only) */ +/*
- Copyright(c) 2020 Intel Corporation. All rights reserved.
- Author: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com
- vhost-RPMsg VirtIO interface
- */
+#include <linux/compat.h> +#include <linux/file.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/vhost.h> +#include <linux/virtio_rpmsg.h> +#include <uapi/linux/rpmsg.h>
+#include "vhost.h" +#include "vhost_rpmsg.h"
+/*
- All virtio-rpmsg virtual queue kicks always come with just one buffer -
- either input or output
- */
+static int vhost_rpmsg_get_single(struct vhost_virtqueue *vq) +{
- struct vhost_rpmsg *vr = container_of(vq->dev, struct vhost_rpmsg, dev);
- unsigned int out, in;
- int head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
&out, &in, NULL, NULL);
- if (head < 0) {
vq_err(vq, "%s(): error %d getting buffer\n",
__func__, head);
return head;
- }
- /* Nothing new? */
- if (head == vq->num)
return head;
- if (vq == &vr->vq[VIRTIO_RPMSG_RESPONSE] && (out || in != 1)) {
vq_err(vq,
"%s(): invalid %d input and %d output in response queue\n",
__func__, in, out);
goto return_buf;
- }
- if (vq == &vr->vq[VIRTIO_RPMSG_REQUEST] && (in || out != 1)) {
vq_err(vq,
"%s(): invalid %d input and %d output in request queue\n",
__func__, in, out);
goto return_buf;
- }
- return head;
+return_buf:
- /*
* FIXME: might need to return the buffer using vhost_add_used()
* or vhost_discard_vq_desc(). vhost_discard_vq_desc() is
* described as "being useful for error handling," but it makes
* the thus discarded buffers "unseen," so next time we look we
* retrieve them again?
*/
- return -EINVAL;
+}
+static const struct vhost_rpmsg_ept *vhost_rpmsg_ept_find(struct vhost_rpmsg *vr,
int addr)
+{
- unsigned int i;
- for (i = 0; i < vr->n_epts; i++)
if (vr->ept[i].addr == addr)
return vr->ept + i;
- return NULL;
+}
+/*
- if len < 0, then for reading a request, the complete virtual queue buffer
- size is prepared, for sending a response, the length in the iterator is used
- */
+int vhost_rpmsg_start_lock(struct vhost_rpmsg *vr,
struct vhost_rpmsg_iter *iter,
unsigned int qid, ssize_t len)
- __acquires(vq->mutex)
+{
- struct vhost_virtqueue *vq = vr->vq + qid;
- size_t tmp;
- if (qid >= VIRTIO_RPMSG_NUM_OF_VQS)
return -EINVAL;
- iter->vq = vq;
- mutex_lock(&vq->mutex);
- vhost_disable_notify(&vr->dev, vq);
- iter->head = vhost_rpmsg_get_single(vq);
- if (iter->head == vq->num)
iter->head = -EAGAIN;
- if (iter->head < 0)
goto unlock;
- tmp = vq->iov[0].iov_len;
- if (tmp < sizeof(iter->rhdr)) {
vq_err(vq, "%s(): size %zu too small\n", __func__, tmp);
iter->head = -ENOBUFS;
goto return_buf;
- }
- switch (qid) {
- case VIRTIO_RPMSG_REQUEST:
if (len < 0) {
len = tmp - sizeof(iter->rhdr);
} else if (tmp < sizeof(iter->rhdr) + len) {
iter->head = -ENOBUFS;
goto return_buf;
}
/* len is now the size of the payload */
iov_iter_init(&iter->iov_iter, WRITE,
vq->iov, 1, sizeof(iter->rhdr) + len);
/* Read the RPMSG header with endpoint addresses */
tmp = copy_from_iter(&iter->rhdr, sizeof(iter->rhdr),
&iter->iov_iter);
if (tmp != sizeof(iter->rhdr)) {
vq_err(vq, "%s(): got %zu instead of %zu\n", __func__,
tmp, sizeof(iter->rhdr));
iter->head = -EIO;
goto return_buf;
}
iter->ept = vhost_rpmsg_ept_find(vr, iter->rhdr.dst);
if (!iter->ept) {
vq_err(vq, "%s(): no endpoint with address %d\n",
__func__, iter->rhdr.dst);
iter->head = -ENOENT;
goto return_buf;
}
/* Let the endpoint read the payload */
if (iter->ept->read) {
ssize_t ret = iter->ept->read(vr, iter);
if (ret < 0) {
iter->head = ret;
goto return_buf;
}
iter->rhdr.len = ret;
} else {
iter->rhdr.len = 0;
}
/* Prepare for the response phase */
iter->rhdr.dst = iter->rhdr.src;
iter->rhdr.src = iter->ept->addr;
break;
- case VIRTIO_RPMSG_RESPONSE:
if (!iter->ept && iter->rhdr.dst != RPMSG_NS_ADDR) {
/*
* Usually the iterator is configured when processing a
* message on the request queue, but it's also possible
* to send a message on the response queue without a
* preceding request, in that case the iterator must
* contain source and destination addresses.
*/
iter->ept = vhost_rpmsg_ept_find(vr, iter->rhdr.src);
if (!iter->ept) {
iter->head = -ENOENT;
goto return_buf;
}
}
if (len < 0) {
len = tmp - sizeof(iter->rhdr);
} else if (tmp < sizeof(iter->rhdr) + len) {
iter->head = -ENOBUFS;
goto return_buf;
} else {
iter->rhdr.len = len;
}
/* len is now the size of the payload */
iov_iter_init(&iter->iov_iter, READ,
vq->iov, 1, sizeof(iter->rhdr) + len);
/* Write the RPMSG header with endpoint addresses */
tmp = copy_to_iter(&iter->rhdr, sizeof(iter->rhdr),
&iter->iov_iter);
if (tmp != sizeof(iter->rhdr)) {
iter->head = -EIO;
goto return_buf;
}
/* Let the endpoint write the payload */
if (iter->ept && iter->ept->write) {
ssize_t ret = iter->ept->write(vr, iter);
if (ret < 0) {
iter->head = ret;
goto return_buf;
}
}
break;
- }
- return 0;
+return_buf:
- /*
* FIXME: vhost_discard_vq_desc() or vhost_add_used(), see comment in
* vhost_rpmsg_get_single()
*/
+unlock:
- vhost_enable_notify(&vr->dev, vq);
- mutex_unlock(&vq->mutex);
- return iter->head;
+} +EXPORT_SYMBOL_GPL(vhost_rpmsg_start_lock);
+size_t vhost_rpmsg_copy(struct vhost_rpmsg *vr, struct vhost_rpmsg_iter *iter,
void *data, size_t size)
+{
- /*
* We could check for excess data, but copy_{to,from}_iter() don't do
* that either
*/
- if (iter->vq == vr->vq + VIRTIO_RPMSG_RESPONSE)
return copy_to_iter(data, size, &iter->iov_iter);
- return copy_from_iter(data, size, &iter->iov_iter);
+} +EXPORT_SYMBOL_GPL(vhost_rpmsg_copy);
+int vhost_rpmsg_finish_unlock(struct vhost_rpmsg *vr,
struct vhost_rpmsg_iter *iter)
- __releases(vq->mutex)
+{
- if (iter->head >= 0)
vhost_add_used_and_signal(iter->vq->dev, iter->vq, iter->head,
iter->rhdr.len + sizeof(iter->rhdr));
- vhost_enable_notify(&vr->dev, iter->vq);
- mutex_unlock(&iter->vq->mutex);
- return iter->head;
+} +EXPORT_SYMBOL_GPL(vhost_rpmsg_finish_unlock);
+/*
- Return false to terminate the external loop only if we fail to obtain either
- a request or a response buffer
- */
+static bool handle_rpmsg_req_single(struct vhost_rpmsg *vr,
struct vhost_virtqueue *vq)
+{
- struct vhost_rpmsg_iter iter;
- int ret = vhost_rpmsg_start_lock(vr, &iter, VIRTIO_RPMSG_REQUEST,
-EINVAL);
- if (!ret)
ret = vhost_rpmsg_finish_unlock(vr, &iter);
- if (ret < 0) {
if (ret != -EAGAIN)
vq_err(vq, "%s(): RPMSG processing failed %d\n",
__func__, ret);
return false;
- }
- if (!iter.ept->write)
return true;
- ret = vhost_rpmsg_start_lock(vr, &iter, VIRTIO_RPMSG_RESPONSE,
-EINVAL);
- if (!ret)
ret = vhost_rpmsg_finish_unlock(vr, &iter);
- if (ret < 0) {
vq_err(vq, "%s(): RPMSG finalising failed %d\n", __func__, ret);
return false;
- }
- return true;
+}
+static void handle_rpmsg_req_kick(struct vhost_work *work) +{
- struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
poll.work);
- struct vhost_rpmsg *vr = container_of(vq->dev, struct vhost_rpmsg, dev);
- while (handle_rpmsg_req_single(vr, vq))
;
+}
+/*
- initialise two virtqueues with an array of endpoints,
- request and response callbacks
- */
+void vhost_rpmsg_init(struct vhost_rpmsg *vr, const struct vhost_rpmsg_ept *ept,
unsigned int n_epts)
+{
- unsigned int i;
- for (i = 0; i < ARRAY_SIZE(vr->vq); i++)
vr->vq_p[i] = &vr->vq[i];
- /* vq[0]: host -> guest, vq[1]: host <- guest */
- vr->vq[VIRTIO_RPMSG_REQUEST].handle_kick = handle_rpmsg_req_kick;
- vr->ept = ept;
- vr->n_epts = n_epts;
- vhost_dev_init(&vr->dev, vr->vq_p, VIRTIO_RPMSG_NUM_OF_VQS,
UIO_MAXIOV, 0, 0, NULL);
+} +EXPORT_SYMBOL_GPL(vhost_rpmsg_init);
+void vhost_rpmsg_destroy(struct vhost_rpmsg *vr) +{
- if (vhost_dev_has_owner(&vr->dev))
vhost_poll_flush(&vr->vq[VIRTIO_RPMSG_REQUEST].poll);
- vhost_dev_cleanup(&vr->dev);
+} +EXPORT_SYMBOL_GPL(vhost_rpmsg_destroy);
+/* send namespace */ +int vhost_rpmsg_ns_announce(struct vhost_rpmsg *vr, const char *name,
unsigned int src)
+{
- struct vhost_rpmsg_iter iter = {
.rhdr = {
.src = 0,
.dst = RPMSG_NS_ADDR,
.flags = RPMSG_NS_CREATE, /* rpmsg_recv_single() */
},
- };
- struct rpmsg_ns_msg ns = {
.addr = src,
.flags = RPMSG_NS_CREATE, /* for rpmsg_ns_cb() */
- };
- int ret = vhost_rpmsg_start_lock(vr, &iter, VIRTIO_RPMSG_RESPONSE,
sizeof(ns));
- if (ret < 0)
return ret;
- strlcpy(ns.name, name, sizeof(ns.name));
- ret = vhost_rpmsg_copy(vr, &iter, &ns, sizeof(ns));
- if (ret != sizeof(ns))
vq_err(iter.vq, "%s(): added %d instead of %zu bytes\n",
__func__, ret, sizeof(ns));
- ret = vhost_rpmsg_finish_unlock(vr, &iter);
- if (ret < 0)
vq_err(iter.vq, "%s(): namespace announcement failed: %d\n",
__func__, ret);
- return ret;
+} +EXPORT_SYMBOL_GPL(vhost_rpmsg_ns_announce);
+MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Intel, Inc."); +MODULE_DESCRIPTION("Vhost RPMsg API"); diff --git a/drivers/vhost/vhost_rpmsg.h b/drivers/vhost/vhost_rpmsg.h new file mode 100644 index 00000000..5248ac9 --- /dev/null +++ b/drivers/vhost/vhost_rpmsg.h @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: (GPL-2.0) */ +/*
- Copyright(c) 2020 Intel Corporation. All rights reserved.
- Author: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com
- */
+#ifndef VHOST_RPMSG_H +#define VHOST_RPMSG_H
+#include <linux/uio.h> +#include <linux/virtio_rpmsg.h>
+#include "vhost.h"
+/* RPMsg uses two VirtQueues: one for each direction */ +enum {
- VIRTIO_RPMSG_RESPONSE, /* RPMsg response (host->guest) buffers */
- VIRTIO_RPMSG_REQUEST, /* RPMsg request (guest->host) buffers */
- /* Keep last */
- VIRTIO_RPMSG_NUM_OF_VQS,
+};
+struct vhost_rpmsg_ept;
+struct vhost_rpmsg_iter {
- struct iov_iter iov_iter;
- struct rpmsg_hdr rhdr;
- struct vhost_virtqueue *vq;
- const struct vhost_rpmsg_ept *ept;
- int head;
- void *priv;
+};
+struct vhost_rpmsg {
- struct vhost_dev dev;
- struct vhost_virtqueue vq[VIRTIO_RPMSG_NUM_OF_VQS];
- struct vhost_virtqueue *vq_p[VIRTIO_RPMSG_NUM_OF_VQS];
- const struct vhost_rpmsg_ept *ept;
- unsigned int n_epts;
+};
+struct vhost_rpmsg_ept {
- ssize_t (*read)(struct vhost_rpmsg *, struct vhost_rpmsg_iter *);
- ssize_t (*write)(struct vhost_rpmsg *, struct vhost_rpmsg_iter *);
- int addr;
+};
+static inline size_t vhost_rpmsg_iter_len(const struct vhost_rpmsg_iter *iter) +{
- return iter->rhdr.len;
+}
+#define VHOST_RPMSG_ITER(_src, _dst) { \
- .rhdr = { \
.src = _src, \
.dst = _dst, \
}, \
- }
+void vhost_rpmsg_init(struct vhost_rpmsg *vr, const struct vhost_rpmsg_ept *ept,
unsigned int n_epts);
+void vhost_rpmsg_destroy(struct vhost_rpmsg *vr); +int vhost_rpmsg_ns_announce(struct vhost_rpmsg *vr, const char *name,
unsigned int src);
+int vhost_rpmsg_start_lock(struct vhost_rpmsg *vr,
struct vhost_rpmsg_iter *iter,
unsigned int qid, ssize_t len);
+size_t vhost_rpmsg_copy(struct vhost_rpmsg *vr, struct vhost_rpmsg_iter *iter,
void *data, size_t size);
+int vhost_rpmsg_finish_unlock(struct vhost_rpmsg *vr,
struct vhost_rpmsg_iter *iter);
+#endif
1.9.3