Hi Guennadi,

On Mon, May 25, 2020 at 04:44:56PM +0200, Guennadi Liakhovetski wrote:

virtio_rpmsg_bus.c keeps RPMsg protocol structure declarations and common defines like the ones, needed for name-space announcements, internal. Move them to common headers instead.

Signed-off-by: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com

drivers/rpmsg/virtio_rpmsg_bus.c | 78 +------------------------------------- include/linux/virtio_rpmsg.h | 81 ++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/rpmsg.h | 3 ++ 3 files changed, 86 insertions(+), 76 deletions(-) create mode 100644 include/linux/virtio_rpmsg.h

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c index 07d4f33..f3bd050 100644 --- a/drivers/rpmsg/virtio_rpmsg_bus.c +++ b/drivers/rpmsg/virtio_rpmsg_bus.c @@ -25,7 +25,9 @@ #include <linux/virtio.h> #include <linux/virtio_ids.h> #include <linux/virtio_config.h> +#include <linux/virtio_rpmsg.h> #include <linux/wait.h> +#include <uapi/linux/rpmsg.h>

#include "rpmsg_internal.h"

@@ -69,58 +71,6 @@ struct virtproc_info { struct rpmsg_endpoint *ns_ept; };

-/* The feature bitmap for virtio rpmsg */ -#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */

-/**

• • struct rpmsg_hdr - common header for all rpmsg messages
• • @src: source address
• • @dst: destination address
• • @reserved: reserved for future use
• • @len: length of payload (in bytes)
• • @flags: message flags
• • @data: @len bytes of message payload data
• • Every message sent(/received) on the rpmsg bus begins with this header.
• */

-struct rpmsg_hdr {

• u32 src;
• u32 dst;
• u32 reserved;
• u16 len;
• u16 flags;
• u8 data[];

-} __packed;

-/**

• • struct rpmsg_ns_msg - dynamic name service announcement message
• • @name: name of remote service that is published
• • @addr: address of remote service that is published
• • @flags: indicates whether service is created or destroyed
• • This message is sent across to publish a new service, or announce
• • about its removal. When we receive these messages, an appropriate
• • rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
• • or ->remove() handler of the appropriate rpmsg driver will be invoked
• • (if/as-soon-as one is registered).
• */

-struct rpmsg_ns_msg {

• char name[RPMSG_NAME_SIZE];
• u32 addr;
• u32 flags;

-} __packed;

-/**

• • enum rpmsg_ns_flags - dynamic name service announcement flags
• • @RPMSG_NS_CREATE: a new remote service was just created
• • @RPMSG_NS_DESTROY: a known remote service was just destroyed
• */

-enum rpmsg_ns_flags {

• RPMSG_NS_CREATE = 0,
• RPMSG_NS_DESTROY = 1,

-};

/**

• @vrp: the remote processor this channel belongs to

*/ @@ -134,36 +84,12 @@ struct virtio_rpmsg_channel { container_of(_rpdev, struct virtio_rpmsg_channel, rpdev)

/*

• • We're allocating buffers of 512 bytes each for communications. The
• • number of buffers will be computed from the number of buffers supported
• • by the vring, upto a maximum of 512 buffers (256 in each direction).
• • Each buffer will have 16 bytes for the msg header and 496 bytes for
• • the payload.
• • This will utilize a maximum total space of 256KB for the buffers.
• • We might also want to add support for user-provided buffers in time.
• • This will allow bigger buffer size flexibility, and can also be used
• • to achieve zero-copy messaging.
• • Note that these numbers are purely a decision of this driver - we
• • can change this without changing anything in the firmware of the remote
• • processor.
• */

-#define MAX_RPMSG_NUM_BUFS (512) -#define MAX_RPMSG_BUF_SIZE (512)

-/*

• Local addresses are dynamically allocated on-demand.
• We do not dynamically assign addresses from the low 1024 range,
• in order to reserve that address range for predefined services.

*/ #define RPMSG_RESERVED_ADDRESSES (1024)

-/* Address 53 is reserved for advertising remote services */ -#define RPMSG_NS_ADDR (53)

static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept); static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len); static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, diff --git a/include/linux/virtio_rpmsg.h b/include/linux/virtio_rpmsg.h new file mode 100644 index 00000000..bf2fd69 --- /dev/null +++ b/include/linux/virtio_rpmsg.h @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0

+#ifndef _LINUX_VIRTIO_RPMSG_H +#define _LINUX_VIRTIO_RPMSG_H

+#include <linux/mod_devicetable.h>

+/* Address 53 is reserved for advertising remote services */ +#define RPMSG_NS_ADDR (53)

+/*

• • We're allocating buffers of 512 bytes each for communications. The
• • number of buffers will be computed from the number of buffers supported
• • by the vring, upto a maximum of 512 buffers (256 in each direction).
• • Each buffer will have 16 bytes for the msg header and 496 bytes for
• • the payload.
• • This will utilize a maximum total space of 256KB for the buffers.
• • We might also want to add support for user-provided buffers in time.
• • This will allow bigger buffer size flexibility, and can also be used
• • to achieve zero-copy messaging.
• • Note that these numbers are purely a decision of this driver - we
• • can change this without changing anything in the firmware of the remote
• • processor.
• */

+#define MAX_RPMSG_NUM_BUFS 512 +#define MAX_RPMSG_BUF_SIZE 512

+/**

• • struct rpmsg_hdr - common header for all rpmsg messages
• • @src: source address
• • @dst: destination address
• • @reserved: reserved for future use
• • @len: length of payload (in bytes)
• • @flags: message flags
• • @data: @len bytes of message payload data
• • Every message sent(/received) on the rpmsg bus begins with this header.
• */

+struct rpmsg_hdr {

• u32 src;
• u32 dst;
• u32 reserved;
• u16 len;
• u16 flags;
• u8 data[];

+} __packed;

+/**

• • struct rpmsg_ns_msg - dynamic name service announcement message
• • @name: name of remote service that is published
• • @addr: address of remote service that is published
• • @flags: indicates whether service is created or destroyed
• • This message is sent across to publish a new service, or announce
• • about its removal. When we receive these messages, an appropriate
• • rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
• • or ->remove() handler of the appropriate rpmsg driver will be invoked
• • (if/as-soon-as one is registered).
• */

+struct rpmsg_ns_msg {

• char name[RPMSG_NAME_SIZE];
• u32 addr;
• u32 flags;

+} __packed;

+/**

• • enum rpmsg_ns_flags - dynamic name service announcement flags
• • @RPMSG_NS_CREATE: a new remote service was just created
• • @RPMSG_NS_DESTROY: a known remote service was just destroyed
• */

+enum rpmsg_ns_flags {

• RPMSG_NS_CREATE = 0,
• RPMSG_NS_DESTROY = 1,

+};

I have started reviewing this set and comments will (likely) come over a few days.

For this file, I would have appreciated seeing the structure and defines laid out in the same order in this file as they were in virtio_rpmsg_bus.c. That way I don't have to check every item to make sure nothing has been missed. Not a big problem but something to consider for the next revivions.

The good thing is that it did not break my complation so with above:

Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org

+#endif diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h index e14c6da..d669c04 100644 --- a/include/uapi/linux/rpmsg.h +++ b/include/uapi/linux/rpmsg.h @@ -24,4 +24,7 @@ struct rpmsg_endpoint_info { #define RPMSG_CREATE_EPT_IOCTL _IOW(0xb5, 0x1, struct rpmsg_endpoint_info) #define RPMSG_DESTROY_EPT_IOCTL _IO(0xb5, 0x2)

+/* The feature bitmap for virtio rpmsg */ +#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */

#endif

1.9.3

On Mon, May 25, 2020 at 04:44:57PM +0200, Guennadi Liakhovetski wrote:

rpmsg_create_ept() takes struct rpmsg_channel_info chinfo as its last argument, not a u32 value.

Signed-off-by: Guennadi Liakhovetski guennadi.liakhovetski@linux.intel.com

Documentation/rpmsg.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/rpmsg.txt b/Documentation/rpmsg.txt index 24b7a9e..4f9bc4f 100644 --- a/Documentation/rpmsg.txt +++ b/Documentation/rpmsg.txt @@ -194,7 +194,7 @@ Returns 0 on success and an appropriate error value on failure.

struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *rpdev, void (*cb)(struct rpmsg_channel *, void *, int, void *, u32),

• void *priv, u32 addr);
  

• void *priv, struct rpmsg_channel_info chinfo);
  

The second argument, i.e *cb is also wrong. The first argument to the function pointer is a struct rpmsg_device rather than a rpmsg_channel. Please fix that while at it by simply using "rpmsg_rx_cb_t cb", the same way it is in linux/rpmsg.h.

Thanks, Mathieu

every rpmsg address in the system is bound to an rx callback (so when inbound messages arrive, they are dispatched by the rpmsg bus using the -- 1.9.3

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

Hi Mathieu,

On Tue, May 26, 2020 at 02:50:39PM -0600, Mathieu Poirier wrote:

Hi Guennadi,

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

[snip]

...

+/* 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() */
  

• };

I think it would be worth mentioning that someone on the guest side needs to call register_virtio_device() with a vdev->id->device == VIRTIO_ID_RPMSG, something that will match that device to the virtio_ipc_driver. Otherwise the connection between them is very difficult to establish.

In fact you don't want to use just one ID, as you add more drivers, using RPMsg over VirtIO, you'll add more IDs to the ID table in virtio_rpmsg_bus.c. I am adding a comment at the top of this file to explain that.

Thanks Guennadi

Aside from the checkpatch warning I already pointed out, I don't have much else.

Thanks, Mathieu

...

• 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