Re: [External] Re: [RFC v1 1/6] virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit

From: Jiang Wang .
Date: Mon Jun 21 2021 - 13:24:36 EST

On Fri, Jun 18, 2021 at 2:40 AM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:
>
> On Wed, Jun 09, 2021 at 11:24:53PM +0000, Jiang Wang wrote:
> >When this feature is enabled, allocate 5 queues,
> >otherwise, allocate 3 queues to be compatible with
> >old QEMU versions.
> >
> >Signed-off-by: Jiang Wang <jiang.wang@xxxxxxxxxxxxx>
> >---
> > drivers/vhost/vsock.c | 3 +-
> > include/linux/virtio_vsock.h | 9 +++++
> > include/uapi/linux/virtio_vsock.h | 3 ++
> > net/vmw_vsock/virtio_transport.c | 73 +++++++++++++++++++++++++++++++++++----
> > 4 files changed, 80 insertions(+), 8 deletions(-)
> >
> >diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> >index 5e78fb719602..81d064601093 100644
> >--- a/drivers/vhost/vsock.c
> >+++ b/drivers/vhost/vsock.c
> >@@ -31,7 +31,8 @@
> >
> > enum {
> > VHOST_VSOCK_FEATURES = VHOST_FEATURES |
> >- (1ULL << VIRTIO_F_ACCESS_PLATFORM)
> >+ (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
> >+ (1ULL << VIRTIO_VSOCK_F_DGRAM)
> > };
> >
> > enum {
> >diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> >index dc636b727179..ba3189ed9345 100644
> >--- a/include/linux/virtio_vsock.h
> >+++ b/include/linux/virtio_vsock.h
> >@@ -18,6 +18,15 @@ enum {
> > VSOCK_VQ_MAX = 3,
> > };
> >
> >+enum {
> >+ VSOCK_VQ_STREAM_RX = 0, /* for host to guest data */
> >+ VSOCK_VQ_STREAM_TX = 1, /* for guest to host data */
> >+ VSOCK_VQ_DGRAM_RX = 2,
> >+ VSOCK_VQ_DGRAM_TX = 3,
> >+ VSOCK_VQ_EX_EVENT = 4,
> >+ VSOCK_VQ_EX_MAX = 5,
> >+};
> >+
> > /* Per-socket state (accessed via vsk->trans) */
> > struct virtio_vsock_sock {
> > struct vsock_sock *vsk;
> >diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
> >index 1d57ed3d84d2..b56614dff1c9 100644
> >--- a/include/uapi/linux/virtio_vsock.h
> >+++ b/include/uapi/linux/virtio_vsock.h
> >@@ -38,6 +38,9 @@
> > #include <linux/virtio_ids.h>
> > #include <linux/virtio_config.h>
> >
> >+/* The feature bitmap for virtio net */
> >+#define VIRTIO_VSOCK_F_DGRAM 0 /* Host support dgram vsock */
> >+
> > struct virtio_vsock_config {
> > __le64 guest_cid;
> > } __attribute__((packed));
> >diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> >index 2700a63ab095..7dcb8db23305 100644
> >--- a/net/vmw_vsock/virtio_transport.c
> >+++ b/net/vmw_vsock/virtio_transport.c
> >@@ -27,7 +27,8 @@ static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
> >
> > struct virtio_vsock {
> > struct virtio_device *vdev;
> >- struct virtqueue *vqs[VSOCK_VQ_MAX];
> >+ struct virtqueue **vqs;
> >+ bool has_dgram;
> >
> > /* Virtqueue processing is deferred to a workqueue */
> > struct work_struct tx_work;
> >@@ -333,7 +334,10 @@ static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
> > struct scatterlist sg;
> > struct virtqueue *vq;
> >
> >- vq = vsock->vqs[VSOCK_VQ_EVENT];
> >+ if (vsock->has_dgram)
> >+ vq = vsock->vqs[VSOCK_VQ_EX_EVENT];
> >+ else
> >+ vq = vsock->vqs[VSOCK_VQ_EVENT];
> >
> > sg_init_one(&sg, event, sizeof(*event));
> >
> >@@ -351,7 +355,10 @@ static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
> > virtio_vsock_event_fill_one(vsock, event);
> > }
> >
> >- virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
> >+ if (vsock->has_dgram)
> >+ virtqueue_kick(vsock->vqs[VSOCK_VQ_EX_EVENT]);
> >+ else
> >+ virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
> > }
> >
> > static void virtio_vsock_reset_sock(struct sock *sk)
> >@@ -391,7 +398,10 @@ static void virtio_transport_event_work(struct work_struct *work)
> > container_of(work, struct virtio_vsock, event_work);
> > struct virtqueue *vq;
> >
> >- vq = vsock->vqs[VSOCK_VQ_EVENT];
> >+ if (vsock->has_dgram)
> >+ vq = vsock->vqs[VSOCK_VQ_EX_EVENT];
> >+ else
> >+ vq = vsock->vqs[VSOCK_VQ_EVENT];
> >
> > mutex_lock(&vsock->event_lock);
> >
> >@@ -411,7 +421,10 @@ static void virtio_transport_event_work(struct work_struct *work)
> > }
> > } while (!virtqueue_enable_cb(vq));
> >
> >- virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
> >+ if (vsock->has_dgram)
> >+ virtqueue_kick(vsock->vqs[VSOCK_VQ_EX_EVENT]);
> >+ else
> >+ virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
> > out:
> > mutex_unlock(&vsock->event_lock);
> > }
> >@@ -434,6 +447,10 @@ static void virtio_vsock_tx_done(struct virtqueue *vq)
> > queue_work(virtio_vsock_workqueue, &vsock->tx_work);
> > }
> >
> >+static void virtio_vsock_dgram_tx_done(struct virtqueue *vq)
> >+{
> >+}
> >+
> > static void virtio_vsock_rx_done(struct virtqueue *vq)
> > {
> > struct virtio_vsock *vsock = vq->vdev->priv;
> >@@ -443,6 +460,10 @@ static void virtio_vsock_rx_done(struct virtqueue *vq)
> > queue_work(virtio_vsock_workqueue, &vsock->rx_work);
> > }
> >
> >+static void virtio_vsock_dgram_rx_done(struct virtqueue *vq)
> >+{
> >+}
> >+
> > static struct virtio_transport virtio_transport = {
> > .transport = {
> > .module = THIS_MODULE,
> >@@ -545,13 +566,29 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
> > virtio_vsock_tx_done,
> > virtio_vsock_event_done,
> > };
> >+ vq_callback_t *ex_callbacks[] = {
>
> 'ex' is not clear, maybe better 'dgram'?
>
sure.

> What happen if F_DGRAM is negotiated, but not F_STREAM?
>
Hmm. In my mind, F_STREAM is always negotiated. Do we want to add
support when F_STREAM is not negotiated?

> >+ virtio_vsock_rx_done,
> >+ virtio_vsock_tx_done,
> >+ virtio_vsock_dgram_rx_done,
> >+ virtio_vsock_dgram_tx_done,
> >+ virtio_vsock_event_done,
> >+ };
> >+
> > static const char * const names[] = {
> > "rx",
> > "tx",
> > "event",
> > };
> >+ static const char * const ex_names[] = {
> >+ "rx",
> >+ "tx",
> >+ "dgram_rx",
> >+ "dgram_tx",
> >+ "event",
> >+ };
> >+
> > struct virtio_vsock *vsock = NULL;
> >- int ret;
> >+ int ret, max_vq;
> >
> > ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
> > if (ret)
> >@@ -572,9 +609,30 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
> >
> > vsock->vdev = vdev;
> >
> >- ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
> >+ if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_DGRAM))
> >+ vsock->has_dgram = true;
> >+
> >+ if (vsock->has_dgram)
> >+ max_vq = VSOCK_VQ_EX_MAX;
> >+ else
> >+ max_vq = VSOCK_VQ_MAX;
> >+
> >+ vsock->vqs = kmalloc_array(max_vq, sizeof(struct virtqueue *), GFP_KERNEL);
> >+ if (!vsock->vqs) {
> >+ ret = -ENOMEM;
> >+ goto out;
> >+ }
> >+
> >+ if (vsock->has_dgram) {
> >+ ret = virtio_find_vqs(vsock->vdev, max_vq,
> >+ vsock->vqs, ex_callbacks, ex_names,
> >+ NULL);
> >+ } else {
> >+ ret = virtio_find_vqs(vsock->vdev, max_vq,
> > vsock->vqs, callbacks, names,
> > NULL);
> >+ }
> >+
> > if (ret < 0)
> > goto out;
> >
> >@@ -695,6 +753,7 @@ static struct virtio_device_id id_table[] = {
> > };
> >
> > static unsigned int features[] = {
> >+ VIRTIO_VSOCK_F_DGRAM,
> > };
> >
> > static struct virtio_driver virtio_vsock_driver = {
> >--
> >2.11.0
> >
>