Re: [PATCH v4] rpmsg: virtio: add endianness conversions

[Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>]

Bjorn, Ohad, is this one good to go? Can we proceed with the next step:

https://marc.info/?l=kvm&m=159060274705978&w=2

Thanks
Guennadi

On Tue, Jul 07, 2020 at 09:38:37AM -0600, Mathieu Poirier wrote:
> On Tue, 7 Jul 2020 at 09:34, Guennadi Liakhovetski
> <guennadi.liakhovetski@linux.intel.com> wrote:
> >
> > According to the VirtIO 1.0 spec data, sent over virtual queues must
> > be in little-endian format. Update the RPMsg VirtIO implementation
> > to enforce that but let legacy configurations continue use native
> > endianness.
> >
> > Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
> > Tested-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
> > ---
> >
> > Mathieu, I had to remove your "Reviewed-by" because this is a modified version...
> >
> > v4: fix a left-over use of an LE value in calculation - thanks to Arnaud for catching!
> 
> It is indeed a good catch
> 
> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> 
> >
> > v3: use the virtio_byteorder.h header
> >
> > v2: Following suggestions from Michael and Mathieu switch to using virtio16/32
> > types and conversion functions.
> >
> >  drivers/rpmsg/virtio_rpmsg_bus.c | 63 +++++++++++++++++---------------
> >  1 file changed, 34 insertions(+), 29 deletions(-)
> >
> > diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> > index 07d4f3374098..9006fc7f73d0 100644
> > --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> > +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> > @@ -23,6 +23,7 @@
> >  #include <linux/slab.h>
> >  #include <linux/sched.h>
> >  #include <linux/virtio.h>
> > +#include <linux/virtio_byteorder.h>
> >  #include <linux/virtio_ids.h>
> >  #include <linux/virtio_config.h>
> >  #include <linux/wait.h>
> > @@ -84,11 +85,11 @@ struct virtproc_info {
> >   * 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;
> > +       __virtio32 src;
> > +       __virtio32 dst;
> > +       __virtio32 reserved;
> > +       __virtio16 len;
> > +       __virtio16 flags;
> >         u8 data[];
> >  } __packed;
> >
> > @@ -106,8 +107,8 @@ struct rpmsg_hdr {
> >   */
> >  struct rpmsg_ns_msg {
> >         char name[RPMSG_NAME_SIZE];
> > -       u32 addr;
> > -       u32 flags;
> > +       __virtio32 addr;
> > +       __virtio32 flags;
> >  } __packed;
> >
> >  /**
> > @@ -335,8 +336,8 @@ static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev)
> >                 struct rpmsg_ns_msg nsm;
> >
> >                 strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
> > -               nsm.addr = rpdev->ept->addr;
> > -               nsm.flags = RPMSG_NS_CREATE;
> > +               nsm.addr = cpu_to_virtio32(vrp->vdev, rpdev->ept->addr);
> > +               nsm.flags = cpu_to_virtio32(vrp->vdev, RPMSG_NS_CREATE);
> >
> >                 err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
> >                 if (err)
> > @@ -359,8 +360,8 @@ static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
> >                 struct rpmsg_ns_msg nsm;
> >
> >                 strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
> > -               nsm.addr = rpdev->ept->addr;
> > -               nsm.flags = RPMSG_NS_DESTROY;
> > +               nsm.addr = cpu_to_virtio32(vrp->vdev, rpdev->ept->addr);
> > +               nsm.flags = cpu_to_virtio32(vrp->vdev, RPMSG_NS_DESTROY);
> >
> >                 err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
> >                 if (err)
> > @@ -612,18 +613,18 @@ static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
> >                 }
> >         }
> >
> > -       msg->len = len;
> > +       msg->len = cpu_to_virtio16(vrp->vdev, len);
> >         msg->flags = 0;
> > -       msg->src = src;
> > -       msg->dst = dst;
> > +       msg->src = cpu_to_virtio32(vrp->vdev, src);
> > +       msg->dst = cpu_to_virtio32(vrp->vdev, dst);
> >         msg->reserved = 0;
> >         memcpy(msg->data, data, len);
> >
> >         dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
> > -               msg->src, msg->dst, msg->len, msg->flags, msg->reserved);
> > +               src, dst, len, msg->flags, msg->reserved);
> >  #if defined(CONFIG_DYNAMIC_DEBUG)
> >         dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
> > -                        msg, sizeof(*msg) + msg->len, true);
> > +                        msg, sizeof(*msg) + len, true);
> >  #endif
> >
> >         rpmsg_sg_init(&sg, msg, sizeof(*msg) + len);
> > @@ -704,13 +705,17 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
> >  {
> >         struct rpmsg_endpoint *ept;
> >         struct scatterlist sg;
> > +       unsigned int msg_len = virtio16_to_cpu(vrp->vdev, msg->len);
> >         int err;
> >
> >         dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
> > -               msg->src, msg->dst, msg->len, msg->flags, msg->reserved);
> > +               virtio32_to_cpu(vrp->vdev, msg->src),
> > +               virtio32_to_cpu(vrp->vdev, msg->dst), msg_len,
> > +               virtio16_to_cpu(vrp->vdev, msg->flags),
> > +               virtio32_to_cpu(vrp->vdev, msg->reserved));
> >  #if defined(CONFIG_DYNAMIC_DEBUG)
> >         dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
> > -                        msg, sizeof(*msg) + msg->len, true);
> > +                        msg, sizeof(*msg) + msg_len, true);
> >  #endif
> >
> >         /*
> > @@ -718,15 +723,15 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
> >          * the reported payload length.
> >          */
> >         if (len > vrp->buf_size ||
> > -           msg->len > (len - sizeof(struct rpmsg_hdr))) {
> > -               dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len);
> > +           msg_len > (len - sizeof(struct rpmsg_hdr))) {
> > +               dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg_len);
> >                 return -EINVAL;
> >         }
> >
> >         /* use the dst addr to fetch the callback of the appropriate user */
> >         mutex_lock(&vrp->endpoints_lock);
> >
> > -       ept = idr_find(&vrp->endpoints, msg->dst);
> > +       ept = idr_find(&vrp->endpoints, virtio32_to_cpu(vrp->vdev, msg->dst));
> >
> >         /* let's make sure no one deallocates ept while we use it */
> >         if (ept)
> > @@ -739,8 +744,8 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
> >                 mutex_lock(&ept->cb_lock);
> >
> >                 if (ept->cb)
> > -                       ept->cb(ept->rpdev, msg->data, msg->len, ept->priv,
> > -                               msg->src);
> > +                       ept->cb(ept->rpdev, msg->data, msg_len, ept->priv,
> > +                               virtio32_to_cpu(vrp->vdev, msg->src));
> >
> >                 mutex_unlock(&ept->cb_lock);
> >
> > @@ -846,15 +851,15 @@ static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
> >         /* don't trust the remote processor for null terminating the name */
> >         msg->name[RPMSG_NAME_SIZE - 1] = '\0';
> >
> > -       dev_info(dev, "%sing channel %s addr 0x%x\n",
> > -                msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat",
> > -                msg->name, msg->addr);
> > -
> >         strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
> >         chinfo.src = RPMSG_ADDR_ANY;
> > -       chinfo.dst = msg->addr;
> > +       chinfo.dst = virtio32_to_cpu(vrp->vdev, msg->addr);
> > +
> > +       dev_info(dev, "%sing channel %s addr 0x%x\n",
> > +                virtio32_to_cpu(vrp->vdev, msg->flags) & RPMSG_NS_DESTROY ?
> > +                "destroy" : "creat", msg->name, chinfo.dst);
> >
> > -       if (msg->flags & RPMSG_NS_DESTROY) {
> > +       if (virtio32_to_cpu(vrp->vdev, msg->flags) & RPMSG_NS_DESTROY) {
> >                 ret = rpmsg_unregister_device(&vrp->vdev->dev, &chinfo);
> >                 if (ret)
> >                         dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
> > --
> > 2.27.0
> >