When ports get advertised as char devices, the buffers will come from userspace. Equip the send_buf and fill_readbuf functions with the ability to write to / read from userspace buffers respectively.
Signed-off-by: Amit Shah <[email protected]> --- drivers/char/virtio_console.c | 45 ++++++++++++++++++++++++++-------------- 1 files changed, 29 insertions(+), 16 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index c0bc146..35bdd41 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -332,7 +332,8 @@ static ssize_t send_control_msg(struct port *port, unsigned int event, return 0; } -static ssize_t send_buf(struct port *port, const char *in_buf, size_t in_count) +static ssize_t send_buf(struct port *port, const char *in_buf, size_t in_count, + bool from_user) { struct scatterlist sg[1]; struct virtqueue *out_vq; @@ -357,15 +358,19 @@ static ssize_t send_buf(struct port *port, const char *in_buf, size_t in_count) if (in_count > buf->size) in_count = buf->size; - /* - * Since we're not sure when the host will actually - * consume the data and tell us about it, we have to - * copy the data here in case the caller frees the - * in_buf. - */ - memcpy(buf->buf, in_buf, in_count); - - buf->len = in_count; + if (from_user) { + ret = copy_from_user(buf->buf, in_buf, in_count); + } else { + /* + * Since we're not sure when the host will actually + * consume the data and tell us about it, we have to + * copy the data here in case the caller frees the + * in_buf. + */ + memcpy(buf->buf, in_buf, in_count); + ret = 0; /* Emulate copy_from_user behaviour */ + } + buf->len = in_count - ret; sg_init_one(sg, buf->buf, buf->len); ret = out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, buf); @@ -384,9 +389,11 @@ static ssize_t send_buf(struct port *port, const char *in_buf, size_t in_count) * Give out the data that's requested from the buffer that we have * queued up. */ -static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) +static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count, + bool to_user) { struct port_buffer *buf; + ssize_t ret; unsigned long flags; if (!out_count || !port_has_data(port)) @@ -396,10 +403,16 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) if (out_count > buf->len - buf->offset) out_count = buf->len - buf->offset; - memcpy(out_buf, buf->buf + buf->offset, out_count); + if (to_user) { + ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count); + } else { + memcpy(out_buf, buf->buf + buf->offset, out_count); + ret = 0; /* Emulate copy_to_user behaviour */ + } /* Return the number of bytes actually copied */ - buf->offset += out_count; + ret = out_count - ret; + buf->offset += ret; if (buf->offset == buf->len) { /* @@ -414,7 +427,7 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) spin_unlock_irqrestore(&port->inbuf_lock, flags); } - return out_count; + return ret; } /* @@ -436,7 +449,7 @@ static int put_chars(u32 vtermno, const char *buf, int count) if (unlikely(early_put_chars)) return early_put_chars(vtermno, buf, count); - return send_buf(port, buf, count); + return send_buf(port, buf, count, false); } /* @@ -457,7 +470,7 @@ static int get_chars(u32 vtermno, char *buf, int count) /* If we don't have an input queue yet, we can't get input. */ BUG_ON(!port->in_vq); - return fill_readbuf(port, buf, count); + return fill_readbuf(port, buf, count, false); } static void resize_console(struct port *port) -- 1.6.2.5 _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
