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 | 48 ++++++++++++++++++++++++++++------------ 1 files changed, 33 insertions(+), 15 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index bb48345..2f5ef29 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -340,7 +340,8 @@ 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 virtio_console_header header; @@ -359,15 +360,21 @@ static ssize_t send_buf(struct port *port, const char *in_buf, size_t in_count) while (in_offset < in_count) { copy_size = min(in_count - in_offset + header_len, buf->size); copy_size -= header_len; - /* - * 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 + header_len, in_buf + in_offset, copy_size); - - buf->len = header_len + copy_size; + if (from_user) { + ret = copy_from_user(buf->buf + header_len, + in_buf + in_offset, copy_size); + } 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 + header_len, + in_buf + in_offset, copy_size); + ret = 0; /* Emulate copy_from_user behaviour */ + } + buf->len = header_len + copy_size - ret; if (header_len) memcpy(buf->buf, &header, header_len); @@ -394,7 +401,8 @@ 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 buffers 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 out_offset, ret; @@ -409,9 +417,19 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) if (copy_size > buf->len - buf->offset) copy_size = buf->len - buf->offset; - memcpy(out_buf + out_offset, buf->buf + buf->offset, copy_size); + if (to_user) { + ret = copy_to_user(out_buf + out_offset, + buf->buf + buf->offset, + copy_size); + } else { + memcpy(out_buf + out_offset, + buf->buf + buf->offset, + copy_size); + ret = 0; /* Emulate copy_to_user behaviour */ + } - ret = copy_size; + /* Return the number of bytes actually copied */ + ret = copy_size - ret; buf->offset += ret; out_offset += ret; out_count -= ret; @@ -447,7 +465,7 @@ 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); } /* @@ -468,7 +486,7 @@ 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
