When ports get advertised as char devices, the buffers will come from userspace. Equip the fill_readbuf function with the ability to write to userspace buffers.
Signed-off-by: Amit Shah <[email protected]> --- drivers/char/virtio_console.c | 20 ++++++++++++++------ 1 files changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 9d33239..5f61021 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -365,7 +365,8 @@ fail: * 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; unsigned long flags; @@ -374,12 +375,18 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) return 0; buf = port->inbuf; - if (out_count > buf->len - buf->offset) - out_count = buf->len - buf->offset; + out_count = min(out_count, buf->len - buf->offset); - memcpy(out_buf, buf->buf + buf->offset, out_count); + if (to_user) { + ssize_t ret; + + ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count); + if (ret) + return -EFAULT; + } else { + memcpy(out_buf, buf->buf + buf->offset, out_count); + } - /* Return the number of bytes actually copied */ buf->offset += out_count; if (buf->offset == buf->len) { @@ -395,6 +402,7 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) spin_unlock_irqrestore(&port->inbuf_lock, flags); } + /* Return the number of bytes actually copied */ return out_count; } @@ -438,7 +446,7 @@ 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
