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 <amit.shah@xxxxxxxxxx>
---
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
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/virtualization
