Jason Andryuk, le jeu. 12 mars 2020 08:55:21 -0400, a ecrit:
> usb-serial has issues with xHCI controllers where data is lost in the
> VM. Inspecting the URBs in the guest, EHCI starts every 64 byte boundary
> (wMaxPacketSize) with a header. EHCI hands packets into
> usb_serial_token_in() with size 64, so these cannot cross the 64 byte
> boundary. The xHCI controller has packets of 512 bytes and the usb-serial
> will just write through the 64 byte boundary. In the guest, this means
> data bytes are interpreted as header, so data bytes don't make it out
> the serial interface.
>
> Re-work usb_serial_token_in to chunk data into 64 byte units - 2 byte
> header and 62 bytes data. The Linux driver reads wMaxPacketSize to find
> the chunk size, so we match that.
>
> Real hardware was observed to pass in 512 byte URBs (496 bytes data +
> 8 * 2 byte headers). Since usb-serial only buffers 384 bytes of data,
> usb-serial will pass in 6 64 byte blocks and 1 12 byte partial block for
> 462 bytes max.
>
> Signed-off-by: Jason Andryuk <jandr...@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thiba...@ens-lyon.org>
> ---
> hw/usb/dev-serial.c | 43 +++++++++++++++++++++++++++----------------
> 1 file changed, 27 insertions(+), 16 deletions(-)
>
> diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
> index 71fa786bd8..96b6c34202 100644
> --- a/hw/usb/dev-serial.c
> +++ b/hw/usb/dev-serial.c
> @@ -360,15 +360,16 @@ static void usb_serial_handle_control(USBDevice *dev,
> USBPacket *p,
>
> static void usb_serial_token_in(USBSerialState *s, USBPacket *p)
> {
> - int first_len, len;
> + const int max_packet_size = desc_iface0.eps[0].wMaxPacketSize;
> + int packet_len;
> uint8_t header[2];
>
> - first_len = RECV_BUF - s->recv_ptr;
> - len = p->iov.size;
> - if (len <= 2) {
> + packet_len = p->iov.size;
> + if (packet_len <= 2) {
> p->status = USB_RET_NAK;
> return;
> }
> +
> header[0] = usb_get_modem_lines(s) | 1;
> /* We do not have the uart details */
> /* handle serial break */
> @@ -380,21 +381,31 @@ static void usb_serial_token_in(USBSerialState *s,
> USBPacket *p)
> } else {
> header[1] = 0;
> }
> - len -= 2;
> - if (len > s->recv_used)
> - len = s->recv_used;
> - if (!len) {
> +
> + if (!s->recv_used) {
> p->status = USB_RET_NAK;
> return;
> }
> - if (first_len > len)
> - first_len = len;
> - usb_packet_copy(p, header, 2);
> - usb_packet_copy(p, s->recv_buf + s->recv_ptr, first_len);
> - if (len > first_len)
> - usb_packet_copy(p, s->recv_buf, len - first_len);
> - s->recv_used -= len;
> - s->recv_ptr = (s->recv_ptr + len) % RECV_BUF;
> +
> + while (s->recv_used && packet_len > 2) {
> + int first_len, len;
> +
> + len = MIN(packet_len, max_packet_size);
> + len -= 2;
> + if (len > s->recv_used)
> + len = s->recv_used;
> +
> + first_len = RECV_BUF - s->recv_ptr;
> + if (first_len > len)
> + first_len = len;
> + usb_packet_copy(p, header, 2);
> + usb_packet_copy(p, s->recv_buf + s->recv_ptr, first_len);
> + if (len > first_len)
> + usb_packet_copy(p, s->recv_buf, len - first_len);
> + s->recv_used -= len;
> + s->recv_ptr = (s->recv_ptr + len) % RECV_BUF;
> + packet_len -= len + 2;
> + }
>
> return;
> }
> --
> 2.24.1
>
--
Samuel
We are Pentium of Borg. Division is futile. You will be approximated.
(seen in someone's .signature)
