Hi
On Tue, May 11, 2021 at 1:04 PM Gerd Hoffmann <[email protected]> wrote:
> > > +/* ------------------------------------------------------------------
> */
> > > +/* send messages
> */
> > > +
> > > +static void vdagent_send_buf(VDAgentChardev *vd, void *ptr, uint32_t
> > > msgsize)
> > > +{
> > > + uint8_t *msgbuf = ptr;
> > > + uint32_t len, pos = 0;
> > > +
> > > + while (pos < msgsize) {
> > > + len = qemu_chr_be_can_write(CHARDEV(vd));
> > > + if (len > msgsize - pos) {
> > > + len = msgsize - pos;
> > > + }
> > > + qemu_chr_be_write(CHARDEV(vd), msgbuf + pos, len);
> > > + pos += len;
> > > + }
> > >
> >
> > This looks like it could easily busy loop. Have you thought about fixing
> > this?
>
> Incremental fix [ to be squashed ]
>
>
thanks, a few comments below
take care,
> Gerd
>
> diff --git a/ui/vdagent.c b/ui/vdagent.c
> index 64213aa25a06..efa98725fb22 100644
> --- a/ui/vdagent.c
> +++ b/ui/vdagent.c
> @@ -3,7 +3,9 @@
> #include "include/qemu-common.h"
> #include "chardev/char.h"
> #include "hw/qdev-core.h"
> +#include "qemu/buffer.h"
> #include "qemu/option.h"
> +#include "qemu/units.h"
> #include "ui/clipboard.h"
> #include "ui/console.h"
> #include "ui/input.h"
> @@ -16,6 +18,7 @@
>
> #define VDAGENT_MOUSE_DEFAULT true
> #define VDAGENT_CLIPBOARD_DEFAULT false
> +#define VDAGENT_BUFFER_LIMIT (1 * MiB)
>
> struct VDAgentChardev {
> Chardev parent;
> @@ -32,6 +35,7 @@ struct VDAgentChardev {
> uint32_t msgsize;
> uint8_t *xbuf;
> uint32_t xoff, xsize;
> + Buffer outbuf;
>
> /* mouse */
> DeviceState mouse_dev;
> @@ -124,18 +128,20 @@ static const char *type_name[] = {
> /* ------------------------------------------------------------------ */
> /* send messages */
>
> -static void vdagent_send_buf(VDAgentChardev *vd, void *ptr, uint32_t
> msgsize)
> +static void vdagent_send_buf(VDAgentChardev *vd)
> {
> - uint8_t *msgbuf = ptr;
> - uint32_t len, pos = 0;
> + uint32_t len;
>
> - while (pos < msgsize) {
> + while (!buffer_empty(&vd->outbuf)) {
> len = qemu_chr_be_can_write(CHARDEV(vd));
> - if (len > msgsize - pos) {
> - len = msgsize - pos;
> + if (len == 0) {
> + return;
> }
> - qemu_chr_be_write(CHARDEV(vd), msgbuf + pos, len);
> - pos += len;
> + if (len > vd->outbuf.offset) {
> + len = vd->outbuf.offset;
> + }
> + qemu_chr_be_write(CHARDEV(vd), vd->outbuf.buffer, len);
> + buffer_advance(&vd->outbuf, len);
> }
> }
>
> @@ -150,16 +156,22 @@ static void vdagent_send_msg(VDAgentChardev *vd,
> VDAgentMessage *msg)
>
> msg->protocol = VD_AGENT_PROTOCOL;
>
> + if (vd->outbuf.offset + msgsize > VDAGENT_BUFFER_LIMIT) {
> + return;
> + }
>
Silently dropping messages, there might be some bad consequences. At least
I think we should error_report(). Eventually, the caller should be informed
too.
> +
> while (msgoff < msgsize) {
> chunk.port = VDP_CLIENT_PORT;
> chunk.size = msgsize - msgoff;
> if (chunk.size > 1024) {
> chunk.size = 1024;
> }
> - vdagent_send_buf(vd, &chunk, sizeof(chunk));
> - vdagent_send_buf(vd, msgbuf + msgoff, chunk.size);
> + buffer_reserve(&vd->outbuf, sizeof(chunk) + chunk.size);
> + buffer_append(&vd->outbuf, &chunk, sizeof(chunk));
> + buffer_append(&vd->outbuf, msgbuf + msgoff, chunk.size);
> msgoff += chunk.size;
> }
> + vdagent_send_buf(vd);
> }
>
> static void vdagent_send_caps(VDAgentChardev *vd)
> @@ -550,6 +562,7 @@ static void vdagent_chr_open(Chardev *chr,
>
> &vdagent_mouse_handler);
> }
>
> + buffer_init(&vd->outbuf, "vdagent-outbuf");
>
Needs a buffer_free(). Move it to object init/finalize ?
*be_opened = true;
> }
>
> @@ -702,6 +715,13 @@ static int vdagent_chr_write(Chardev *chr, const
> uint8_t *buf, int len)
> return ret;
> }
>
> +static void vdagent_chr_accept_input(Chardev *chr)
> +{
> + VDAgentChardev *vd = QEMU_VDAGENT_CHARDEV(chr);
> +
> + vdagent_send_buf(vd);
> +}
> +
> static void vdagent_chr_set_fe_open(struct Chardev *chr, int fe_open)
> {
> VDAgentChardev *vd = QEMU_VDAGENT_CHARDEV(chr);
> @@ -748,6 +768,7 @@ static void vdagent_chr_class_init(ObjectClass *oc,
> void *data)
> cc->open = vdagent_chr_open;
> cc->chr_write = vdagent_chr_write;
> cc->chr_set_fe_open = vdagent_chr_set_fe_open;
> + cc->chr_accept_input = vdagent_chr_accept_input;
> }
>
> static const TypeInfo vdagent_chr_type_info = {
> --
> 2.31.1
>
>
--
Marc-André Lureau
