Re: [Qemu-devel] [PATCH] input: limit kbd queue depth

[Markus Armbruster <armbru@redhat.com>]

Gerd Hoffmann <kraxel@redhat.com> writes:

> Apply a limit to the number of items we accept into the keyboard queue.
>
> Impact: Without this limit vnc clients can exhaust host memory by
> sending keyboard events faster than qemu feeds them to the guest.
>
> Cc: P J P <ppandit@redhat.com>
> Cc: Huawei PSIRT <PSIRT@huawei.com>
> Reported-by: jiangxin1@huawei.com
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  ui/input.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/ui/input.c b/ui/input.c
> index ed88cda6d6..fb1f404095 100644
> --- a/ui/input.c
> +++ b/ui/input.c
> @@ -41,6 +41,8 @@ static QTAILQ_HEAD(QemuInputEventQueueHead, QemuInputEventQueue) kbd_queue =
>      QTAILQ_HEAD_INITIALIZER(kbd_queue);
>  static QEMUTimer *kbd_timer;
>  static uint32_t kbd_default_delay_ms = 10;
> +static uint32_t queue_count;
> +static uint32_t queue_limit = 1024;

Drive-by comment, feel free to ignore: I'd be tempted to lower the limit
to something comparable to actual hardware, then dumb down the queue to
an array.

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