Re: [PATCH 09/12] kvm-all: introduce limits for name_size and num_desc

[Peter Maydell]

On Mon, 25 Sept 2023 at 20:43, Vladimir Sementsov-Ogievskiy
<vsementsov@yandex-team.ru> wrote:
>
> Coverity doesn't like when the value with unchecked bounds that comes
> from fd is used as length for IO or allocation. And really, that's not
> a good practice. Let's introduce at least an empirical limits for these
> values.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
>  accel/kvm/kvm-all.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index ff1578bb32..6d0ba7d900 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -3988,6 +3988,9 @@ typedef struct StatsDescriptors {
>  static QTAILQ_HEAD(, StatsDescriptors) stats_descriptors =
>      QTAILQ_HEAD_INITIALIZER(stats_descriptors);
>
> +
> +#define KVM_STATS_QEMU_MAX_NAME_SIZE (1024 * 1024)
> +#define KVM_STATS_QEMU_MAX_NUM_DESC (1024)

These seem arbitrary. Why these values in particular?
Does the kernel have any limitation on the values it passes us?
Do we have any particular limit on what we can handle?

thanks
-- PMM