Re: [PATCH 2/5] xen/common/domctl: introduce XEN_DOMCTL_get/setdomaincontext

[Julien Grall <julien@xxxxxxx>]

On 27/03/2020 18:50, Paul Durrant wrote:
> + * XEN_DOMCTL_getdomaincontext
> + * ---------------------------
> + *
> + * buffer (IN):   The buffer into which the context data should be
> + *                copied, or NULL to query the buffer size that should
> + *                be allocated.
> + * size (IN/OUT): If 'buffer' is NULL then the value passed in must be
> + *                zero, and the value passed out will be the size of the
> + *                buffer to allocate.
> + *                If 'buffer' is non-NULL then the value passed in must
> + *                be the size of the buffer into which data may be copied.
> + * mask (IN):     See comment on domain_save/load() in xen/save.h.
> + *
> + * XEN_DOMCTL_setdomaincontext
> + * ---------------------------
> + *
> + * buffer (IN):   The buffer from which the context data should be
> + *                copied.
> + * size (IN):     The size of the buffer from which data may be copied.
> + *                This data must include DOMAIN_SAVE_CODE_HEADER at the
> + *                start and terminate with a DOMAIN_SAVE_CODE_END record.
> + *                Any data beyond the DOMAIN_SAVE_CODE_END record will be
> + *                ignored.
> + * mask (IN):     See comment on domain_save/load() in xen/save.h.
> + */
> +struct xen_domctl_domaincontext {
> +    uint32_t size;
> +    uint32_t mask;
I actually forgot to comment on the mask. We are restricting ourself to 
32 different type of records. I don't think this is going to fly very far.
But what is the expected use of 'mask'. Are we expecting the toolstack 
to say which records should be saved/restored?
Cheers,

--
Julien Grall