Re: [PATCH v20210601 05/38] tools: add xc_is_known_page_type to libxenctrl

[Juergen Gross <jgross@xxxxxxxx>]

On 01.06.21 18:10, Olaf Hering wrote:
> Users of xc_get_pfn_type_batch may want to sanity check the data
> returned by Xen. Add a simple helper for this purpose.
>
> Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
> ---
>   tools/libs/ctrl/xc_private.h | 33 +++++++++++++++++++++++++++++++++
>   1 file changed, 33 insertions(+)
>
> diff --git a/tools/libs/ctrl/xc_private.h b/tools/libs/ctrl/xc_private.h
> index 5d2c7274fb..afb08aafe1 100644
> --- a/tools/libs/ctrl/xc_private.h
> +++ b/tools/libs/ctrl/xc_private.h
> @@ -421,6 +421,39 @@ void *xc_map_foreign_ranges(xc_interface *xch, uint32_t 
> dom,
>   int xc_get_pfn_type_batch(xc_interface *xch, uint32_t dom,
>                             unsigned int num, xen_pfn_t *);
>   
> +/* Sanitiy check for types returned by Xen */
> +static inline bool xc_is_known_page_type(xen_pfn_t type)
> +{
> +    bool ret;
> +
> +    switch (type)
I think you should not imply the planned use case here. It would be
better to use "switch (type & XEN_DOMCTL_PFINFO_LTAB_MASK)".

I'm on the edge regarding putting the new function into xc_private.h.
In the end your use case is _not_ to call the new function from
libxenctrl.


Juergen

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