Re: [PATCH] tools/xenstore: set maximum number of grants needed

[Wei Liu <wl@xxxxxxx>]

On Thu, Sep 24, 2020 at 04:36:48PM +0200, Juergen Gross wrote:
> When running as a stubdom Xenstore should set the maximum number of
> grants needed via a call of xengnttab_set_max_grants(), as otherwise
> the number of domains which can be supported will be 128 only (the
> default number of grants supported by Mini-OS).
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
> This is a backport candidate IMO.
> ---
>  tools/xenstore/xenstored_domain.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/xenstore/xenstored_domain.c 
> b/tools/xenstore/xenstored_domain.c
> index 06359503f0..f740aa02f5 100644
> --- a/tools/xenstore/xenstored_domain.c
> +++ b/tools/xenstore/xenstored_domain.c
> @@ -630,6 +630,8 @@ void domain_init(void)
>       *xgt_handle = xengnttab_open(NULL, 0);
>       if (*xgt_handle == NULL)
>               barf_perror("Failed to open connection to gnttab");
> +     /* Allow max number of domains for mappings. */
> +     xengnttab_set_max_grants(*xgt_handle, DOMID_FIRST_RESERVED);

Why DOMID_FIRST_RESERVED as the count argument? Is the expectation here
xenstored maps one grant per domain?

Wei.

>  
>       talloc_set_destructor(xgt_handle, close_xgt_handle);
>  
> -- 
> 2.26.2
>