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

[Jürgen Groß <jgross@xxxxxxxx>]

On 30.09.20 17:14, Wei Liu wrote:
> 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?
Yes. This is the theoretical maximum.


Juergen