Re: [Xen-devel] [PATCH-for-4.13 v5] Rationalize max_grant_frames and max_maptrack_frames handling

["Durrant, Paul" <pdurrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: 29 November 2019 10:46
> To: Durrant, Paul <pdurrant@xxxxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>; Anthony PERARD
> <anthony.perard@xxxxxxxxxx>; George Dunlap <george.dunlap@xxxxxxxxxx>;
> Roger Pau Monné <roger.pau@xxxxxxxxxx>; Volodymyr Babchuk
> <Volodymyr_Babchuk@xxxxxxxx>; George Dunlap <George.Dunlap@xxxxxxxxxxxxx>;
> Ian Jackson <ian.jackson@xxxxxxxxxxxxx>; Marek Marczykowski-Górecki
> <marmarek@xxxxxxxxxxxxxxxxxxxxxx>; Stefano Stabellini
> <sstabellini@xxxxxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx; Konrad Rzeszutek
> Wilk <konrad.wilk@xxxxxxxxxx>; Julien Grall <julien@xxxxxxx>; Wei Liu
> <wl@xxxxxxx>
> Subject: Re: [PATCH-for-4.13 v5] Rationalize max_grant_frames and
> max_maptrack_frames handling
> 
> On 29.11.2019 11:39, Durrant, Paul wrote:
> >> -----Original Message-----
> >> From: Jan Beulich <jbeulich@xxxxxxxx>
> >> Sent: 29 November 2019 10:29
> >> To: Durrant, Paul <pdurrant@xxxxxxxxxx>
> >> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>; Anthony PERARD
> >> <anthony.perard@xxxxxxxxxx>; George Dunlap <george.dunlap@xxxxxxxxxx>;
> >> Roger Pau Monné <roger.pau@xxxxxxxxxx>; Volodymyr Babchuk
> >> <Volodymyr_Babchuk@xxxxxxxx>; George Dunlap
> <George.Dunlap@xxxxxxxxxxxxx>;
> >> Ian Jackson <ian.jackson@xxxxxxxxxxxxx>; Marek Marczykowski-Górecki
> >> <marmarek@xxxxxxxxxxxxxxxxxxxxxx>; Stefano Stabellini
> >> <sstabellini@xxxxxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx; Konrad
> Rzeszutek
> >> Wilk <konrad.wilk@xxxxxxxxxx>; Julien Grall <julien@xxxxxxx>; Wei Liu
> >> <wl@xxxxxxx>
> >> Subject: Re: [PATCH-for-4.13 v5] Rationalize max_grant_frames and
> >> max_maptrack_frames handling
> >>
> >> On 29.11.2019 11:22, Jan Beulich wrote:
> >>> On 28.11.2019 17:52, Paul Durrant wrote:
> >>>> --- a/xen/common/grant_table.c
> >>>> +++ b/xen/common/grant_table.c
> >>>> @@ -84,11 +84,40 @@ struct grant_table {
> >>>>      struct grant_table_arch arch;
> >>>>  };
> >>>>
> >>>> +static int parse_gnttab_limit(const char *param, const char *arg,
> >>>> +                              unsigned int *valp)
> >>>> +{
> >>>> +    const char *e;
> >>>> +    unsigned long val;
> >>>> +
> >>>> +    val = simple_strtoul(arg, &e, 0);
> >>>> +    if ( *e )
> >>>> +        return -EINVAL;
> >>>> +
> >>>> +    if ( val > INT_MAX )
> >>>> +        return -ERANGE;
> >>>> +
> >>>> +    return 0;
> >>>> +}
> >>>
> >>> *valp doesn't get written to anymore.
> >
> > That was intentional, given Juergen's comment...
> >
> >> With this fixed (and no new
> >>> issues introduced ;-) ) hypervisor side
> >>> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
> >>
> >> And I guess I should have clarified: I'd be fine adding the missing
> >> assignment while committing, provided the tools side won't require
> >> any changes.
> >
> > ...but if we want to allow dom0 to set itself up for INT_MAX frames
> > in the event of a bad value then I'm not objecting.
> 
> Looks like you're misunderstanding, or I'm missing something:
> The command line options right now won't take any effect, as
> the opt_* global variables won't be written to at all. I'm not
> taking about falling back to using INT_MAX when we've noticed
> an out of bounds value.

Oh, sorry... too deep with my cutting. Yes, of course there should be a '*valp 
= val' just above 'return 0'.

  Paul

> 
> Jan
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel