Re: [Xen-devel] [PATCH v3 3/3] tools: introduce parameter max_wp_ram_ranges.

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Feb 01, 2016 at 12:52:51AM -0700, Jan Beulich wrote:
> >>> On 30.01.16 at 15:38, <yu.c.zhang@xxxxxxxxxxxxxxx> wrote:
> 
> > On 1/30/2016 12:33 AM, Jan Beulich wrote:
> >>>>> On 29.01.16 at 11:45, <yu.c.zhang@xxxxxxxxxxxxxxx> wrote:
> >>> --- a/xen/arch/x86/hvm/hvm.c
> >>> +++ b/xen/arch/x86/hvm/hvm.c
> >>> @@ -940,6 +940,8 @@ static int hvm_ioreq_server_alloc_rangesets(struct 
> >>> hvm_ioreq_server *s,
> >>>   {
> >>>       unsigned int i;
> >>>       int rc;
> >>> +    unsigned int max_wp_ram_ranges =
> >>> +        s->domain->arch.hvm_domain.params[HVM_PARAM_MAX_WP_RAM_RANGES];
> >>
> >> You're still losing the upper 32 bits here. Iirc you agreed to range
> >> check the value before storing into params[]...
> > 
> > Thanks, Jan. :)
> > In this version, the check is added in routine parse_config_data().
> > If option 'max_wp_ram_ranges' is configured with an unreasonable value,
> > the xl will terminate, before calling xc_hvm_param_set(). Does this
> > change meet your requirement? Or maybe did I have some misunderstanding
> > on this issue?
> 
> Checking in the tools is desirable, but the hypervisor shouldn't rely
> on any tool side checking.
> 

As in hypervisor needs to sanitise all input from toolstack? I don't
think Xen does that today.

What is the difference between this particular configuration option and
all other options in the same hvm_set_conf_params function?

Wei.

> Jan
> 

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