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Re: [PATCH v2 3/4] xen/arm: Reserve domid 0 for Dom0
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Luca Fancellu <luca.fancellu@xxxxxxx>
- Date: Thu, 8 Apr 2021 14:12:12 +0100
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- Cc: Bertrand Marquis <bertrand.marquis@xxxxxxx>, wei.chen@xxxxxxx, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Ian Jackson <iwj@xxxxxxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
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> On 8 Apr 2021, at 11:46, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>
> On 08.04.2021 11:48, Luca Fancellu wrote:
>> --- a/xen/common/domctl.c
>> +++ b/xen/common/domctl.c
>> @@ -419,7 +419,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t)
>> u_domctl)
>> {
>> if ( dom == DOMID_FIRST_RESERVED )
>> dom = 1;
>> - if ( is_free_domid(dom) )
>> + if ( (dom != 0) && is_free_domid(dom) )
>> break;
>> }
>>
>
> I don't think this change is needed - I don't see how dom could
> ever end up being zero. The code is already intended to be safe
> wrt accidentally creating a domain with ID zero. (Granted "rover"
> would benefit from being moved into the yet more narrow scope,
> which would make this even more obvious.)
Yes I agree, I will remove the check in the next version patch.
Cheers,
Luca
>
> Jan
|
