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Re: [PATCH 1/5] common: don't (kind of) open-code rcu_lock_domain_by_any_id()
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
- Date: Wed, 13 Jan 2021 22:42:52 +0000
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On 05/01/2021 14:17, Jan Beulich wrote:
>>> ---
>>> Besides get_pg_owner(), gnttab_copy_lock_domain() has similar strange(?)
>>> behavior: They accept DOMID_SELF, but not the resolved ID of the caller.
>> I queried that behaviour years and years ago.
>>
>> According to Keir, it is part of the attempt to force guests to not know
>> their own domid. Xen itself does (or did) its very hardest to prevent a
>> domU knowing its own domid, while at the same time the "domid" key in
>> xenstore is mandatory for setting up PV rings.
>>
>> I'd personally think was a short sighted move.
> Let me make another patch then, unless you can see reasons we should
> stick to the current behavior. Figuring out its own domid is possible
> for a domain, after all, and even shouldn't be overly difficult.
I don't see any reason to keep these semantics, other than the general
argument against relaxing things vs compatibility with older hypervisors.
I honestly can't make up my mind, so whichever you prefer.
~Andrew
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