From: Sarah Newman <srn@prgmr.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Julien Grall <julien.grall@arm.com>,
Jan Beulich <JBeulich@suse.com>
Cc: "Lars Kurth" <lars.kurth@citrix.com>,
StefanoStabellini <sstabellini@kernel.org>,
"Wei Liu" <wl@xen.org>,
"George Dunlap" <George.Dunlap@eu.citrix.com>,
Xen-devel <xen-devel@lists.xenproject.org>,
"Ian Jackson" <ian.jackson@citrix.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] Terminology for "guest" - Was: [PATCH] docs/sphinx: Introduction
Date: Mon, 12 Aug 2019 19:59:03 -0700 [thread overview]
Message-ID: <760ba819-a3ab-c5dc-054c-3064c6b07a1b@prgmr.com> (raw)
In-Reply-To: <b436f483-1f80-c91b-8c17-a1cfbf98b6f1@citrix.com>
On 8/12/19 8:01 AM, Andrew Cooper wrote:
> On 12/08/2019 15:53, George Dunlap wrote:
>> On 8/8/19 10:13 AM, Julien Grall wrote:
>>> Hi Jan,
>>>
>>> On 08/08/2019 10:04, Jan Beulich wrote:
>>>> On 08.08.2019 10:43, Andrew Cooper wrote:
>>>>> On 08/08/2019 07:22, Jan Beulich wrote:
>>>>>> On 07.08.2019 21:41, Andrew Cooper wrote:
>>>>>>> --- /dev/null
>>>>>>> +++ b/docs/glossary.rst
>>>>>>> @@ -0,0 +1,37 @@
>>>>>>> +Glossary
>>>>>>> +========
>>>>>>> +
>>>>>>> +.. Terms should appear in alphabetical order
>>>>>>> +
>>>>>>> +.. glossary::
>>>>>>> +
>>>>>>> + control domain
>>>>>>> + A :term:`domain`, commonly dom0, with the permission and
>>>>>>> responsibility
>>>>>>> + to create and manage other domains on the system.
>>>>>>> +
>>>>>>> + domain
>>>>>>> + A domain is Xen's unit of resource ownership, and generally has
>>>>>>> at the
>>>>>>> + minimum some RAM and virtual CPUs.
>>>>>>> +
>>>>>>> + The terms :term:`domain` and :term:`guest` are commonly used
>>>>>>> + interchangeably, but they mean subtly different things.
>>>>>>> +
>>>>>>> + A guest is a single virtual machine.
>>>>>>> +
>>>>>>> + Consider the case of live migration where, for a period of
>>>>>>> time, one
>>>>>>> + guest will be comprised of two domains, while it is in transit.
>>>>>>> +
>>>>>>> + domid
>>>>>>> + The numeric identifier of a running :term:`domain`. It is
>>>>>>> unique to a
>>>>>>> + single instance of Xen, used as the identifier in various APIs,
>>>>>>> and is
>>>>>>> + typically allocated sequentially from 0.
>>>>>>> +
>>>>>>> + guest
>>>>>>> + See :term:`domain`
>>>>>> I think you want to mention the usual distinction here: Dom0 is,
>>>>>> while a domain, commonly not considered a guest.
>>>>> To be honest, I had totally forgotten about that. I guess now is the
>>>>> proper time to rehash it in public.
>>>>>
>>>>> I don't think the way it currently gets used has a clear or coherent set
>>>>> of rules, because I can't think of any to describe how it does get used.
>>>>>
>>>>> Either there are a clear and coherent (and simple!) set of rules for
>>>>> what we mean by "guest", at which point they can live here in the
>>>>> glossary, or the fuzzy way it is current used should cease.
>>>> What's fuzzy about Dom0 not being a guest (due to being a part of the
>>>> host instead)?
>>> Dom0 is not part of the host if you are using an hardware domain. I
>>> actually thought we renamed everything in Xen from Dom0 to hwdom to
>>> avoid the confusion.
>>>
>>> I also would rather avoid to treat "dom0" as not a guest. In normal
>>> setup this is a more privilege guest, in other setup this may just be a
>>> normal guest (think about partitioning).
>> A literal guest is someone who doesn't live in the building (or work in
>> the buliding, if you're in a hotel). The fact that the staff cleaning
>> rooms are restricted in their privileges doesn't make them guests of the
>> hotel.
>>
>> The toolstack domain, the hardware domain, the driver domain, the
>> xenstore domain, and so on are all part of the host system, designed to
>> allow you to use Xen to do the thing you actually want to do: Run guests.
>>
>> And it's important that we have a word that distinguishes "domains that
>> we only care about because they make it possible to run other domains",
>> and "domains that we actually want to run". "guest / host" is a natural
>> terminology for these.
>>
>> We already have the word "domain", which includes dom0, driver domains,
>> toolstack domains, hardware domains, as well as guest domains. We don't
>> need "guest" to be a synonym for "domain".
>
> So...
>
> Please can someone propose wording simple, clear wording for what
> "guest" means.
A potentially untrusted domain.
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next prev parent reply other threads:[~2019-08-13 2:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 19:41 [Xen-devel] [PATCH] docs/sphinx: Introduction Andrew Cooper
2019-08-07 22:49 ` Hans van Kranenburg
2019-08-07 23:25 ` Andrew Cooper
2019-08-08 6:22 ` Jan Beulich
2019-08-08 8:43 ` [Xen-devel] Terminology for "guest" - Was: " Andrew Cooper
2019-08-08 9:04 ` Jan Beulich
2019-08-08 9:13 ` Julien Grall
2019-08-08 10:30 ` Andrew Cooper
2019-08-08 10:49 ` Jan Beulich
2019-08-08 11:22 ` Rich Persaud
2019-08-12 14:53 ` George Dunlap
2019-08-12 15:01 ` Andrew Cooper
2019-08-13 2:59 ` Sarah Newman [this message]
2019-08-13 8:43 ` George Dunlap
2019-08-13 8:46 ` Lars Kurth
2019-08-13 19:58 ` Sarah Newman
2019-08-08 9:49 ` Roger Pau Monné
2019-08-12 15:36 ` [Xen-devel] " George Dunlap
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