[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v6 5/6] arm/dom0less: assign dom0less guests to cpupools
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Luca Fancellu <Luca.Fancellu@xxxxxxx>
- Date: Fri, 8 Apr 2022 11:15:33 +0000
- Accept-language: en-GB, en-US
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=+83DT/uAtdMxoQzYy0KHyrfyw7jZqiTUrnK7IvFHIbM=; b=ljPj/ZBszVJ4zLzbEpF3TdM8OVqSgOvraz9IMU4CcoJJ/eeDDDnI86S3EtOYnmz79xbLgL58ng3+nF72wvxoUquesppLp6rxFADlcF6zY1/mWrokOaJR4sDz2PbprQzmE6dX/1jCkD7YN+PWtnp2I/h+20Mg8IGwpxcJRvnArlFqSA+Ft+t7dB37xeHnDdYOFhMO5aQJW6YP0W2iKWgjyhd3MgclJjLNu4KUUOAVK+AktqXKQuY3YtOjGC26/fuVcUQ6ncrXW7IJc0sBXXAZE1Vo5JFZmbH7zWUnPH5w5RjkATc+4rvWgUWFG4xTTc/a6H3ZjWbclNG8V9b3Oieilg==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=JnLMPAYyztF9jSp0JFykN+DulAzCEZIr01ynTeMvMMdSJnMVilNQwU7xolG+1ydf6wqx3IJa5oidW6NDIAjxCNY5mfGLFZBP26Ao8w9byStfAWlu6t7QqiWhX6qqCaT/juK8DefLtJ/e1OXpUsY/8cjo30GFsibZvsisqe0NA+T1QgYrvmxV92oCQRUoosUHViZaxeRBxLBE22IfcYbmmrZoB1zoSDNTAJ/iwKEo8v5uQU859K0+37Nd/WCskQXOTZbJcP0UdscHINJ/JC/jDibakmAo0zOvjdAfR+ZypfUXMid95Eehpk6erkBfULtd9pPTQgpzH6RPh0TwzqpTWA==
- Authentication-results-original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com;
- Cc: Juergen Gross <jgross@xxxxxxxx>, Bertrand Marquis <Bertrand.Marquis@xxxxxxx>, Wei Chen <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>, Wei Liu <wl@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- Delivery-date: Fri, 08 Apr 2022 11:16:18 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Nodisclaimer: true
- Original-authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com;
- Thread-index: AQHYSyUS0CLVSvR2nk+ITbzc2Ry0wKzlusgAgAAH7oCAAAy5gIAADjGA
- Thread-topic: [PATCH v6 5/6] arm/dom0less: assign dom0less guests to cpupools
> On 8 Apr 2022, at 11:24, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>
> On 08.04.2022 11:39, Luca Fancellu wrote:
>>
>>
>>> On 8 Apr 2022, at 10:10, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>>
>>> On 08.04.2022 10:45, Luca Fancellu wrote:
>>>> @@ -106,6 +106,8 @@ struct xen_domctl_createdomain {
>>>> /* Per-vCPU buffer size in bytes. 0 to disable. */
>>>> uint32_t vmtrace_size;
>>>>
>>>> + uint32_t cpupool_id;
>>>
>>> This could do with a comment explaining default behavior. In particular
>>> I wonder what 0 means: Looking at cpupool_destroy() I can't see that it
>>> would be impossible to delete pool 0 (but there may of course be
>>> reasons elsewhere, e.g. preventing pool 0 to ever go empty) - Jürgen?
>>> Yet if pool 0 can be removed, zero being passed in here should imo not
>>> lead to failure of VM creation. Otoh I understand that this would
>>> already happen ahead of your change, preventing of which would
>>> apparently possible only via passing CPUPOOLID_NONE here.
>>
>> Pool-0 can’t be emptied because Dom0 is sitting there (the patch is modifying
>> cpupool_id only for DomUs).
>
> But we're talking about dom0less as per the subject of the patch here.
Domains started using dom0less feature are not privileged and can’t do any
operation
on cpu pools, that’s why I thought about Dom0.
>
>> I thought the name was self explanatory, but if I have to put a comment,
>> would
>> It work something like that:
>>
>> /* Cpupool id where the domain will be assigned on creation */
>
> I don't view this kind of comment as necessary. I was really after
> calling out default behavior, along the lines of "0 to disable" that
> you can see in patch context.
Ok, could this work?
/* Domain cpupool id on creation. Default 0 as Pool-0 is always present. */
>
> Jan
|
