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From: Julien Grall <julien.grall@linaro.org>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	George Dunlap <george.dunlap@eu.citrix.com>,
	Andre Przywara <andre.przywara@arm.com>, Tim Deegan <tim@xen.org>,
	Jan Beulich <JBeulich@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [RFC] xen/arm: Handling cache maintenance instructions by set/way
Date: Wed, 6 Dec 2017 15:19:25 +0000	[thread overview]
Message-ID: <7b646782-9cfd-9f55-3ce3-c132dceb61be@linaro.org> (raw)
In-Reply-To: <20171206151010.GG28074@char.us.oracle.com>

Hi Konrad,

On 12/06/2017 03:10 PM, Konrad Rzeszutek Wilk wrote:
> .snip..
>> The suggested policy is based on the KVM one:
>> 	- If we trap a S/W instructions, we enable VM trapping (e.g HCR_EL2.TVM) to
>> detect cache being turned on/off, and do a full clean.
>> 	- We flush the caches on both caches being turned on and off.
>> 	- Once the caches are enabled, we stop trapping VM instructions.
>>
>> Doing a full clean will require to go through the P2M and flush the entries
>> one by one. At the moment, all the memory is mapped. As you can imagine
>> flushing guest with hundreds of MB will take a very long time (Linux timeout
>> during CPU bring).
> 
> Yikes. Since you mention 'based on the KVM one' - did they solve this particular
> problem or do they also have the same issue?

KVM is using populate on demand by default.

Cheers,

-- 
Julien Grall

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  reply	other threads:[~2017-12-06 15:19 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-05 18:39 [RFC] xen/arm: Handling cache maintenance instructions by set/way Julien Grall
2017-12-05 22:35 ` Stefano Stabellini
2017-12-05 22:54   ` Julien Grall
2017-12-06  9:15 ` Jan Beulich
2017-12-06 12:10   ` Julien Grall
2017-12-06 12:28 ` George Dunlap
2017-12-06 12:58   ` Julien Grall
2017-12-06 13:01     ` Julien Grall
2017-12-06 15:15     ` Jan Beulich
2017-12-06 17:52       ` Julien Grall
2017-12-07  9:39         ` Jan Beulich
2017-12-07 15:22           ` Julien Grall
2017-12-07 15:49             ` Jan Beulich
2017-12-06 17:49     ` George Dunlap
2017-12-07 13:52       ` Julien Grall
2017-12-07 14:25         ` Jan Beulich
2017-12-07 14:53         ` Marc Zyngier
2017-12-07 15:45           ` Jan Beulich
2017-12-07 16:04             ` Marc Zyngier
2017-12-07 16:04             ` Julien Grall
2017-12-07 16:44               ` George Dunlap
2017-12-07 16:58                 ` Marc Zyngier
2017-12-07 18:06                   ` George Dunlap
2017-12-07 19:21                     ` Marc Zyngier
2017-12-08 10:56                       ` George Dunlap
2017-12-11 11:10                         ` Andre Przywara
2017-12-11 12:15                           ` George Dunlap
2017-12-11 21:11                           ` Julien Grall
2017-12-08  8:03     ` Tim Deegan
2017-12-08 14:38       ` Julien Grall
2017-12-10 15:22         ` Tim Deegan
2017-12-11 19:50           ` Julien Grall
2017-12-11 10:06         ` Jan Beulich
2017-12-11 11:11           ` Andrew Cooper
2017-12-11 11:58             ` Jan Beulich
2017-12-11 20:26           ` Julien Grall
2017-12-12  7:52             ` Jan Beulich
2017-12-06 15:10 ` Konrad Rzeszutek Wilk
2017-12-06 15:19   ` Julien Grall [this message]
2017-12-06 15:24     ` George Dunlap
2017-12-06 15:26       ` Julien Grall

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