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From: marc.zyngier@arm•com (Marc Zyngier)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] arm64/kvm: Add generic v8 KVM target
Date: Wed, 24 Jun 2015 09:29:56 +0100	[thread overview]
Message-ID: <558A6A84.5020603@arm.com> (raw)
In-Reply-To: <CAFEAcA92uymQ3LjPQnuFiwvjSgc+jY54VrfK_Sh4v1DJ+=OPpw@mail.gmail.com>

On 22/06/15 09:44, Peter Maydell wrote:
> On 17 June 2015 at 10:00, Suzuki K. Poulose <suzuki.poulose@arm•com> wrote:
>> From: "Suzuki K. Poulose" <suzuki.poulose@arm•com>
>>
>> This patch adds a generic ARM v8 KVM target cpu type for use
>> by the new CPUs which eventualy ends up using the common sys_reg
>> table. For backward compatibility the existing targets have been
>> preserved. Any new target CPU that can be covered by generic v8
>> sys_reg tables should make use of the new generic target.
> 
> How do you intend this to work for cross-host migration?

It is not meant to work for cross migration at all.

> Is the idea that the kernel guarantees that "generic" looks
> 100% the same to the guest regardless of host hardware? I'm
> not sure that can be made to work, given impdef differences
> in ID register values, bp/wp registers, and so on.
> 
> Given that, it seems to me that we still need to provide
> KVM_ARM_TARGET_$THISCPU defines so userspace can request
> a specific guest CPU flavour; so what does this patch
> provide that isn't already provided by just having userspace
> query for the "preferred" CPU type as it does already?

The way I see this working is that a "generic" CPU cannot be migrated
(because we don't know anything about it). If it can be identified as a
known (non generic) implementation, then we can migrate it.

	M.
-- 
Jazz is not dead. It just smells funny...

  parent reply	other threads:[~2015-06-24  8:29 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-17  9:00 [PATCH] arm64/kvm: Add generic v8 KVM target Suzuki K. Poulose
2015-06-19 20:31 ` Timur Tabi
2015-06-22  6:47   ` Marc Zyngier
2015-06-22  8:44 ` Peter Maydell
2015-06-23 12:39   ` Christoffer Dall
2015-06-23 14:03     ` Suzuki K. Poulose
2015-06-23 14:16       ` Peter Maydell
2015-06-24  8:29   ` Marc Zyngier [this message]
2015-06-24  8:51     ` Christoffer Dall
2015-06-24  9:32       ` Marc Zyngier
2015-06-25 12:30         ` Christoffer Dall
2015-06-25 12:40           ` Marc Zyngier
2015-06-25 13:44             ` Marc Zyngier
2015-06-25 13:49               ` Peter Maydell
2015-06-26  9:53                 ` Christoffer Dall
2015-06-29 17:13                   ` Chalamarla, Tirumalesh
2015-06-29 17:30                     ` Marc Zyngier
2015-06-29 17:38                       ` Peter Maydell
2015-06-29 17:52                         ` Marc Zyngier
2015-06-29 18:39                           ` Chalamarla, Tirumalesh
     [not found]                             ` <D805D093-CCFE-4835-853A-B2654DAA10A1@caviumnetworks.com>
2015-07-03  8:08                               ` Marc Zyngier
2015-07-03  8:12                                 ` Peter Maydell
2015-07-03  8:28                                   ` Marc Zyngier
2015-07-03  9:34                                     ` Peter Maydell
2015-07-03 10:10                                       ` Marc Zyngier
2015-07-17  9:33                                         ` Christoffer Dall
2015-07-17  9:56                                           ` Marc Zyngier
2015-07-17 10:15                                             ` Christoffer Dall
2015-07-17 10:19                                               ` Marc Zyngier
2015-07-17 17:56                                                 ` Chalamarla, Tirumalesh

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