From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>,
Claudio Fontana <cfontana@suse.de>
Cc: "Philippe Mathieu-Daudé" <f4bug@amsat.org>,
qemu-arm <qemu-arm@nongnu.org>,
qemu-devel <qemu-devel@nongnu.org>,
"Eduardo Habkost" <ehabkost@redhat.com>
Subject: Re: arm: "max" CPU class hierarchy changes possible?
Date: Thu, 11 Mar 2021 17:18:00 +0100 [thread overview]
Message-ID: <2e6a5d98-e022-0b39-5f30-92eb74491d3b@redhat.com> (raw)
In-Reply-To: <CAFEAcA8T+u6QG9PQWs40PTSZ86SEeLQrciT8WHxFyH3UVbipiA@mail.gmail.com>
On 11/03/21 16:02, Peter Maydell wrote:
> On Thu, 11 Mar 2021 at 14:27, Claudio Fontana <cfontana@suse.de> wrote:
>> the "max" cpu in x86 and s390 is a class,
>>
>> and then "host" has "max" as parent.
>>
>> This would be a convenient setup for ARM too, as it would allow to put common code between kvm and tcg in the "max" class,
>> and allow "host" to specialize the behavior for KVM (and in the future HVF probably).
>>
>> Would changing the class hierarchy this way be acceptable, cause any problems?
>
> It's not clear to me why 'host' would be a subtype of 'max':
> that doesn't seem like an obvious relationship.
On x86, "-cpu host" is essentially the same as "-cpu max" with the only
difference that it errors out on TCG. So:
- with TCG: "-cpu max" enables all that can be emulated, "-cpu host" fails
- with KVM: "-cpu max" enables all that can be virtualized, "-cpu host"
does the same
Paolo
next prev parent reply other threads:[~2021-03-11 16:28 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-11 14:27 arm: "max" CPU class hierarchy changes possible? Claudio Fontana
2021-03-11 15:02 ` Peter Maydell
2021-03-11 15:21 ` Claudio Fontana
2021-03-11 16:02 ` Peter Maydell
2021-03-11 16:18 ` Paolo Bonzini [this message]
2021-03-11 17:16 ` Claudio Fontana
2021-03-11 17:35 ` Eduardo Habkost
2021-03-11 18:33 ` Peter Maydell
2021-03-11 19:10 ` Andrew Jones
2021-03-18 11:06 ` arm_cpu_post_init (Was: Re: arm: "max" CPU class hierarchy changes possible?) Claudio Fontana
2021-03-18 11:32 ` Claudio Fontana
2021-03-18 12:08 ` Andrew Jones
2021-03-18 12:42 ` Claudio Fontana
2021-03-18 12:59 ` Andrew Jones
2021-03-18 13:10 ` Eduardo Habkost
2021-03-19 8:19 ` Claudio Fontana
2021-03-19 8:23 ` Claudio Fontana
2021-03-19 8:33 ` Claudio Fontana
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