From: Cornelia Huck <cohuck@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
Thomas Huth <thuth@redhat.com>,
Laurent Vivier <lvivier@redhat.com>,
Eric Auger <eauger@redhat.com>,
Juan Quintela <quintela@redhat.com>,
qemu-arm@nongnu.org, qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [PATCH RFC v2 0/2] arm: enable MTE for QEMU + kvm
Date: Mon, 11 Jul 2022 17:08:59 +0200 [thread overview]
Message-ID: <87o7xv660k.fsf@redhat.com> (raw)
In-Reply-To: <YswkdVeESqf5sknQ@work-vm>
On Mon, Jul 11 2022, "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> * Cornelia Huck (cohuck@redhat.com) wrote:
>> For kvm, mte stays off by default; this is because migration is not yet
>> supported (postcopy will need an extension of the kernel interface, possibly
>> an extension of the userfaultfd interface), and turning on mte will add a
>> migration blocker.
>
> My assumption was that a normal migration would need something as well
> to retrieve and place the MTE flags; albeit not atomically.
There's KVM_ARM_MTE_COPY_TAGS, which should be sufficient to move tags
around for normal migration.
>
>> My biggest question going forward is actually concerning migration; I gather
>> that we should not bother adding something unless postcopy is working as well?
>
> I don't think that restriction is fair on you; just make sure
> postcopy_ram_supported_by_host gains an arch call and fails cleanly;
> that way if anyone tries to enable postcopy they'll find out with a
> clean fail.
Ok, if simply fencing off postcopy is fine, we can try to move forward
with what we have now. The original attempt at
https://lore.kernel.org/all/881871e8394fa18a656dfb105d42e6099335c721.1615972140.git.haibo.xu@linaro.org/
hooked itself directly into common code; maybe we should rather copy the
approach used for s390 storage keys (extra "device") instead?
next prev parent reply other threads:[~2022-07-11 15:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-07 16:16 [PATCH RFC v2 0/2] arm: enable MTE for QEMU + kvm Cornelia Huck
2022-07-07 16:16 ` [PATCH RFC v2 1/2] arm/kvm: add support for MTE Cornelia Huck
2022-07-07 16:16 ` [PATCH RFC v2 2/2] qtests/arm: add some mte tests Cornelia Huck
2022-07-09 2:59 ` [PATCH RFC v2 0/2] arm: enable MTE for QEMU + kvm Richard Henderson
2022-07-11 13:24 ` Dr. David Alan Gilbert
2022-07-11 13:39 ` Peter Maydell
2022-07-11 14:26 ` Dr. David Alan Gilbert
2022-07-11 14:56 ` Cornelia Huck
2022-07-11 15:30 ` Dr. David Alan Gilbert
2022-07-11 13:55 ` Dr. David Alan Gilbert
2022-07-11 15:08 ` Cornelia Huck [this message]
2022-07-11 15:28 ` Dr. David Alan Gilbert
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