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Re: [PATCH v2 2/2] arm64: kvm: Introduce MTE VCPU feature
From: |
Andrew Jones |
Subject: |
Re: [PATCH v2 2/2] arm64: kvm: Introduce MTE VCPU feature |
Date: |
Thu, 10 Sep 2020 13:49:43 +0200 |
On Thu, Sep 10, 2020 at 10:21:07AM +0100, Steven Price wrote:
> > We either need a KVM cap or a new CPU feature probing interface to avoid
> > making userspace try features one at a time. It's too bad that VCPU_INIT
> > doesn't clear all offending features from the feature set when returning
> > EINVAL, because then userspace could create a scratch VCPU with everything
> > it supports in order to see what KVM also supports in one go.
>
> If Peter's TELL_ME_WHAT_YOU_HAVE idea works out then perhaps we don't need
> the cap? Or would it still be useful?
>
We wouldn't need it, but we don't _need_ it now either. It's not very
convenient to probe vcpu features with scratch vcpus, especially if we
must probe one at a time, but it works. The TELL_ME_WHAT_YOU_HAVE idea
will only fix the one at a time issue, but still require a vcpu fd. If
this feature becomes a VM feature then a cap or VM level API would help
reduce the userspace probing work.
Thanks,
drew
Re: [PATCH v2 0/2] MTE support for KVM guest, Dr. David Alan Gilbert, 2020/09/07
Re: [PATCH v2 0/2] MTE support for KVM guest, Andrew Jones, 2020/09/09
Re: [PATCH v2 0/2] MTE support for KVM guest, Richard Henderson, 2020/09/09