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Re: [qemu-s390x] [PATCH v2 5/5] s390x/cpumodel: Set up CPU model for AP
From: |
Cornelia Huck |
Subject: |
Re: [qemu-s390x] [PATCH v2 5/5] s390x/cpumodel: Set up CPU model for AP device support |
Date: |
Wed, 28 Feb 2018 12:40:58 +0100 |
On Wed, 28 Feb 2018 11:26:30 +0100
David Hildenbrand <address@hidden> wrote:
> Then I request the following change in KVM:
>
> If KVM_S390_VM_CPU_FEAT_AP is enabled in KVM, ECA.28 is _always_ set
> (not just if an AP device is configured). This especially makes things a
> lot easier when it comes to handling hotplugged CPUs and avoiding race
> conditions when enabling these bits as mentioned in the KVM series.
>
> KVM_S390_VM_CPU_FEAT_AP == AP instructions available for the guest
> (don't throw an operation exception).
>
> So this feature then really is guest ABI. The instructions are
> available. If there is no device configured, bad luck.
Sounds sensible from my POV.
Re: [qemu-s390x] [Qemu-devel] [PATCH v2 0/5] s390x: vfio-ap: guest dedicated crypto adapters, no-reply, 2018/02/27