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Re: [Qemu-devel] [PATCH 3/7] KVM: i386: Add support for KVM_CAP_EXCEPTIO
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 3/7] KVM: i386: Add support for KVM_CAP_EXCEPTION_PAYLOAD |
Date: |
Mon, 17 Jun 2019 19:27:40 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 |
On 17/06/19 13:34, Liran Alon wrote:
> Putting this all together, in case kernel doesn’t support extracting
> nested-state, there is no decent way to know if guest is running
> nested-virtualization. Which means that in theory we always need to
> fail migration in case kernel doesn’t support KVM_CAP_NESTED_STATE or
> KVM_CAP_EXCEPTION_PAYLOAD and vCPU is exposed with VMX/SVM
> capability.
For VMX this would be okay because we had a blocker before this series,
and this wouldn't be any worse.
For SVM we can ignore the case and fix it when we have
KVM_CAP_NESTED_STATE, as again that wouldn't be any worse.
Paolo
> I can condition this behaviour with a flag that can be manipulated
> using QMP to allow user to indicate it wishes to migrate guest anyway
> in this case. This however bring me back to the entire discussion I
> had with Dr. David Alan Gilbert on migration backwards compatibility
> in general and the fact that I believe we should have a generic QMP
> command which allows to provide list of VMState subsections that can
> be ignored in migration… See:
> https://www.mail-archive.com/address@hidden/msg622274.html
>
> Paolo, What are your thoughts on how I would proceed with this?
[Qemu-devel] [PATCH 7/7] Revert "target/i386: kvm: add VMX migration blocker", Paolo Bonzini, 2019/06/14
[Qemu-devel] [PATCH 6/7] KVM: i386: Add support for save and restore nested state, Paolo Bonzini, 2019/06/14
[Qemu-devel] [PATCH 4/7] linux-headers: import improved definition of KVM_GET/SET_NESTED_STATE structs, Paolo Bonzini, 2019/06/14