[libvirt] [PATCH 2/5] Introduce SMM feature

[Laszlo Ersek]

On 08/02/16 10:58, Michal Privoznik wrote:
> On 01.08.2016 21:10, Laszlo Ersek wrote:
>> On 08/01/16 19:05, Gerd Hoffmann wrote:
>>>   Hi,
>>>
>>>> If it does, then the host kernel should be 4.4 or later. (If we want to
>>>> capture version numbers, then for each minor release, the latest patch
>>>> level should be required: 4.4.16, 4.5.7, 4.6.5, 4.7.0, because there
>>>> have been a number of KVM tweaks and stable backports for SMM support.)
>>>
>>> Better check /dev/kvm for the KVM_CAP_X86_SMM capability, otherwise the
>>> rhel-7 kernel is out even though smm is backported.
>>>
>>> Probably libvirt already has checks for other caps so it should be easy.
>>
>> The problem is that KVM_CAP_X86_SMM does not guarantee that all the
>> tricky bugfixes are present in the host kernel.
>>
>>
> 
> Moreover, libvirt does not validate nor check guest kernel. And the only
> /dev/kvm/ caps we check are:
> 
> KVM_CAP_IOMMU - to see if legacy PCI passthrough works
> 
> KVM_CAP_PPC_SMT -
> KVM_CAP_MAX_VCPUS -
> KVM_CAP_NR_VCPUS  - for some vCPUs counts
> 
> I don't think libvirt should check for KVM_CAP_x86_SMM. I mean, if we go
> down the rabbit hole, libvirt would have to check everything. The buck
> has to stop somewhere.

I agree.

Thanks
Laszlo