Re: [PATCH v6 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active

[Brijesh Singh]

On 09/10/2018 10:28 AM, Sean Christopherson wrote:
...

> > IIRC, during guest creation time qemu will check the host supported
> > VCPUS count. If count is greater than KVM_MAX_VCPUS then it will
> > fail to launch guest (or fail to hot plug vcpus). In other words, the
> > number of vcpus in a KVM guest will never to > KVM_MAX_VCPUS.
> >
> > Am I missing something ?
>
> KVM_MAX_VCPUS is a definition for use in the *host*, it's even defined
> in kvm_host.h. ÂThe guest's pvclock code won't get magically recompiled
> if KVM_MAX_VCPUS is changed in the host. ÂKVM_MAX_VCPUS is an arbitrary
> value in the sense that there isn't a fundamental hard limit, i.e. the
> value can be changed, either for a custom KVM build or in mainline,
> e.g. it was bumped in 2016:

Ah I see your point. thanks for clarifying it.