[libvirt] Exporting kvm_max_guest_tsc_khz to userspace (was Re: [PATCH 4/4] kvm: Allow migration with invtsc)

> > > > > Maybe your use case just needs a explicit "invtsc-migration=on" > > > command-line flag without a mechanism to abort migration on > > > mismatch? I can't tell. > > > > Again, there is no special case. > > > > > Note that even if we follow your suggestion and implement an > > > alternative version of patch 4/4 to cover your use case, I will > > > strongly recommend libvirt developers to support configuring TSC > > > frequency if they want to support invtsc + migration without > > > surprising/unpredictable restrictions on migratability. > > > > Well, alright. If you make the TSC frequency of the host > > available to mgmt software as you describe, and write the steps mgmt > > software should take, i'm good. > > I plan to. The problem is that the mechanism to query the host > frequency may be unavailable in the first version. Well just export KVM_GET_TSC_KHZ in a QMP command right? Its pretty easy. Let me know if you need any help coding or testing.