On Thu, Jul 07, 2016 at 06:27:26PM +0800, Wanpeng Li wrote: > In addition, I see xen's vcpu_runstate_info::state is updated during > schedule, so I think I can do this similarly through kvm preemption > notifier. IIUC, xen hypervisor has VCPUOP_get_runstate_info hypercall > implemention, so the desired interface can be implemented if they add > hypercall callsite in domU. I can add hypercall to kvm similarly. So I suspect Xen has the page its writing to pinned in memory; so that a write to it is guaranteed to not fault. Otherwise I cannot see this working. That is part of the larger surgery required for KVM steal time to get 'fixed'. Currently that steal time stuff uses kvm_write_guest_cached() which appears to be able to fault in guest pages. Or I'm not reading this stuff right; which is entirely possible. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
