.snip.. > I wonder how feasible it is to map the host's vdso into the guest and > thus make the guest use the *same* (as opposed to "synchronized") clock > as the host's userspace? Another benefit is that it's essentially an > ABI so is not changed as liberally as internal structures like > timekeeper, etc. There is probably certain complication in handling the > syscall fallback in the vdso when used in the guest kernel, though. > > You'll also need to ensure neither tsc scaling and nor offsetting is > applied to the VM once this clock is enabled. This is how Xen does it - you can register the hypervisor to timestamp your vDSO regions if you want it. See xen_setup_vsyscall_time_info > > Roman.
