On Thu, Oct 10, 2019 at 7:39 PM Roman Kagan <rkagan@xxxxxxxxxxxxx> wrote: > > 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. That is what I initially wanted to do, but I couldn't find an easy way to map a host page into the guest, outside of the regular userspace (ioctl) KVM way of adding memory to a VM. -- Suleiman
