On 3/21/22 01:51, Oliver Upton wrote:
Right now we have guestTSCOffset as a vCPU attribute, we have guestTOD
returned by KVM_GET_CLOCK, and we plan to have hostTSCFreq in sysfs. It's a
bit mix-and-match, but it's already a 5-tuple that the destination can use.
What's missing is a ioctl on the destination side that relieves userspace
from having to do the math.
That ioctl will work fine, but userspace needs to accept all the
nastiness that ensues. If it yanks the guest too hard into the future
it'll need to pick up the pieces when the guest kernel panics.
It can do that before issuing the ioctl, by comparing the source and
destination TOD, can't it?
Paolo
