Linux: how guest VM storage is supported

Question

On Linux, I guess VMs and load another instance of Linux. VM is created through KVM / libvirt / qemu. Guest VM is considered as a kernel core process. Suppose, for some reason, the VM QEMU guest process does not start for some time .. how does the kernel in the VM support time? Suppose I have a timer in my application in a guest virtual machine. If the qemu VM guest process itself is not scheduled, will this affect the expiration of my timer?

Answer 1

Some virtualization solutions have a VM clock connected to some clock (nodes) of the host, so the VM clock does not quench independently. In other cases, such a thing cannot occur (for example, on the basis of an emulated interrupt clock), which in turn leads to a skewed clock. You can try to fight ntpd with a wall clock, but for things like CLOCK_MONOTONIC, you probably have to live with it.