kvm/x86/timekeeping.rst

4 Timekeeping Virtualization for X86-Based Architectures
15    4) Virtualization Problems
21 the virtualization of this platform is the plethora of timing devices available
22 and the complexity of emulating those devices.  In addition, virtualization of
32 information relevant to KVM and hardware-based virtualization.
281 these workarounds pose unique constraints for virtualization - requiring either
351 Both VMX and SVM provide extension fields in the virtualization hardware which
383 small, may be exposed to the OS and any virtualization environment.
445 3.7. TSC virtualization - VMX
449 instructions, which is enough for full virtualization of TSC in any manner.  In
454 3.8. TSC virtualization - SVM
458 instructions, which is enough for full virtualization of TSC in any manner.  In
481 4. Virtualization Problems
484 Timekeeping is especially problematic for virtualization because a number of
498 cause similar problems to virtualization makes it a good justification for
507 or the RTC, but the problem is the same: the host virtualization engine may not
548 serialization can pose a performance issue for hardware virtualization.  An
576 and any other values derived from TSC computation (such as TSC virtualization
603 virtualization.  In theory, the effect is random and should be universally
605 causes of virtualization exits, possible context switch), this may not always
616 running under hardware virtualization due to timer interrupts being delayed or
629 require an RT aware virtualization platform.