On Mon, 2013-05-20 at 12:25 +0300, Gleb Natapov wrote: > On Mon, May 20, 2013 at 10:56:22AM +0200, Paolo Bonzini wrote: > > In any case, this patch needs more comments and a better commit message. > > Microsoft docs are decent, but there are several non-obvious points in > > how the patches were done, and they need to be documented. > I wish you were right about Microsoft docs :) So in Hyper-V spec they > say: > > Special value of 0xFFFFFFFF is used to indicate that this facility is no > longer a reliable source of reference time and the virtual machine must > fall back to a different source (for example, the virtual PM timer). > > May be they really mean "virtual PM timer" here and reference counter is > not considered as a fall back source, but this is not what we want. As far as I know, you cannot fall back from iTSC to PMTimer or HPET, but you can fallback to reference counters. > > On the other hand in API specification [1] they have: > > #define HV_REFERENCE_TSC_SEQUENCE_INVALID (0x00000000) > > which is not even documented in hyper-v spec. Actually 0 is specified as > valid value there. Go figure. > > [1] http://msdn.microsoft.com/en-us/library/windows/hardware/ff540244%28v=vs.85%29.aspx > > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
