On Thu, Feb 26, 2009 at 7:57 AM, Piavlo <piavka@xxxxxxxxxxxx> wrote: > What is still unclear to me is that's the actual difference between PV > drivers implementation in paravirtual > linux guest and PV dirvers in HVM linux guest? AFAIK in xen guest the PV > front-end drivers are quite simple, and in KVM guest > to use PV drivers the guest linux needs to be compiled with paravirtual > guest and viritio drivers support. So in both cases the OS is modified - > but there is the actual difference? first of all, using paravirtual drivers isn't considered 'core' OS modification. usually they're compiled in the Linux kernel, but could be loaded as modules. and in Windows case, they're always loaded modules. PV guests OTOH, is a very (very) inner-core modification (but a conceptually simple one, the requirements used to be documented in a single HTML for early Xen systems) now, in KVM (and possibly HVM Xen) the virtio drivers are presented via a special PCI device, while on fully PV guests, there's some function calls that can be used to communicate with the hypervisor. so, there might be some very low-level differences, but above that, they should be the same. as for performance, i really don't think it makes any perceptible difference. -- Javier -- 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
