Zachary Amsden wrote: > On Fri, 2007-09-14 at 16:44 -0500, Anthony Liguori wrote: > > >> So then each module creates a hypercall page using this magic MSR and >> the hypervisor has to keep track of it so that it can appropriately >> change the page on migration. The page can only contain a single >> instruction or else it cannot be easily changed (or you have to be able >> to prevent the guest from being migrated while in the hypercall page). >> >> We're really talking about identical models. Instead of an MSR, the #GP >> is what tells the hypervisor to update the instruction. The nice thing >> about this is that you don't have to keep track of all the current >> hypercall page locations in the hypervisor. >> > > I agree, multiple hypercall pages is insane. I was thinking more of a > single hypercall page, fixed in place by the hypervisor, not the kernel. > > Then each module can read an MSR saying what VA the hypercall page is > at, and the hypervisor can simply flip one page to switch architectures. >
VA as in "Virtual Address"? the ppc people don't have hypervisor-visible virtual addresses, and the hypervisor (on x86) can't safely select a virtual address, and ... That means you need a physical address, so you need a central initialization routine, and drivers for unmodified OSes can no longer be self contained. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
