On Sun, Dec 2, 2012 at 4:38 PM, Matthew Hicks <[email protected]> wrote:
> This is a bad idea. You want to make the processor fully > virtualizable. This requires the ability for a hypervisor to > interpose on an unmodified operating system. For this to work, the > hypervisor changes the operating system privilege to 0 (user mode) and > when the operating system accesses or modifies privileged state, an > exception triggers and the hypervisor takes over. With your proposal, > the hypervisor would never know and the system would collapse. > Shouldn't the hypervisor be implemented with another SR bit, or another SPR altogether? Eg, a HM (hypervisor mode) bit? I don't see how pushing the OS into userspace would work. How can the OS protect user processes from accessing each other's memory, for instance? -Pete
_______________________________________________ OpenRISC mailing list [email protected] http://lists.openrisc.net/listinfo/openrisc
