Jeremy Fitzhardinge <[EMAIL PROTECTED]> writes: > Eric W. Biederman wrote: >> Note. I don't believe we use either trampoline (cpu startup or acpi wakeup) >> in the hypervisor case (esp Xen). So we should be able to completely ignore >> Xen and do the memcpy of pgd entries. >> > > Indeed. The alias mapping can be set up in native_pagetable_setup_done() and > needn't involve Xen at all.
Good. Then this case gets easy. We just need a pgd that has pgd entries that duplicate the kernel pgd entries at both address 0 and at the normal kernel address. In 64bit mode we make this part of the trampoline because we need a pgt below 4G so that we can point a 32bit %cr3 value at it. We can either use that technique for the 32bit kernel (and be consistent) or we can have a single trampoline/wakeup pgd that we use. As all pgd entries must be below 4G in 32bit mode. Although if we really wanted to be restrictive we could have a much more limited set of identity page table entries that only map the low 1M, or possibly just 640K. Eric -- 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/
