On 17/03/2017 11:56, Borislav Petkov wrote: >> Theoretically or practically? > In the sense, it needs to be tried first to see how ugly it can get. > >> It only looks at the E820 map, doesn't it? Why does it have to do >> anything with percpu memory areas? > That's irrelevant. What we want to do is take what's in init_mm.pgd and > modify it. And use the facilities in arch/x86/mm/init_{32,64}.c because > they already know about early/late pagetable pages allocation and they > deal with the kernel pagetable anyway. If it is possible to do it in a fairly hypervisor-independent manner, I'm all for it. That is, only by looking at AMD-specified CPUID leaves and at kernel ELF sections. Paolo > And *not* teach pageattr.c about memblock because that can be misused, > as tglx pointed out on IRC.