On Tue, Jan 09, 2024 at 01:29:06PM +0100, Borislav Petkov wrote: > At least three issues I see with that: > > - the allocation can fail so it is a lot more convenient when the > firmware prepares it > > - the RMP_BASE and RMP_END writes need to be verified they actially did > set up the RMP range because if they haven't, you might as well > throw SNP security out of the window. In general, letting the kernel > do the RMP allocation needs to be verified very very thoroughly. > > - a future feature might make this more complicated - What do you do if you boot on a system which has the RMP already allocated in the BIOS? - How do you detect that it is the L1 kernel that must allocate the RMP? - Why can't you use the BIOS allocated RMP in your scenario too instead of the L1 kernel allocating it? - ... I might think of more. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette