On Fri, Sep 23, 2022 at 08:23:12AM +0200, Gerd Hoffmann wrote: > Hi, > > > > Given newer processors have more than 40 and for older ones we know > > > the possible values for the two relevant x86 vendors we could do > > > something along the lines of: > > > > > > phys-bits >= 41 -> valid > > > phys-bits == 40 + AuthenticAMD -> valid > > > phys-bits == 36,39 + GenuineIntel -> valid > > > everything else -> invalid > > > > > > Does that look sensible to you? > > > > > > > Yes, it does! Is phys-bits == 36 the same as invalid? > > 'invalid' would continue to use the current guesswork codepath for > phys-bits. Which will end up with phys-bits = 36 for smaller VMs, but > it can go beyond that in VMs with alot (32G or more) of memory. That > logic assumes that physical machines with enough RAM for 32G+ guests > have a physical address space > 64G. > > 'phys-bits = 36' would be a hard limit. > > So, it's not exactly the same but small VMs wouldn't see a difference. > > take care, > Gerd I dropped the patch for now. -- MST
