On Fri, 23 Nov 2018 at 14:36, Andrew Jones <[email protected]> wrote: > > On Fri, Nov 23, 2018 at 01:14:31PM +0100, Ard Biesheuvel wrote: > > Drop the PcdPrePiCpuMemorySize definitions that limit it to 40 > > bits on AArch64 targets. This is no longer appropriate now that > > KVM has been enhanced to permit any IPA space size permitted by > > the architecture. This means the value will revert back to its > > default of 48. > > If we're running on older KVM, then, since KVM just passes through > the host value of id_aa64mmfr0_el1, firmware will see whatever > the host supports and use that (I'm not sure if the 48-bit default > ever can come into play too). In either case, it probably doesn't > matter, because just like the guest kernel works today on older > KVM, as long as nothing is placed above 40 bits there isn't any > problem. Is that the case for edk2 too? >
The value of 48 serves as a limit now, which makes sense given that 52-bit requires 64k pages, which we don't support. But as I said, it might make sense to permit the GCD space to describe that much, which is actually a nice side effect of the previous patch, which takes the value directly from the CPU system register on virt targets. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
