On 1/10/24 11:54, Gerd Hoffmann wrote: > On Wed, Jan 10, 2024 at 04:05:44PM +0800, Dun Tan wrote: >> When creating smm page table, limit maximum >> supported physical address bits returned by >> CalculateMaximumSupportAddress() to 48 if >> 5-Level Paging is disabled. >> When 5-Level Paging is disabled and the >> PhysicalAddressBits retrived from CPU HOB or >> CpuId is bigger than 48, only [0, 2^48 -1] >> range in 52-bit physical address is mapped >> in page table. > > I think this is wrong. Virtual addresses are sign-extended, > i.e. the virtual address space without 5-level paging is: > > 0x0000000000000000 -> 0x00007fffffffffff and > 0xffff800000000000 -> 0xffffffffffffffff > > Therefore identity-mapping works for [0, 2^47-1] only.
I'd have never noticed this. I'll happily defer reviewing this patch to you then! :) Thanks! Laszlo -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#113529): https://edk2.groups.io/g/devel/message/113529 Mute This Topic: https://groups.io/mt/103637402/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/9847357/21656/1706620634/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
