On October 12, 2021 3:43 PM, Gerd Hoffmann wrote: > Hi, > > > +; Load the GDT and set the CR0. > > +; > > +; Modified: EAX, EBX, CR0, CR4, DS, ES, FS, GS, SS, CS ; > > +ReloadFlat32: > > + > > + cli > > + mov ebx, ADDR_OF(gdtr) > > + lgdt [ebx] > > No need to modify ebx here, eax should do fine. You're right. It will be updated in next version. > > > + mov eax, SEC_DEFAULT_CR0 > > + mov cr0, eax > > + > > + jmp LINEAR_CODE_SEL:dword ADDR_OF(jumpToFlat32BitAndLandHere) > > + > > +jumpToFlat32BitAndLandHere: > > Strictly speaking this is not correct, you are already in Flat32 mode, so > this only > loads cs. TDX: https://software.intel.com/content/dam/develop/external/us/en/documents/tdx-module-1.0-public-spec-v0.931.pdf In [TDX] Section 10.1.3 CR0 and CR4 are initialized when Tdx guest is created. So initialization of CR0 and CR4 are not needed. It will be updated in next version. > > > +InitTdx: > > + ; > > + ; Save EBX in EBP because EBX will be changed in ReloadFlat32 > > + ; > > + mov ebp, ebx > > See above, there is no need to modify ebx in ReloadFlat32. > Also: seems ebx is never restored ... In [TDX] Section 10.1.2 EBX[5:0] contains the GPAW. Since EBX is not changed in ReloadFlat32, *mov ebp, ebx* is not needed. It will be removed in next version. >
Thanks! Min -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#81854): https://edk2.groups.io/g/devel/message/81854 Mute This Topic: https://groups.io/mt/86253728/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
