On September 25, 2021 11:21 AM, Brijesh Singh wrote: > Hi Min, > > > On 9/24/21 7:03 PM, Xu, Min M wrote: > > On September 24, 2021 6:58 PM, Brijesh Singh wrote: > >> Hi Min, > >> > >> On 9/21/21 4:05 AM, Min Xu wrote: > >>> ; > >>> ; Modified: EAX, EBX, ECX, EDX > >>> ; > >>> SetCr3ForPageTables64: > >>> - > >>> - ; Clear the WorkArea header. The SEV probe routines will populate the > >>> - ; work area when detected. > >>> - mov byte[WORK_AREA_GUEST_TYPE], 0 > >> Why you are removing the above block ? The workarea hdr must be > >> initialized to zero, its not safe to assume that the guest memory is > >> zero'ed in the non- encrypted case. > >> > > Hi, Brijesh > > Please see below explanation (It is in the commit message) > > - In Main16 entry point, after TransitionFromReal16To32BitFlat, > > WORK_AREA_GUEST_TYPE is cleared to 0. WORK_AREA_GUEST_TYPE was > > previously cleared in SetCr3ForPageTables64 (see commit ab77b60). > > This doesn't work after TDX is introduced in Ovmf. It is because all > > TDX CPUs (BSP and APs) start to run from 0xfffffff0. In previous code > > WORK_AREA_GUEST_TYPE will be cleared multi-times in TDX guest. So for > > SEV and Legacy guest it is moved to Main16 entry point (after > > TransitionFromReal16To32BitFlat). For TDX guest > WORK_AREA_GUEST_TYPE > > is cleared and set in InitTdxWorkarea > > thanks for clarifying it. > > This is very busy commit and making several changes at once, so some of > important common code movement is getting lost. Maybe I recommend you to > please break it into multiple. e,g this particular change can be very easily > broken > into two commits > > 1) Since TDX support need the change in the boot flow, and you are no longer > using the Main.asm from the UefiCpuPkg. This can be a pre-patch in which you > copy UefiCpuPkg/ResetVector/Vtf0/main.asm -> > OvmfPkg/ResetVector/Main.asm and document reason behind the move. > > 2) Remove clearing of workarea from SetCr3ForPageTables64 to Main.asm > > Now that we have override for the Main.asm, I think clearing of the workarea > should be done for all architecture (Ia32, x64) to cover the cases where > someone builds the OVMF for 32bit or IA32 and X64. > Thanks for reminder. I have updated the patch-set as you mentioned. But I am waiting for a conclusion of the Metadata, a unified metadata or two separate metadata.
Hoffmann and Jiewen Do we have a conclusion? Thanks Min -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#81131): https://edk2.groups.io/g/devel/message/81131 Mute This Topic: https://groups.io/mt/85761661/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
