On September 11, 2021 9:14 AM, Erdem Aktas wrote: > > On Thu, Aug 12, 2021 at 2:57 PM Min Xu <min.m...@intel.com> wrote: > > > > +; > > +; Check if it is Intel Tdx > > +; > > +; Modified: EAX, EBX, ECX, EDX > > +; > > +; If it is Intel Tdx, EAX is zero > > +; If it is not Intel Tdx, EAX is non-zero ; > > +IsTdx: > IsTdx returns 0 when TDX is enabled in CPUID but IsTdxEnabled return 1 > when TDX is enabled. Is this intentional? I will make the return result of IsTdx and IsTdxEnabled consistent. If it is Intel TDX, EAX is 1, otherwise it is 0. > > here is how IsTdxEnabled defined. > ; If TDX is enabled then EAX will be 1 > ; If TDX is disabled then EAX will be 0. > ; > IsTdxEnabled: > > > +TdxApWait: > > + cmp byte[TDX_WORK_AREA_PGTBL_READY], 0 > > + je TdxApWait > Don't we need memory fence before je TdxApWait. I did not check > what the compiler generates for this loop. Below is the code compiler generated for this loop. (VS2017/release) 106 <1> TdxApWait: 107 0000070B 803D04B0800000 <1> cmp byte[TDX_WORK_AREA_PGTBL_READY], 0 108 00000712 74F7 <1> je TdxApWait 109 00000714 EB17 <1> jmp ExitInitTdxWorkarea
This is the code lfence is added. 106 <1> TdxApWait: 107 0000070B 803D04B0800000 <1> cmp byte[TDX_WORK_AREA_PGTBL_READY], 0 108 00000712 0FAEE8 <1> lfence 109 00000715 74F4 <1> je TdxApWait 110 00000717 EB17 <1> jmp ExitInitTdxWorkarea I am not sure if lfence is needed. > Thanks! Min -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#80559): https://edk2.groups.io/g/devel/message/80559 Mute This Topic: https://groups.io/mt/84837891/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
