On Thu, Aug 12, 2021 at 2:57 PM Min Xu <min.m...@intel.com> wrote: > - TdMaxVCpuNum : Get the maximum number of virutal CPUs. s/virutal/virtual
> - TdVCpuNum : Get the number of virtual CPUs. (In some case VMM may > add more vCPU in runtime). s/case/cases How is this possible considering that once the TD is finalized, there should not be any new vcpu added, right? Am I missing something here? > +++ b/MdePkg/Library/TdxLib/X64/Tdcall.nasm > @@ -0,0 +1,120 @@ > +;------------------------------------------------------------------------------ .... > +%macro tdcall_regs_preamble 2 is this even used in this file? > + ; Zero out unused (for standard TDVMCALL) registers to avoid leaking > + ; secrets to the VMM. this is for TDCALL right, there is no leaking to the tdx module. > + > + xor ebx, ebx > + xor esi, esi > + xor edi, edi > + > + xor edx, edx > + xor ebp, ebp zeroing only the lower 32bit values? why not the higher 32bit value if leaking is the concern? > +++ b/MdePkg/Library/TdxLib/X64/Tdvmcall.nasm > +%define TDVMCALL_EXPOSE_REGS_MASK 0xffec Should we expose only the minimum number of registers needed for the TDVMCALL? > > +%macro tdcall_regs_preamble 2 > + mov rax, %1 > + > + mov ecx, %2 should not we make sure that the higher 32bit of RCX is 0? RCX [63:32] are reserved and always need to be 0. > + ; R10 = 0 (standard TDVMCALL) > + > + xor r10d, r10d > + > + ; Zero out unused (for standard TDVMCALL) registers to avoid leaking > + ; secrets to the VMM. Is not rcx the bitmap of the registers that will be exposed to VMM? unused registers should be set 0 in the bitmap, why zeroing them? > + > + xor ebx, ebx > + xor esi, esi > + xor edi, edi > + xor edx, edx > + xor ebp, ebp if we are concerned about leaking some data, why xor only the lower 32bits? -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#80523): https://edk2.groups.io/g/devel/message/80523 Mute This Topic: https://groups.io/mt/84837895/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
