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It seems like an easy target to > make that optional, e.g. with a separate configuration item: > > --- > config AMD_UNACCEPTED_MEMORY >        def_bool y >        depends on AMD_MEM_ENCRYPT && EFI_STUB >        select UNACCEPTED_MEMORY > --- > > Using that we can successfully build and run SNP VMs without UEFI/OVMF > (which we already did with earlier Linux versions). This seems reasonable to me. I would recommend naming it AMD_MEM_ENCRYPT_UNACCEPTED_MEMORY to keep the association and add a prompt along the lines of "AMD Secure Encrypted Virtualization (SEV) unaccepted memory support" (I don't really see this used with bare-metal, but who knows.) I think there will need to be changes elsewhere in the kernel to support this, though. A quick build test with just AMD_UNACCEPTED_MEMORY not being set broke the build when EFI_STUB was still set to y. > > From a quick look at > >   [PATCHv14 9/9] x86/tdx: Add unaccepted memory support > > it actually seems very similar for INTEL_TDX_GUEST. > > Ideally UNACCEPTED_MEMORY would not assume EFI either, but the > implementation actually clearly does. @Kirill, is this something you are interested in having as well? Thanks, Tom