On Fri, Sep 12, 2025, Tom Lendacky wrote: > On 9/12/25 13:34, Sean Christopherson wrote: > > But the below build failures show that they aren't dead code, which means that > > kernels with CONFIG_KVM_AMD_SEV=n will silently (until something explodes) do the > > wrong thing, because the stubs are hiding the missing dependencies. > > > > arch/x86/boot/startup/sev-shared.c: In function ‘pvalidate_4k_page’: > > arch/x86/boot/startup/sev-shared.c:820:17: error: implicit declaration of function ‘sev_evict_cache’ [-Wimplicit-function-declaration] > > 820 | sev_evict_cache((void *)vaddr, 1); > > Yeah, this one is on me. sev_evict_cache() is guest code and should be > under the CONFIG_AMD_MEM_ENCRYPT #ifdef. > > > | ^~~~~~~~~~~~~~~ > > AR arch/x86/realmode/built-in.a > > arch/x86/coco/sev/core.c: In function ‘pvalidate_pages’: > > arch/x86/coco/sev/core.c:386:25: error: implicit declaration of function ‘sev_evict_cache’ [-Wimplicit-function-declaration] > > 386 | sev_evict_cache(pfn_to_kaddr(e->gfn), e->pagesize ? 512 : 1); > > | ^~~~~~~~~~~~~~~ > > arch/x86/mm/mem_encrypt.c: In function ‘mem_encrypt_setup_arch’: > > arch/x86/mm/mem_encrypt.c:112:17: error: implicit declaration of function ‘snp_fixup_e820_tables’ [-Wimplicit-function-declaration] > > 112 | snp_fixup_e820_tables(); > > This function is only meant to be used if we're going to run SEV guests, > so being guarded by CONFIG_KVM_AMD_SEV was on purpose. I'm just not sure > why the stub didn't get used... or did you remove them? I removed all the stubs to see what would break (I was expecting nothing since all of KVM's accesses are gated by CONFIG_KVM_AMD_SEV).
