On Tue, Nov 04, 2025 at 11:08:23AM +0000, Brendan Jackman wrote: > On Mon Nov 3, 2025 at 10:50 AM UTC, Mike Rapoport wrote: > > > >> >> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > >> >> > index 1d0585616aa3..73a15cade54a 100644 > >> >> > --- a/include/linux/kvm_host.h > >> >> > +++ b/include/linux/kvm_host.h > >> >> > @@ -731,6 +731,12 @@ static inline bool > >> >> > kvm_arch_has_private_mem(struct kvm *kvm) > >> >> > bool kvm_arch_supports_gmem_mmap(struct kvm *kvm); > >> >> > #endif > >> >> > > >> >> > +#ifdef CONFIG_KVM_GUEST_MEMFD > >> >> > +#ifndef kvm_arch_gmem_supports_no_direct_map > >> >> > +#define kvm_arch_gmem_supports_no_direct_map can_set_direct_map > >> >> > +#endif > >> >> > +#endif /* CONFIG_KVM_GUEST_MEMFD */ > >> >> > > But this is for CONFIG_ARCH_HAS_DIRECT_MAP? I am reading this as a stub > to fill in for archs that have set_direct_map_*, but don't have runtime > disablement like arm64.
You are right. > Whereas my concern is archs that don't have set_direct_map_* at all, > i.e. where we need to unconditionally fail > GUEST_MEMFG_FLAG_NO_DIRECT_MAP. > > (Or would we prefer to just not define it at all on those archs? Not > sure what the norms are there, I guess that's a question for KVM/arch > maintainers). It makes sense to define can_set_direct_map to false for arches that don't support set_direct_map. -- Sincerely yours, Mike.
