Re: [PATCH v2 18/23] KVM: selftests: Generalize nested mapping functions

[Sean Christopherson]

On Tue, Oct 21, 2025, Yosry Ahmed wrote:
> Instead of passing in a pointer to struct vmx_pages, pass in the GPA of
> the root of the EPTs, as that's the only member being used. Furthermore,
> only use ept_pte_masks for VMX, and use x86_pte_masks otherwise (which
> is what NPT uses).
> 
> This is in preparation of supporting NPTs as well.
> 
> No functional change intended.
> 
> Signed-off-by: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
> ---
>  tools/testing/selftests/kvm/include/x86/vmx.h |  6 +++---
>  .../testing/selftests/kvm/lib/x86/memstress.c |  4 ++--
>  tools/testing/selftests/kvm/lib/x86/vmx.c     | 20 ++++++++++---------
>  .../selftests/kvm/x86/vmx_dirty_log_test.c    |  6 +++---
>  4 files changed, 19 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/x86/vmx.h b/tools/testing/selftests/kvm/include/x86/vmx.h
> index 5aa14ceed050a..4429e83e1f52c 100644
> --- a/tools/testing/selftests/kvm/include/x86/vmx.h
> +++ b/tools/testing/selftests/kvm/include/x86/vmx.h
> @@ -561,11 +561,11 @@ bool load_vmcs(struct vmx_pages *vmx);
>  
>  bool ept_1g_pages_supported(void);
>  
> -void nested_map(struct vmx_pages *vmx, struct kvm_vm *vm,
> +void nested_map(struct kvm_vm *vm, vm_paddr_t root_gpa,
>  		 uint64_t nested_paddr, uint64_t paddr, uint64_t size);
> -void nested_map_memslot(struct vmx_pages *vmx, struct kvm_vm *vm,
> +void nested_map_memslot(struct kvm_vm *vm, vm_paddr_t root_gpa,
>  			uint32_t memslot);
> -void nested_identity_map_1g(struct vmx_pages *vmx, struct kvm_vm *vm,
> +void nested_identity_map_1g(struct kvm_vm *vm, vm_paddr_t root_gpa,
>  			    uint64_t addr, uint64_t size);

Ugh, "nested" is a bad namespace.  Running L2 doesn't strictly require nested
TDP, and the operations themselves are non-nested, in the sense that we're
modifying stage-2 / TDP page tables.

My vote would be to do a rename to either stage2_pg_map() or tdp_pg_map()