linux-kernel - Re: [PATCH v4 11/21] KVM: selftests: Stop passing VMX metadata to TDP mapping functions

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Message-ID: <rkbap4vemw6yu52djlg7lerquuhucw3urlvbvfpekfxgnibosf@ijebzfchpulp>
Date: Fri, 2 Jan 2026 17:12:32 +0000
From: Yosry Ahmed <yosry.ahmed@...ux.dev>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>, 
	Oliver Upton <oupton@...nel.org>, Tianrui Zhao <zhaotianrui@...ngson.cn>, 
	Bibo Mao <maobibo@...ngson.cn>, Huacai Chen <chenhuacai@...nel.org>, 
	Anup Patel <anup@...infault.org>, Paul Walmsley <pjw@...nel.org>, 
	Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
	Christian Borntraeger <borntraeger@...ux.ibm.com>, Janosch Frank <frankja@...ux.ibm.com>, 
	Claudio Imbrenda <imbrenda@...ux.ibm.com>, kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, loongarch@...ts.linux.dev, kvm-riscv@...ts.infradead.org, 
	linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 11/21] KVM: selftests: Stop passing VMX metadata to
 TDP mapping functions

On Tue, Dec 30, 2025 at 03:01:40PM -0800, Sean Christopherson wrote:
> From: Yosry Ahmed <yosry.ahmed@...ux.dev>
> 
> The root GPA can now be retrieved from the nested MMU, stop passing VMX
> metadata. This is in preparation for making these functions work for
> NPTs as well.
> 
> Opportunistically drop tdp_pg_map() since it's unused.
> 
> No functional change intended.
> 
> Signed-off-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  tools/testing/selftests/kvm/include/x86/vmx.h | 11 ++-----
>  .../testing/selftests/kvm/lib/x86/memstress.c | 11 +++----
>  tools/testing/selftests/kvm/lib/x86/vmx.c     | 33 +++++++------------
>  .../selftests/kvm/x86/vmx_dirty_log_test.c    |  9 +++--
>  4 files changed, 24 insertions(+), 40 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/x86/vmx.h b/tools/testing/selftests/kvm/include/x86/vmx.h
> index 1fd83c23529a..4dd4c2094ee6 100644
> --- a/tools/testing/selftests/kvm/include/x86/vmx.h
> +++ b/tools/testing/selftests/kvm/include/x86/vmx.h
> @@ -557,14 +557,9 @@ bool load_vmcs(struct vmx_pages *vmx);
>  
>  bool ept_1g_pages_supported(void);
>  
> -void tdp_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm, uint64_t nested_paddr,
> -		uint64_t paddr);
> -void tdp_map(struct vmx_pages *vmx, struct kvm_vm *vm, uint64_t nested_paddr,
> -	     uint64_t paddr, uint64_t size);
> -void tdp_identity_map_default_memslots(struct vmx_pages *vmx,
> -				       struct kvm_vm *vm);
> -void tdp_identity_map_1g(struct vmx_pages *vmx, struct kvm_vm *vm,
> -			 uint64_t addr, uint64_t size);
> +void tdp_map(struct kvm_vm *vm, uint64_t nested_paddr, uint64_t paddr, uint64_t size);
> +void tdp_identity_map_default_memslots(struct kvm_vm *vm);
> +void tdp_identity_map_1g(struct kvm_vm *vm,  uint64_t addr, uint64_t size);
>  bool kvm_cpu_has_ept(void);
>  void vm_enable_ept(struct kvm_vm *vm);
>  void prepare_virtualize_apic_accesses(struct vmx_pages *vmx, struct kvm_vm *vm);
> diff --git a/tools/testing/selftests/kvm/lib/x86/memstress.c b/tools/testing/selftests/kvm/lib/x86/memstress.c
> index 00f7f11e5f0e..3319cb57a78d 100644
> --- a/tools/testing/selftests/kvm/lib/x86/memstress.c
> +++ b/tools/testing/selftests/kvm/lib/x86/memstress.c
> @@ -59,7 +59,7 @@ uint64_t memstress_nested_pages(int nr_vcpus)
>  	return 513 + 10 * nr_vcpus;
>  }
>  
> -static void memstress_setup_ept_mappings(struct vmx_pages *vmx, struct kvm_vm *vm)
> +static void memstress_setup_ept_mappings(struct kvm_vm *vm)
>  {
>  	uint64_t start, end;
>  
> @@ -68,16 +68,15 @@ static void memstress_setup_ept_mappings(struct vmx_pages *vmx, struct kvm_vm *v
>  	 * KVM can shadow the EPT12 with the maximum huge page size supported
>  	 * by the backing source.
>  	 */
> -	tdp_identity_map_1g(vmx, vm, 0, 0x100000000ULL);
> +	tdp_identity_map_1g(vm, 0, 0x100000000ULL);
>  
>  	start = align_down(memstress_args.gpa, PG_SIZE_1G);
>  	end = align_up(memstress_args.gpa + memstress_args.size, PG_SIZE_1G);
> -	tdp_identity_map_1g(vmx, vm, start, end - start);
> +	tdp_identity_map_1g(vm, start, end - start);
>  }
>  
>  void memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu *vcpus[])
>  {
> -	struct vmx_pages *vmx;
>  	struct kvm_regs regs;
>  	vm_vaddr_t vmx_gva;
>  	int vcpu_id;
> @@ -87,11 +86,11 @@ void memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu *vc
>  
>  	vm_enable_ept(vm);
>  	for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
> -		vmx = vcpu_alloc_vmx(vm, &vmx_gva);
> +		vcpu_alloc_vmx(vm, &vmx_gva);
>  
>  		/* The EPTs are shared across vCPUs, setup the mappings once */
>  		if (vcpu_id == 0)
> -			memstress_setup_ept_mappings(vmx, vm);
> +			memstress_setup_ept_mappings(vm);

Oh and if you're feeling nitpicky while applying, I think this call can
actually be moved outside of the loop now, right after vm_enable_ept(),
dropping the whole vcpu_id == 0 special case.

>  
>  		/*
>  		 * Override the vCPU to run memstress_l1_guest_code() which will