Re: [PATCH v2 6/7] KVM: x86/mmu: Rename kvm_mmu->get_cr3() to ->get_guest_cr3_or_eptp()

[Paolo Bonzini]

On 07/02/20 18:37, Sean Christopherson wrote:
> Rename kvm_mmu->get_cr3() to call out that it is retrieving a guest
> value, as opposed to kvm_mmu->set_cr3(), which sets a host value, and to
> note that it will return L1's EPTP when nested EPT is in use.  Hopefully
> the new name will also make it more obvious that L1's nested_cr3 is
> returned in SVM's nested NPT case.
> 
> No functional change intended.

Should we call it "get_pgd", since that is how Linux calls the top-level
directory?  I always get confused by PUD/PMD, but as long as we only
keep one /p.d/ moniker it should be fine.

Paolo

> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
>  arch/x86/include/asm/kvm_host.h |  2 +-
>  arch/x86/kvm/mmu/mmu.c          | 24 ++++++++++++------------
>  arch/x86/kvm/mmu/paging_tmpl.h  |  2 +-
>  arch/x86/kvm/svm.c              | 10 +++++-----
>  arch/x86/kvm/vmx/nested.c       |  8 ++++----
>  arch/x86/kvm/x86.c              |  2 +-
>  6 files changed, 24 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 4dffbc10d3f8..d3d69ad2e969 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -383,7 +383,7 @@ struct kvm_mmu_root_info {
>   */
>  struct kvm_mmu {
>  	void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long root);
> -	unsigned long (*get_cr3)(struct kvm_vcpu *vcpu);
> +	unsigned long (*get_guest_cr3_or_eptp)(struct kvm_vcpu *vcpu);
>  	u64 (*get_pdptr)(struct kvm_vcpu *vcpu, int index);
>  	int (*page_fault)(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u32 err,
>  			  bool prefault);
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 70f67bcab7db..13df4b4a5649 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -3731,7 +3731,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
>  		vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root);
>  	} else
>  		BUG();
> -	vcpu->arch.mmu->root_cr3 = vcpu->arch.mmu->get_cr3(vcpu);
> +	vcpu->arch.mmu->root_cr3 = vcpu->arch.mmu->get_guest_cr3_or_eptp(vcpu);
>  
>  	return 0;
>  }
> @@ -3743,7 +3743,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
>  	gfn_t root_gfn, root_cr3;
>  	int i;
>  
> -	root_cr3 = vcpu->arch.mmu->get_cr3(vcpu);
> +	root_cr3 = vcpu->arch.mmu->get_guest_cr3_or_eptp(vcpu);
>  	root_gfn = root_cr3 >> PAGE_SHIFT;
>  
>  	if (mmu_check_root(vcpu, root_gfn))
> @@ -4080,7 +4080,7 @@ static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
>  	arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
>  	arch.gfn = gfn;
>  	arch.direct_map = vcpu->arch.mmu->direct_map;
> -	arch.cr3 = vcpu->arch.mmu->get_cr3(vcpu);
> +	arch.cr3 = vcpu->arch.mmu->get_guest_cr3_or_eptp(vcpu);
>  
>  	return kvm_setup_async_pf(vcpu, cr2_or_gpa,
>  				  kvm_vcpu_gfn_to_hva(vcpu, gfn), &arch);
> @@ -4932,7 +4932,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
>  	context->shadow_root_level = kvm_x86_ops->get_tdp_level(vcpu);
>  	context->direct_map = true;
>  	context->set_cr3 = kvm_x86_ops->set_tdp_cr3;
> -	context->get_cr3 = get_cr3;
> +	context->get_guest_cr3_or_eptp = get_cr3;
>  	context->get_pdptr = kvm_pdptr_read;
>  	context->inject_page_fault = kvm_inject_page_fault;
>  
> @@ -5080,10 +5080,10 @@ static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
>  	struct kvm_mmu *context = vcpu->arch.mmu;
>  
>  	kvm_init_shadow_mmu(vcpu);
> -	context->set_cr3           = kvm_x86_ops->set_cr3;
> -	context->get_cr3           = get_cr3;
> -	context->get_pdptr         = kvm_pdptr_read;
> -	context->inject_page_fault = kvm_inject_page_fault;
> +	context->set_cr3	       = kvm_x86_ops->set_cr3;
> +	context->get_guest_cr3_or_eptp = get_cr3;
> +	context->get_pdptr	       = kvm_pdptr_read;
> +	context->inject_page_fault     = kvm_inject_page_fault;
>  }
>  
>  static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
> @@ -5095,10 +5095,10 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
>  	if (new_role.as_u64 == g_context->mmu_role.as_u64)
>  		return;
>  
> -	g_context->mmu_role.as_u64 = new_role.as_u64;
> -	g_context->get_cr3           = get_cr3;
> -	g_context->get_pdptr         = kvm_pdptr_read;
> -	g_context->inject_page_fault = kvm_inject_page_fault;
> +	g_context->mmu_role.as_u64	 = new_role.as_u64;
> +	g_context->get_guest_cr3_or_eptp = get_cr3;
> +	g_context->get_pdptr		 = kvm_pdptr_read;
> +	g_context->inject_page_fault	 = kvm_inject_page_fault;
>  
>  	/*
>  	 * Note that arch.mmu->gva_to_gpa translates l2_gpa to l1_gpa using
> diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
> index 6b15b58f3ecc..24dfa0fcba56 100644
> --- a/arch/x86/kvm/mmu/paging_tmpl.h
> +++ b/arch/x86/kvm/mmu/paging_tmpl.h
> @@ -333,7 +333,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
>  	trace_kvm_mmu_pagetable_walk(addr, access);
>  retry_walk:
>  	walker->level = mmu->root_level;
> -	pte           = mmu->get_cr3(vcpu);
> +	pte           = mmu->get_guest_cr3_or_eptp(vcpu);
>  	have_ad       = PT_HAVE_ACCESSED_DIRTY(mmu);
>  
>  #if PTTYPE == 64
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index a3e32d61d60c..1e2f05a79417 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -3026,11 +3026,11 @@ static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
>  
>  	vcpu->arch.mmu = &vcpu->arch.guest_mmu;
>  	kvm_init_shadow_mmu(vcpu);
> -	vcpu->arch.mmu->set_cr3           = nested_svm_set_tdp_cr3;
> -	vcpu->arch.mmu->get_cr3           = nested_svm_get_tdp_cr3;
> -	vcpu->arch.mmu->get_pdptr         = nested_svm_get_tdp_pdptr;
> -	vcpu->arch.mmu->inject_page_fault = nested_svm_inject_npf_exit;
> -	vcpu->arch.mmu->shadow_root_level = get_npt_level(vcpu);
> +	vcpu->arch.mmu->set_cr3		      = nested_svm_set_tdp_cr3;
> +	vcpu->arch.mmu->get_guest_cr3_or_eptp = nested_svm_get_tdp_cr3;
> +	vcpu->arch.mmu->get_pdptr	      = nested_svm_get_tdp_pdptr;
> +	vcpu->arch.mmu->inject_page_fault     = nested_svm_inject_npf_exit;
> +	vcpu->arch.mmu->shadow_root_level     = get_npt_level(vcpu);
>  	reset_shadow_zero_bits_mask(vcpu, vcpu->arch.mmu);
>  	vcpu->arch.walk_mmu              = &vcpu->arch.nested_mmu;
>  }
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 4fb05c0e29fe..2d7b87b532f5 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -354,10 +354,10 @@ static void nested_ept_init_mmu_context(struct kvm_vcpu *vcpu)
>  			VMX_EPT_EXECUTE_ONLY_BIT,
>  			nested_ept_ad_enabled(vcpu),
>  			nested_ept_get_eptp(vcpu));
> -	vcpu->arch.mmu->set_cr3           = vmx_set_cr3;
> -	vcpu->arch.mmu->get_cr3           = nested_ept_get_eptp;
> -	vcpu->arch.mmu->inject_page_fault = nested_ept_inject_page_fault;
> -	vcpu->arch.mmu->get_pdptr         = kvm_pdptr_read;
> +	vcpu->arch.mmu->set_cr3		      = vmx_set_cr3;
> +	vcpu->arch.mmu->get_guest_cr3_or_eptp = nested_ept_get_eptp;
> +	vcpu->arch.mmu->inject_page_fault     = nested_ept_inject_page_fault;
> +	vcpu->arch.mmu->get_pdptr	      = kvm_pdptr_read;
>  
>  	vcpu->arch.walk_mmu              = &vcpu->arch.nested_mmu;
>  }
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index fbabb2f06273..1e6d8766fbdd 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -10179,7 +10179,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
>  		return;
>  
>  	if (!vcpu->arch.mmu->direct_map &&
> -	      work->arch.cr3 != vcpu->arch.mmu->get_cr3(vcpu))
> +	      work->arch.cr3 != vcpu->arch.mmu->get_guest_cr3_or_eptp(vcpu))
>  		return;
>  
>  	vcpu->arch.mmu->page_fault(vcpu, work->cr2_or_gpa, 0, true);
>