KVM: x86/mmu: Move nested NPT reserved bit calculation into MMU proper

Move nested NPT's invocation of reset_shadow_zero_bits_mask() into the
MMU proper and unexport said function.  Aside from dropping an export,
this is a baby step toward eliminating the call entirely by fixing the
shadow_root_level confusion.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622175739.3610207-19-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.h

@@ -68,9 +68,6 @@ static __always_inline u64 rsvd_bits(int s, int e)
 void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask);
 void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only);
 
-void
-reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
-
 void kvm_init_mmu(struct kvm_vcpu *vcpu);
 void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
 			     unsigned long cr4, u64 efer, gpa_t nested_cr3);

arch/x86/kvm/mmu/mmu.c

@@ -4212,8 +4212,8 @@ static inline u64 reserved_hpa_bits(void)
  * table in guest or amd nested guest, its mmu features completely
  * follow the features in guest.
  */
-void
-reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
+static void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
+					struct kvm_mmu *context)
 {
 	/*
 	 * KVM uses NX when TDP is disabled to handle a variety of scenarios,
@@ -4247,7 +4247,6 @@ reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
 	}
 
 }
-EXPORT_SYMBOL_GPL(reset_shadow_zero_bits_mask);
 
 static inline bool boot_cpu_is_amd(void)
 {
@@ -4714,6 +4713,12 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
 		 */
 		context->shadow_root_level = new_role.base.level;
 	}
+
+	/*
+	 * Redo the shadow bits, the reset done by shadow_mmu_init_context()
+	 * (above) may use the wrong shadow_root_level.
+	 */
+	reset_shadow_zero_bits_mask(vcpu, context);
 }
 EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
 

arch/x86/kvm/svm/nested.c

@@ -110,7 +110,6 @@ static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
 	vcpu->arch.mmu->get_guest_pgd     = 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;
-	reset_shadow_zero_bits_mask(vcpu, vcpu->arch.mmu);
 	vcpu->arch.walk_mmu              = &vcpu->arch.nested_mmu;
 }