KVM: x86/mmu: Use shadow page role to detect PML-unfriendly pages for L2

Rework make_spte() to query the shadow page's role, specifically whether
or not it's a guest_mode page, a.k.a. a page for L2, when determining if
the SPTE is compatible with PML.  This eliminates a dependency on @vcpu,
with a future goal of being able to create SPTEs without a specific vCPU.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu_internal.h

@@ -104,7 +104,7 @@ static inline int kvm_mmu_page_as_id(struct kvm_mmu_page *sp)
 	return kvm_mmu_role_as_id(sp->role);
 }
 
-static inline bool kvm_vcpu_ad_need_write_protect(struct kvm_vcpu *vcpu)
+static inline bool kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page *sp)
 {
 	/*
 	 * When using the EPT page-modification log, the GPAs in the CPU dirty
@@ -112,10 +112,9 @@ static inline bool kvm_vcpu_ad_need_write_protect(struct kvm_vcpu *vcpu)
 	 * on write protection to record dirty pages, which bypasses PML, since
 	 * writes now result in a vmexit.  Note, the check on CPU dirty logging
 	 * being enabled is mandatory as the bits used to denote WP-only SPTEs
-	 * are reserved for NPT w/ PAE (32-bit KVM).
+	 * are reserved for PAE paging (32-bit KVM).
 	 */
-	return vcpu->arch.mmu == &vcpu->arch.guest_mmu &&
-	       kvm_x86_ops.cpu_dirty_log_size;
+	return kvm_x86_ops.cpu_dirty_log_size && sp->role.guest_mode;
 }
 
 int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,

arch/x86/kvm/mmu/spte.c

@@ -101,7 +101,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 
 	if (sp->role.ad_disabled)
 		spte |= SPTE_TDP_AD_DISABLED_MASK;
-	else if (kvm_vcpu_ad_need_write_protect(vcpu))
+	else if (kvm_mmu_page_ad_need_write_protect(sp))
 		spte |= SPTE_TDP_AD_WRPROT_ONLY_MASK;
 
 	/*