KVM: x86/mmu: Add accessors to query mmu_role bits

Add accessors via a builder macro for all mmu_role bits that track a CR0,
CR4, or EFER bit, abstracting whether the bits are in the base or the
extended role.

Future commits will switch to using mmu_role instead of vCPU state to
configure the MMU, i.e. there are about to be a large number of users.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622175739.3610207-26-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

@@ -206,6 +206,27 @@ BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, la57, X86_CR4_LA57);
 BUILD_MMU_ROLE_REGS_ACCESSOR(efer, nx, EFER_NX);
 BUILD_MMU_ROLE_REGS_ACCESSOR(efer, lma, EFER_LMA);
 
+/*
+ * The MMU itself (with a valid role) is the single source of truth for the
+ * MMU.  Do not use the regs used to build the MMU/role, nor the vCPU.  The
+ * regs don't account for dependencies, e.g. clearing CR4 bits if CR0.PG=1,
+ * and the vCPU may be incorrect/irrelevant.
+ */
+#define BUILD_MMU_ROLE_ACCESSOR(base_or_ext, reg, name)		\
+static inline bool is_##reg##_##name(struct kvm_mmu *mmu)	\
+{								\
+	return !!(mmu->mmu_role. base_or_ext . reg##_##name);	\
+}
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr0, pg);
+BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pae);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smep);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
+BUILD_MMU_ROLE_ACCESSOR(base, efer, nx);
+
 static struct kvm_mmu_role_regs vcpu_to_role_regs(struct kvm_vcpu *vcpu)
 {
 	struct kvm_mmu_role_regs regs = {

arch/x86/kvm/mmu/paging_tmpl.h

@@ -471,7 +471,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
 
 error:
 	errcode |= write_fault | user_fault;
-	if (fetch_fault && (mmu->nx || mmu->mmu_role.ext.cr4_smep))
+	if (fetch_fault && (mmu->nx || is_cr4_smep(mmu)))
 		errcode |= PFERR_FETCH_MASK;
 
 	walker->fault.vector = PF_VECTOR;