linux-kernel - [PATCH 25/54] KVM: x86/mmu: Add helpers to query mmu

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Date:   Tue, 22 Jun 2021 10:57:10 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Yu Zhang <yu.c.zhang@...ux.intel.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 25/54] KVM: x86/mmu: Add helpers to query mmu_role bits

Add helpers via a builder macro for all mmu_role bits that track a CR0,
CR4, or EFER bit.  Digging out the bits manually is not exactly the most
readable code.

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@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c         | 21 +++++++++++++++++++++
 arch/x86/kvm/mmu/paging_tmpl.h |  2 +-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 7bc5b1a8fca5..be95595b30c7 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/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);
+
 struct kvm_mmu_role_regs vcpu_to_role_regs(struct kvm_vcpu *vcpu)
 {
 	struct kvm_mmu_role_regs regs = {
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index b632606a87d6..5cf36eb96ee2 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/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;
-- 
2.32.0.288.g62a8d224e6-goog