linux-kernel - [PATCH v2 02/22] KVM: x86/mmu: Replace PFERR_NESTED_GUEST

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Message-ID: <20240831001538.336683-3-seanjc@google.com>
Date: Fri, 30 Aug 2024 17:15:17 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Yuan Yao <yuan.yao@...el.com>, Yuan Yao <yuan.yao@...ux.intel.com>
Subject: [PATCH v2 02/22] KVM: x86/mmu: Replace PFERR_NESTED_GUEST_PAGE with a
 more descriptive helper

Drop the globally visible PFERR_NESTED_GUEST_PAGE and replace it with a
more appropriately named is_write_to_guest_page_table().  The macro name
is misleading, because while all nNPT walks match PAGE|WRITE|PRESENT, the
reverse is not true.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/include/asm/kvm_host.h | 4 ----
 arch/x86/kvm/mmu/mmu.c          | 9 ++++++++-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1811a42fa093..62d19403d63c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -280,10 +280,6 @@ enum x86_intercept_stage;
 #define PFERR_PRIVATE_ACCESS   BIT_ULL(49)
 #define PFERR_SYNTHETIC_MASK   (PFERR_IMPLICIT_ACCESS | PFERR_PRIVATE_ACCESS)
 
-#define PFERR_NESTED_GUEST_PAGE (PFERR_GUEST_PAGE_MASK |	\
-				 PFERR_WRITE_MASK |		\
-				 PFERR_PRESENT_MASK)
-
 /* apic attention bits */
 #define KVM_APIC_CHECK_VAPIC	0
 /*
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index d25c2b395116..4ca01256143e 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5947,6 +5947,13 @@ void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
 	write_unlock(&vcpu->kvm->mmu_lock);
 }
 
+static bool is_write_to_guest_page_table(u64 error_code)
+{
+	const u64 mask = PFERR_GUEST_PAGE_MASK | PFERR_WRITE_MASK | PFERR_PRESENT_MASK;
+
+	return (error_code & mask) == mask;
+}
+
 int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,
 		       void *insn, int insn_len)
 {
@@ -6010,7 +6017,7 @@ int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 err
 	 * and resume the guest.
 	 */
 	if (vcpu->arch.mmu->root_role.direct &&
-	    (error_code & PFERR_NESTED_GUEST_PAGE) == PFERR_NESTED_GUEST_PAGE) {
+	    is_write_to_guest_page_table(error_code)) {
 		kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(cr2_or_gpa));
 		return 1;
 	}
-- 
2.46.0.469.g59c65b2a67-goog