[PATCH 3/6] KVM: x86/mmu: Extract __kvm_mmu_do_page_fault()

[Paolo Bonzini]

From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

Extract out __kvm_mmu_do_page_fault() from kvm_mmu_do_page_fault().  The
inner function is to initialize struct kvm_page_fault and to call the fault
handler, and the outer function handles updating stats and converting
return code.  KVM_PRE_FAULT_MEMORY will call the KVM page fault handler.

This patch makes the emulation_type always set irrelevant to the return
code.  kvm_mmu_page_fault() is the only caller of kvm_mmu_do_page_fault(),
and references the value only when PF_RET_EMULATE is returned.  Therefore,
this adjustment doesn't affect functionality.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Message-ID: <ddf1d98420f562707b11e12c416cce8fdb986bb1.1712785629.git.isaku.yamahata@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 arch/x86/kvm/mmu/mmu_internal.h | 38 +++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index e68a60974cf4..9baae6c223ee 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -287,8 +287,8 @@ static inline void kvm_mmu_prepare_memory_fault_exit(struct kvm_vcpu *vcpu,
 				      fault->is_private);
 }
 
-static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
-					u64 err, bool prefetch, int *emulation_type)
+static inline int __kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+					  u64 err, bool prefetch, int *emulation_type)
 {
 	struct kvm_page_fault fault = {
 		.addr = cr2_or_gpa,
@@ -318,6 +318,27 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 		fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
 	}
 
+	if (IS_ENABLED(CONFIG_MITIGATION_RETPOLINE) && fault.is_tdp)
+		r = kvm_tdp_page_fault(vcpu, &fault);
+	else
+		r = vcpu->arch.mmu->page_fault(vcpu, &fault);
+
+	if (r == RET_PF_EMULATE && fault.is_private) {
+		kvm_mmu_prepare_memory_fault_exit(vcpu, &fault);
+		r = -EFAULT;
+	}
+
+	if (fault.write_fault_to_shadow_pgtable && emulation_type)
+		*emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
+
+	return r;
+}
+
+static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+					u64 err, bool prefetch, int *emulation_type)
+{
+	int r;
+
 	/*
 	 * Async #PF "faults", a.k.a. prefetch faults, are not faults from the
 	 * guest perspective and have already been counted at the time of the
@@ -326,18 +347,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 	if (!prefetch)
 		vcpu->stat.pf_taken++;
 
-	if (IS_ENABLED(CONFIG_MITIGATION_RETPOLINE) && fault.is_tdp)
-		r = kvm_tdp_page_fault(vcpu, &fault);
-	else
-		r = vcpu->arch.mmu->page_fault(vcpu, &fault);
-
-	if (r == RET_PF_EMULATE && fault.is_private) {
-		kvm_mmu_prepare_memory_fault_exit(vcpu, &fault);
-		return -EFAULT;
-	}
-
-	if (fault.write_fault_to_shadow_pgtable && emulation_type)
-		*emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
+	r = __kvm_mmu_do_page_fault(vcpu, cr2_or_gpa, err, prefetch, emulation_type);
 
 	/*
 	 * Similar to above, prefetch faults aren't truly spurious, and the
-- 
2.43.0