[RFC PATCH 4/8] KVM: x86/mmu: Factor out kvm_mmu_do_page_fault()

[isaku . yamahata]

From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

For ioctl to pre-populate guest memory, factor out kvm_mmu_do_page_fault()
into initialization function of struct kvm_page_fault, calling fault hander,
and the surrounding logic of error check and stats update part.  This
enables to implement a wrapper to call fault handler.

No functional change intended.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
 arch/x86/kvm/mmu/mmu_internal.h | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 72ef09fc9322..aac52f0fdf54 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -302,6 +302,24 @@ enum {
 	.pfn = KVM_PFN_ERR_FAULT,						\
 	.hva = KVM_HVA_ERR_BAD, }
 
+static inline int __kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu,
+					  struct kvm_page_fault *fault)
+{
+	int r;
+
+	if (vcpu->arch.mmu->root_role.direct) {
+		fault->gfn = fault->addr >> PAGE_SHIFT;
+		fault->slot = kvm_vcpu_gfn_to_memslot(vcpu, fault->gfn);
+	}
+
+	if (IS_ENABLED(CONFIG_RETPOLINE) && fault->is_tdp)
+		r = kvm_tdp_page_fault(vcpu, fault);
+	else
+		r = vcpu->arch.mmu->page_fault(vcpu, fault);
+
+	return r;
+}
+
 static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 					u32 err, bool prefetch, int *emulation_type)
 {
@@ -310,11 +328,6 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 							  KVM_MAX_HUGEPAGE_LEVEL);
 	int r;
 
-	if (vcpu->arch.mmu->root_role.direct) {
-		fault.gfn = fault.addr >> PAGE_SHIFT;
-		fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
-	}
-
 	/*
 	 * 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
@@ -323,10 +336,7 @@ 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_RETPOLINE) && fault.is_tdp)
-		r = kvm_tdp_page_fault(vcpu, &fault);
-	else
-		r = vcpu->arch.mmu->page_fault(vcpu, &fault);
+	r = __kvm_mmu_do_page_fault(vcpu, &fault);
 
 	if (fault.write_fault_to_shadow_pgtable && emulation_type)
 		*emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
-- 
2.25.1