KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level

The guest memory population logic will need to know what page size or level
(4K, 2M, ...) is mapped.
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Message-ID: <eabc3f3e5eb03b370cadf6e1901ea34d7a020adc.1712785629.git.isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

@@ -4292,7 +4292,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
 		return;
 
 	r = kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, work->arch.error_code,
-				  true, NULL);
+				  true, NULL, NULL);
 
 	/*
 	 * Account fixed page faults, otherwise they'll never be counted, but
@@ -5937,7 +5937,7 @@ int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 err
 		vcpu->stat.pf_taken++;
 
 		r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa, error_code, false,
-					  &emulation_type);
+					  &emulation_type, NULL);
 		if (KVM_BUG_ON(r == RET_PF_INVALID, vcpu->kvm))
 			return -EIO;
 	}

arch/x86/kvm/mmu/mmu_internal.h

@@ -288,7 +288,8 @@ static inline void kvm_mmu_prepare_memory_fault_exit(struct kvm_vcpu *vcpu,
 }
 
 static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
-					u64 err, bool prefetch, int *emulation_type)
+					u64 err, bool prefetch,
+					int *emulation_type, u8 *level)
 {
 	struct kvm_page_fault fault = {
 		.addr = cr2_or_gpa,
@@ -336,6 +337,8 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 
 	if (fault.write_fault_to_shadow_pgtable && emulation_type)
 		*emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
+	if (level)
+		*level = fault.goal_level;
 
 	return r;
 }