KVM: Move page fault processing to common code

The code that dispatches the page fault and emulates if we failed to map
is duplicated across vmx and svm.  Merge it to simplify further bugfixing.

Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 2d7d638..7fe834c 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1796,7 +1796,6 @@
 	unsigned long cr2, rip;
 	u32 vect_info;
 	enum emulation_result er;
-	int r;
 
 	vect_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
 	intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
@@ -1834,33 +1833,7 @@
 		error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
 	if (is_page_fault(intr_info)) {
 		cr2 = vmcs_readl(EXIT_QUALIFICATION);
-
-		mutex_lock(&vcpu->kvm->lock);
-		r = kvm_mmu_page_fault(vcpu, cr2, error_code);
-		if (r < 0) {
-			mutex_unlock(&vcpu->kvm->lock);
-			return r;
-		}
-		if (!r) {
-			mutex_unlock(&vcpu->kvm->lock);
-			return 1;
-		}
-
-		er = emulate_instruction(vcpu, kvm_run, cr2, error_code, 0);
-		mutex_unlock(&vcpu->kvm->lock);
-
-		switch (er) {
-		case EMULATE_DONE:
-			return 1;
-		case EMULATE_DO_MMIO:
-			++vcpu->stat.mmio_exits;
-			return 0;
-		case EMULATE_FAIL:
-			kvm_report_emulation_failure(vcpu, "pagetable");
-			break;
-		default:
-			BUG();
-		}
+		return kvm_mmu_page_fault(vcpu, cr2, error_code);
 	}
 
 	if (vcpu->rmode.active &&