[PATCH 5/6] nVMX x86: Re-organize the code in check_vmentry_prereqs(), that are related to VM-Exit Control Fields

[Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>]

Separate out the checks in check_vmentry_prereqs(), that are related to the
VM-Exit Control Fields, to a separate function. The re-organized code is
easier for readability, enhancement and maintenance.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
Reviewed-by: Mihai Carabas <mihai.carabas@xxxxxxxxxx>
Reviewed-by: Mark Kanda <mark.kanda@xxxxxxxxxx>
---
 arch/x86/kvm/vmx.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 68335f5..b063cfa 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11692,18 +11692,26 @@ static int nested_vmx_check_msr_switch(struct kvm_vcpu *vcpu,
 static int nested_vmx_check_msr_switch_controls(struct kvm_vcpu *vcpu,
 						struct vmcs12 *vmcs12)
 {
+	if (vmcs12->vm_entry_msr_load_count == 0)
+		return 0; /* Fast path */
+	if (nested_vmx_check_msr_switch(vcpu, VM_ENTRY_MSR_LOAD_COUNT,
+					VM_ENTRY_MSR_LOAD_ADDR))
+		return -EINVAL;
+	return 0;
+}
+
+static int nested_vmx_check_exit_msr_switch_controls(struct kvm_vcpu *vcpu,
+						struct vmcs12 *vmcs12)
+{
 	if (vmcs12->vm_exit_msr_load_count == 0 &&
-	    vmcs12->vm_exit_msr_store_count == 0 &&
-	    vmcs12->vm_entry_msr_load_count == 0)
+	    vmcs12->vm_exit_msr_store_count == 0)
 		return 0; /* Fast path */
 	if (nested_vmx_check_msr_switch(vcpu, VM_EXIT_MSR_LOAD_COUNT,
 					VM_EXIT_MSR_LOAD_ADDR) ||
 	    nested_vmx_check_msr_switch(vcpu, VM_EXIT_MSR_STORE_COUNT,
-					VM_EXIT_MSR_STORE_ADDR) ||
-	    nested_vmx_check_msr_switch(vcpu, VM_ENTRY_MSR_LOAD_COUNT,
-					VM_ENTRY_MSR_LOAD_ADDR))
+					VM_EXIT_MSR_STORE_ADDR))
 		return -EINVAL;
-	return 0;
+        return 0;
 }
 
 static int nested_vmx_check_pml_controls(struct kvm_vcpu *vcpu,
@@ -12387,13 +12395,25 @@ static int nested_check_vm_execution_ctls(struct vmcs12 *vmcs12)
 	return 0;
 }
 
+/*
+ * Checks related to VM-Exit Control Fields
+ */
+static int nested_check_vm_exit_ctls(struct vmcs12 *vmcs12)
+{
+	if (nested_vmx_check_exit_msr_switch_controls(vcpu, vmcs12))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int nested_check_vmentry_prereqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
 	if (nested_check_guest_state_area(vmcs12) ||
 	    nested_check_host_state_area(vmcs12) ||
-	    nested_check_vm_execution_ctls(vmcs12))
+	    nested_check_vm_execution_ctls(vmcs12) ||
+	    nested_check_vm_exit_ctls(vmcs12))
 		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
 
 	if (nested_vmx_check_msr_switch_controls(vcpu, vmcs12))
-- 
2.9.5