KVM: VMX: Rename vcpu_vmx's "save_nmsrs" to "nr_active_uret_msrs"

Add "uret" into the name of "save_nmsrs" to explicitly associate it with
the guest_uret_msrs array, and replace "save" with "active" (for lack of
a better word) to better describe what is being tracked.  While "save"
is more or less accurate when viewed as a literal description of the
field, e.g. it holds the number of MSRs that were saved into the array
the last time setup_msrs() was invoked, it can easily be misinterpreted
by the reader, e.g. as meaning the number of MSRs that were saved from
hardware at some point in the past, or as the number of MSRs that need
to be saved at some point in the future, both of which are wrong.

No functional change intended.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200923180409.32255-7-sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -637,7 +637,7 @@ static int vmx_set_guest_msr(struct vcpu_vmx *vmx, struct vmx_uret_msr *msr, u64
 
 	u64 old_msr_data = msr->data;
 	msr->data = data;
-	if (msr - vmx->guest_uret_msrs < vmx->save_nmsrs) {
+	if (msr - vmx->guest_uret_msrs < vmx->nr_active_uret_msrs) {
 		preempt_disable();
 		ret = kvm_set_user_return_msr(msr->index, msr->data, msr->mask);
 		preempt_enable();
@@ -1136,7 +1136,7 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
 	 */
 	if (!vmx->guest_msrs_ready) {
 		vmx->guest_msrs_ready = true;
-		for (i = 0; i < vmx->save_nmsrs; ++i)
+		for (i = 0; i < vmx->nr_active_uret_msrs; ++i)
 			kvm_set_user_return_msr(vmx->guest_uret_msrs[i].index,
 						vmx->guest_uret_msrs[i].data,
 						vmx->guest_uret_msrs[i].mask);
@@ -1628,9 +1628,9 @@ static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
  */
 static void setup_msrs(struct vcpu_vmx *vmx)
 {
-	int save_nmsrs, index;
+	int nr_active_uret_msrs, index;
 
-	save_nmsrs = 0;
+	nr_active_uret_msrs = 0;
 #ifdef CONFIG_X86_64
 	/*
 	 * The SYSCALL MSRs are only needed on long mode guests, and only
@@ -1639,26 +1639,26 @@ static void setup_msrs(struct vcpu_vmx *vmx)
 	if (is_long_mode(&vmx->vcpu) && (vmx->vcpu.arch.efer & EFER_SCE)) {
 		index = __find_msr_index(vmx, MSR_STAR);
 		if (index >= 0)
-			move_msr_up(vmx, index, save_nmsrs++);
+			move_msr_up(vmx, index, nr_active_uret_msrs++);
 		index = __find_msr_index(vmx, MSR_LSTAR);
 		if (index >= 0)
-			move_msr_up(vmx, index, save_nmsrs++);
+			move_msr_up(vmx, index, nr_active_uret_msrs++);
 		index = __find_msr_index(vmx, MSR_SYSCALL_MASK);
 		if (index >= 0)
-			move_msr_up(vmx, index, save_nmsrs++);
+			move_msr_up(vmx, index, nr_active_uret_msrs++);
 	}
 #endif
 	index = __find_msr_index(vmx, MSR_EFER);
 	if (index >= 0 && update_transition_efer(vmx, index))
-		move_msr_up(vmx, index, save_nmsrs++);
+		move_msr_up(vmx, index, nr_active_uret_msrs++);
 	index = __find_msr_index(vmx, MSR_TSC_AUX);
 	if (index >= 0 && guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
-		move_msr_up(vmx, index, save_nmsrs++);
+		move_msr_up(vmx, index, nr_active_uret_msrs++);
 	index = __find_msr_index(vmx, MSR_IA32_TSX_CTRL);
 	if (index >= 0)
-		move_msr_up(vmx, index, save_nmsrs++);
+		move_msr_up(vmx, index, nr_active_uret_msrs++);
 
-	vmx->save_nmsrs = save_nmsrs;
+	vmx->nr_active_uret_msrs = nr_active_uret_msrs;
 	vmx->guest_msrs_ready = false;
 
 	if (cpu_has_vmx_msr_bitmap())

arch/x86/kvm/vmx/vmx.h

@@ -198,7 +198,7 @@ struct vcpu_vmx {
 
 	struct vmx_uret_msr   guest_uret_msrs[MAX_NR_USER_RETURN_MSRS];
 	int                   nr_uret_msrs;
-	int                   save_nmsrs;
+	int                   nr_active_uret_msrs;
 	bool                  guest_msrs_ready;
 #ifdef CONFIG_X86_64
 	u64		      msr_host_kernel_gs_base;