KVM: VMX: Dedup code for removing MSR from VMCS's auto-load list

Add a helper to remove an MSR from an auto-{load,store} list to dedup the
msr_autoload code, and in anticipation of adding similar functionality for
msr_autostore.

No functional change intended.

Tested-by: Manali Shukla <manali.shukla@amd.com>
Link: https://patch.msgid.link/20251206001720.468579-38-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/vmx/vmx.c

@@ -1040,9 +1040,22 @@ static int vmx_find_loadstore_msr_slot(struct vmx_msrs *m, u32 msr)
 	return -ENOENT;
 }
 
-static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
+static void vmx_remove_auto_msr(struct vmx_msrs *m, u32 msr,
+				unsigned long vmcs_count_field)
 {
 	int i;
+
+	i = vmx_find_loadstore_msr_slot(m, msr);
+	if (i < 0)
+		return;
+
+	--m->nr;
+	m->val[i] = m->val[m->nr];
+	vmcs_write32(vmcs_count_field, m->nr);
+}
+
+static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
+{
 	struct msr_autoload *m = &vmx->msr_autoload;
 
 	switch (msr) {
@@ -1063,21 +1076,9 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
 		}
 		break;
 	}
-	i = vmx_find_loadstore_msr_slot(&m->guest, msr);
-	if (i < 0)
-		goto skip_guest;
-	--m->guest.nr;
-	m->guest.val[i] = m->guest.val[m->guest.nr];
-	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
-
-skip_guest:
-	i = vmx_find_loadstore_msr_slot(&m->host, msr);
-	if (i < 0)
-		return;
 
-	--m->host.nr;
-	m->host.val[i] = m->host.val[m->host.nr];
-	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
+	vmx_remove_auto_msr(&m->guest, msr, VM_ENTRY_MSR_LOAD_COUNT);
+	vmx_remove_auto_msr(&m->host, msr, VM_EXIT_MSR_LOAD_COUNT);
 }
 
 static __always_inline void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,