KVM: nVMX: Mark APIC access page dirty when syncing vmcs12 pages

For consistency with commit 7afe79f ("KVM: nVMX: Mark vmcs12's APIC
access page dirty when unmapping"), which marks the page dirty during
unmap operations, also mark it dirty during vmcs12 page synchronization.

Signed-off-by: Fred Griffoul <fgriffo@amazon.co.uk>
[sean: use kvm_vcpu_map_mark_dirty()]
Link: https://patch.msgid.link/20251121223444.355422-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: Fred Griffoul

arch/x86/kvm/vmx/vmx.c

@@ -6382,10 +6382,7 @@ static void nested_vmx_mark_all_vmcs12_pages_dirty(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
-	/*
-	 * Don't need to mark the APIC access page dirty; it is never
-	 * written to by the CPU during APIC virtualization.
-	 */
+	kvm_vcpu_map_mark_dirty(vcpu, &vmx->nested.apic_access_page_map);
 	kvm_vcpu_map_mark_dirty(vcpu, &vmx->nested.virtual_apic_map);
 	kvm_vcpu_map_mark_dirty(vcpu, &vmx->nested.pi_desc_map);
 }