Re: [PATCH v3 3/3] xen: mem_access: conditionally compile vm_event.c & monitor.c

[Jan Beulich <jbeulich@xxxxxxxx>]

On 11.03.2025 11:27, Sergiy Kibrik wrote:
> From: Stefano Stabellini <stefano.stabellini@xxxxxxx>
> 
> Extend coverage of CONFIG_VM_EVENT option and make the build of VM events
> and monitoring support optional. Also make MEM_PAGING option depend on 
> VM_EVENT
> to document that mem_paging is relying on vm_event.
> This is to reduce code size on Arm when this option isn't enabled.
> 
> CC: Jan Beulich <jbeulich@xxxxxxxx>
> CC: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
> Reviewed-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
> Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>

Please can tags be kept in chronological order? It's impossible to review
a patch that wasn't first signed-off on by the author(s).

> ---
> changes in v3:
>  - add dependency MEM_PAGING -> VM_EVENT
>  - monitor_domctl() stub returns -EOPNOTSUPP

Seeing this, i.e. ...

> --- a/xen/include/xen/monitor.h
> +++ b/xen/include/xen/monitor.h
> @@ -27,8 +27,17 @@
>  struct domain;
>  struct xen_domctl_monitor_op;
>  
> +#ifdef CONFIG_VM_EVENT
>  int monitor_domctl(struct domain *d, struct xen_domctl_monitor_op *mop);
>  void monitor_guest_request(void);
> +#else
> +static inline int monitor_domctl(struct domain *d,
> +                                 struct xen_domctl_monitor_op *mop)
> +{
> +    return -EOPNOTSUPP;

... this, why ...

> @@ -88,7 +85,18 @@ void vm_event_cancel_slot(struct domain *d, struct 
> vm_event_domain *ved);
>  void vm_event_put_request(struct domain *d, struct vm_event_domain *ved,
>                            vm_event_request_t *req);
>  
> +#ifdef CONFIG_VM_EVENT
> +/* Clean up on domain destruction */
> +void vm_event_cleanup(struct domain *d);
>  int vm_event_domctl(struct domain *d, struct xen_domctl_vm_event_op *vec);
> +#else
> +static inline void vm_event_cleanup(struct domain *d) {}
> +static inline int vm_event_domctl(struct domain *d,
> +                                  struct xen_domctl_vm_event_op *vec)
> +{
> +    return -EINVAL;

... is it EINVAL here?

Jan