Re: [Xen-devel] [PATCH for-4.12 v2 1/8] xen/page_alloc: Move get_pg_owner()/put_pg_owner() from x86 to common code

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 20 Dec 2018, Julien Grall wrote:
> From: Benjamin Sanda <ben.sanda@xxxxxxxxxxxxxxx>
> 
> get_pg_owner() and put_pg_owner() will be necessary in a follow-up
> commit to support xentrace on Arm. So move the helper to common code.
> 
> Signed-off-by: Benjamin Sanda <ben.sanda@xxxxxxxxxxxxxxx>
> [julien: Rework commit title / turn put_pg_owner to a macro]
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

> ---
>     Changes in v2:
>         - Move get_pg_owner()/put_pg_owner() in sched.h
>         - Turn put_pg_owner() to a static inline
> ---
>  xen/arch/x86/mm.c       | 42 ------------------------------------------
>  xen/common/page_alloc.c | 38 ++++++++++++++++++++++++++++++++++++++
>  xen/include/xen/sched.h |  8 ++++++++
>  3 files changed, 46 insertions(+), 42 deletions(-)
> 
> diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
> index 1431f347f3..08f34722c2 100644
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -3089,48 +3089,6 @@ static int vcpumask_to_pcpumask(
>      }
>  }
>  
> -static struct domain *get_pg_owner(domid_t domid)
> -{
> -    struct domain *pg_owner = NULL, *curr = current->domain;
> -
> -    if ( likely(domid == DOMID_SELF) )
> -    {
> -        pg_owner = rcu_lock_current_domain();
> -        goto out;
> -    }
> -
> -    if ( unlikely(domid == curr->domain_id) )
> -    {
> -        gdprintk(XENLOG_WARNING, "Cannot specify itself as foreign 
> domain\n");
> -        goto out;
> -    }
> -
> -    switch ( domid )
> -    {
> -    case DOMID_IO:
> -        pg_owner = rcu_lock_domain(dom_io);
> -        break;
> -    case DOMID_XEN:
> -        pg_owner = rcu_lock_domain(dom_xen);
> -        break;
> -    default:
> -        if ( (pg_owner = rcu_lock_domain_by_id(domid)) == NULL )
> -        {
> -            gdprintk(XENLOG_WARNING, "Unknown domain d%d\n", domid);
> -            break;
> -        }
> -        break;
> -    }
> -
> - out:
> -    return pg_owner;
> -}
> -
> -static void put_pg_owner(struct domain *pg_owner)
> -{
> -    rcu_unlock_domain(pg_owner);
> -}
> -
>  long do_mmuext_op(
>      XEN_GUEST_HANDLE_PARAM(mmuext_op_t) uops,
>      unsigned int count,
> diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
> index 2c6509e3a0..edb93b8ada 100644
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -146,6 +146,7 @@
>  #include <asm/guest.h>
>  #include <asm/p2m.h>
>  #include <asm/setup.h> /* for highmem_start only */
> +#include <asm/paging.h>
>  #else
>  #define p2m_pod_offline_or_broken_hit(pg) 0
>  #define p2m_pod_offline_or_broken_replace(pg) BUG_ON(pg != NULL)
> @@ -2509,6 +2510,43 @@ static __init int register_heap_trigger(void)
>  }
>  __initcall(register_heap_trigger);
>  
> +struct domain *get_pg_owner(domid_t domid)
> +{
> +    struct domain *pg_owner = NULL, *curr = current->domain;
> +
> +    if ( likely(domid == DOMID_SELF) )
> +    {
> +        pg_owner = rcu_lock_current_domain();
> +        goto out;
> +    }
> +
> +    if ( unlikely(domid == curr->domain_id) )
> +    {
> +        gdprintk(XENLOG_WARNING, "Cannot specify itself as foreign 
> domain\n");
> +        goto out;
> +    }
> +
> +    switch ( domid )
> +    {
> +    case DOMID_IO:
> +        pg_owner = rcu_lock_domain(dom_io);
> +        break;
> +    case DOMID_XEN:
> +        pg_owner = rcu_lock_domain(dom_xen);
> +        break;
> +    default:
> +        if ( (pg_owner = rcu_lock_domain_by_id(domid)) == NULL )
> +        {
> +            gdprintk(XENLOG_WARNING, "Unknown domain d%d\n", domid);
> +            break;
> +        }
> +        break;
> +    }
> +
> + out:
> +    return pg_owner;
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
> diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
> index 0309c1f2a0..4956a7716c 100644
> --- a/xen/include/xen/sched.h
> +++ b/xen/include/xen/sched.h
> @@ -599,6 +599,14 @@ static inline struct domain 
> *rcu_lock_current_domain(void)
>  }
>  
>  struct domain *get_domain_by_id(domid_t dom);
> +
> +struct domain *get_pg_owner(domid_t domid);
> +
> +static inline void put_pg_owner(struct domain *pg_owner)
> +{
> +    rcu_unlock_domain(pg_owner);
> +}
> +
>  void domain_destroy(struct domain *d);
>  int domain_kill(struct domain *d);
>  int domain_shutdown(struct domain *d, u8 reason);
> -- 
> 2.11.0
> 

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