Re: [Xen-devel] [PATCH v1 02/14] x86/np2m: add np2m_flush_base()

[George Dunlap <george.dunlap@xxxxxxxxxx>]

On 09/04/2017 09:14 AM, Sergey Dyasli wrote:
> The new function finds all np2m objects with the specified np2m_base
> and flushes them.
> 
> Convert p2m_flush_table() into p2m_flush_table_locked() in order not to
> release the p2m_lock after np2m_base check.
> 
> Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>

Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>

> ---
> RFC --> v1:
> - p2m_unlock(p2m) is moved from p2m_flush_table_locked() to
>   p2m_flush_table() for balanced lock/unlock
> - np2m_flush_eptp() is renamed to np2m_flush_base()
> 
>  xen/arch/x86/mm/p2m.c     | 35 +++++++++++++++++++++++++++++------
>  xen/include/asm-x86/p2m.h |  2 ++
>  2 files changed, 31 insertions(+), 6 deletions(-)
> 
> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
> index b8c8bba421..94a42400ad 100644
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -1708,15 +1708,14 @@ p2m_getlru_nestedp2m(struct domain *d, struct 
> p2m_domain *p2m)
>      return p2m;
>  }
>  
> -/* Reset this p2m table to be empty */
>  static void
> -p2m_flush_table(struct p2m_domain *p2m)
> +p2m_flush_table_locked(struct p2m_domain *p2m)
>  {
>      struct page_info *top, *pg;
>      struct domain *d = p2m->domain;
>      mfn_t mfn;
>  
> -    p2m_lock(p2m);
> +    ASSERT(p2m_locked_by_me(p2m));
>  
>      /*
>       * "Host" p2m tables can have shared entries &c that need a bit more care
> @@ -1729,10 +1728,7 @@ p2m_flush_table(struct p2m_domain *p2m)
>  
>      /* No need to flush if it's already empty */
>      if ( p2m_is_nestedp2m(p2m) && p2m->np2m_base == P2M_BASE_EADDR )
> -    {
> -        p2m_unlock(p2m);
>          return;
> -    }
>  
>      /* This is no longer a valid nested p2m for any address space */
>      p2m->np2m_base = P2M_BASE_EADDR;
> @@ -1752,7 +1748,14 @@ p2m_flush_table(struct p2m_domain *p2m)
>              d->arch.paging.free_page(d, pg);
>      }
>      page_list_add(top, &p2m->pages);
> +}
>  
> +/* Reset this p2m table to be empty */
> +static void
> +p2m_flush_table(struct p2m_domain *p2m)
> +{
> +    p2m_lock(p2m);
> +    p2m_flush_table_locked(p2m);
>      p2m_unlock(p2m);
>  }
>  
> @@ -1773,6 +1776,26 @@ p2m_flush_nestedp2m(struct domain *d)
>          p2m_flush_table(d->arch.nested_p2m[i]);
>  }
>  
> +void np2m_flush_base(struct vcpu *v, unsigned long np2m_base)
> +{
> +    struct domain *d = v->domain;
> +    struct p2m_domain *p2m;
> +    unsigned int i;
> +
> +    np2m_base &= ~(0xfffull);
> +
> +    nestedp2m_lock(d);
> +    for ( i = 0; i < MAX_NESTEDP2M; i++ )
> +    {
> +        p2m = d->arch.nested_p2m[i];
> +        p2m_lock(p2m);
> +        if ( p2m->np2m_base == np2m_base )
> +            p2m_flush_table_locked(p2m);
> +        p2m_unlock(p2m);
> +    }
> +    nestedp2m_unlock(d);
> +}
> +
>  static void assign_np2m(struct vcpu *v, struct p2m_domain *p2m)
>  {
>      struct nestedvcpu *nv = &vcpu_nestedhvm(v);
> diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
> index 9086bb35dc..cfb00591cd 100644
> --- a/xen/include/asm-x86/p2m.h
> +++ b/xen/include/asm-x86/p2m.h
> @@ -779,6 +779,8 @@ int p2m_pt_handle_deferred_changes(uint64_t gpa);
>  void p2m_flush(struct vcpu *v, struct p2m_domain *p2m);
>  /* Flushes all nested p2m tables */
>  void p2m_flush_nestedp2m(struct domain *d);
> +/* Flushes all np2m objects with the specified np2m_base */
> +void np2m_flush_base(struct vcpu *v, unsigned long np2m_base);
>  
>  void nestedp2m_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
>      l1_pgentry_t *p, l1_pgentry_t new, unsigned int level);
> 


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