Re: [Xen-devel] [RFC 13/22] xen/arm: p2m: Replace all usage of __p2m_lookup with p2m_get_entry

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

On Thu, Jul 28, 2016 at 8:51 AM, Julien Grall <julien.grall@xxxxxxx> wrote:
> __p2m_lookup is just a wrapper to p2m_get_entry.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Cc: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
> Cc: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
>
> ---
>     It might be possible to rework the memaccess code to take advantage
>     of all the parameters. I will defer this to the memaccess folks.

Could you elaborate on what you mean?

> ---
>  xen/arch/arm/p2m.c | 18 ++++--------------
>  1 file changed, 4 insertions(+), 14 deletions(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 8676b9d..9a9c85c 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -398,24 +398,13 @@ out:
>      return mfn;
>  }
>
> -/*
> - * Lookup the MFN corresponding to a domain's GFN.
> - *
> - * There are no processor functions to do a stage 2 only lookup therefore we
> - * do a a software walk.
> - */
> -static mfn_t __p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
> -{
> -    return p2m_get_entry(&d->arch.p2m, gfn, t, NULL, NULL);
> -}
> -
>  mfn_t p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
>  {
>      mfn_t ret;
>      struct p2m_domain *p2m = &d->arch.p2m;
>
>      p2m_read_lock(p2m);
> -    ret = __p2m_lookup(d, gfn, t);
> +    ret = p2m_get_entry(p2m, gfn, t, NULL, NULL);
>      p2m_read_unlock(p2m);
>
>      return ret;
> @@ -679,7 +668,7 @@ static int __p2m_get_mem_access(struct domain *d, gfn_t 
> gfn,
>           * No setting was found in the Radix tree. Check if the
>           * entry exists in the page-tables.
>           */
> -        mfn_t mfn = __p2m_lookup(d, gfn, NULL);
> +        mfn_t mfn = p2m_get_entry(p2m, gfn, NULL, NULL, NULL);
>
>          if ( mfn_eq(mfn, INVALID_MFN) )
>              return -ESRCH;
> @@ -1595,6 +1584,7 @@ p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned 
> long flag)
>      xenmem_access_t xma;
>      p2m_type_t t;
>      struct page_info *page = NULL;
> +    struct p2m_domain *p2m = &current->domain->arch.p2m;

I think this would be a good time to change this and pass p2m as an
input to p2m_mem_access_check_and_get_page. This would help with our
altp2m series as well.

Thanks,
Tamas

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