Re: [Xen-devel] [PATCH 26/38] arm: fix locking in create_p2m_entries

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 1 Jun 2012, Ian Campbell wrote:
> For some reason we were holding the lock over only the unmaps at the end of
> the function, rather than for the whole walk.
> 
> We might want to be more clever in the future, but for now lets just lock for
> the whole walk+create process.
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>


Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

>  xen/arch/arm/p2m.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 46c6f17..c4daf83 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -168,6 +168,8 @@ static int create_p2m_entries(struct domain *d,
>      paddr_t addr;
>      unsigned long cur_first_offset = ~0, cur_second_offset = ~0;
>  
> +    spin_lock(&p2m->lock);
> +
>      /* XXX Don't actually handle 40 bit guest physical addresses */
>      BUG_ON(start_gpaddr & 0x8000000000ULL);
>      BUG_ON(end_gpaddr   & 0x8000000000ULL);
> @@ -249,8 +251,6 @@ static int create_p2m_entries(struct domain *d,
>      rc = 0;
>  
>  out:
> -    spin_lock(&p2m->lock);
> -
>      if (third) unmap_domain_page(third);
>      if (second) unmap_domain_page(second);
>      if (first) unmap_domain_page(first);
> -- 
> 1.7.9.1
> 
> 
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> 

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