Re: [Xen-devel] [PATCH for 4.5] xen/arm: Initialize the domain vgic lock

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2014-12-17 at 15:40 +0000, Julien Grall wrote:
> The domain vgic lock is used uninitialized.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

> ---
>     This is a bug fix for Xen 4.5 and Xen 4.4. The vgic lock is used
>     unitialized. Luckily we only use the field "raw" which is reset to 0
>     during the domain allocation.
> 
>     There is no harm to apply for Xen 4.5 because it will correctly set
>     the spin_lock structure for a later usage.

By your above reasoning there is also no point, is there? That said, I
think we should take this since as you say it is harmless and good
practice to initialise spinlocks even if not strictly necessary.

> ---
>  xen/arch/arm/vgic.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
> index 97061ce..b8bd38b 100644
> --- a/xen/arch/arm/vgic.c
> +++ b/xen/arch/arm/vgic.c
> @@ -90,6 +90,8 @@ int domain_vgic_init(struct domain *d)
>          return -ENODEV;
>      }
>  
> +    spin_lock_init(&d->arch.vgic.lock);
> +
>      d->arch.vgic.shared_irqs =
>          xzalloc_array(struct vgic_irq_rank, DOMAIN_NR_RANKS(d));
>      if ( d->arch.vgic.shared_irqs == NULL )




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