Re: [PATCH v2 13/25] arm/altp2m: Make p2m_restore_state ready for altp2m.

[Julien Grall <julien.grall@arm.com>]

Hello,

On 01/08/16 18:10, Sergej Proskurin wrote:
> This commit adapts the function "p2m_restore_state" in a way that the
> currently active altp2m table is considered during state restoration.
>
> Signed-off-by: Sergej Proskurin <proskurin@sec.in.tum.de>
> ---
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: Julien Grall <julien.grall@arm.com>
> ---
>  xen/arch/arm/p2m.c           | 4 +++-
>  xen/include/asm-arm/altp2m.h | 3 +++
>  2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 8afea11..bcad51f 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -115,7 +115,9 @@ void p2m_save_state(struct vcpu *p)
>  void p2m_restore_state(struct vcpu *n)
>  {
>      register_t hcr;
> -    struct p2m_domain *p2m = &n->domain->arch.p2m;
> +    struct domain *d = n->domain;
> +    struct p2m_domain *p2m = unlikely(altp2m_active(d)) ?
> +                             altp2m_get_altp2m(n) : p2m_get_hostp2m(d);

This seems to be a common idiom in multiple place. I would like to see a 
helper for this.

However, I think this could be avoided if you store a pointer to the p2m 
directly in arch_vcpu.

>
>      if ( is_idle_vcpu(n) )
>          return;
> diff --git a/xen/include/asm-arm/altp2m.h b/xen/include/asm-arm/altp2m.h
> index 790bb33..a6496b7 100644
> --- a/xen/include/asm-arm/altp2m.h
> +++ b/xen/include/asm-arm/altp2m.h
> @@ -49,6 +49,9 @@ void altp2m_teardown(struct domain *d);
>  void altp2m_vcpu_initialise(struct vcpu *v);
>  void altp2m_vcpu_destroy(struct vcpu *v);
>
> +/* Get current alternate p2m table. */
> +struct p2m_domain *altp2m_get_altp2m(struct vcpu *v);
> +

This should be added in the patch where the function was added (i.e 
patch #8).

>  /* Switch alternate p2m for entire domain */
>  int altp2m_switch_domain_altp2m_by_id(struct domain *d,
>                                        unsigned int idx);
>

Regards,

-- 
Julien Grall

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