Re: [Xen-devel] [PATCH v2 1/2] arm/mem_access: adjust check_and_get_page to not rely on current

[Tamas K Lengyel <tamas.lengyel@xxxxxxxxxxxx>]

On Dec 12, 2016 00:42, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:

>>> On 09.12.16 at 20:59, <tamas.lengyel@xxxxxxxxxxxx> wrote:
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -1461,7 +1461,8 @@ mfn_t gfn_to_mfn(struct domain *d, gfn_t gfn)
>   * we indeed found a conflicting mem_access setting.
>   */
>  static struct page_info*
> -p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned long flag)
> +p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned long flag,
> +                                  const struct vcpu *v)
>  {
>      long rc;
>      paddr_t ipa;
> @@ -1470,7 +1471,7 @@ 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;
> +    struct p2m_domain *p2m = &v->domain->arch.p2m;
>
>      rc = gva_to_ipa(gva, &ipa, flag);
>      if ( rc < 0 )
> @@ -1482,7 +1483,7 @@ p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned long flag)
>       * We do this first as this is faster in the default case when no
>       * permission is set on the page.
>       */
> -    rc = __p2m_get_mem_access(current->domain, gfn, &xma);
> +    rc = __p2m_get_mem_access(v->domain, gfn, &xma);
>      if ( rc < 0 )
>          goto err;
>
> @@ -1546,7 +1547,7 @@ p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned long flag)
>
>      page = mfn_to_page(mfn_x(mfn));
>
> -    if ( unlikely(!get_page(page, current->domain)) )
> +    if ( unlikely(!get_page(page, v->domain)) )
>          page = NULL;
>
>  err:

Looking at these changes, wouldn't it be more reasonable to hand
the function a struct domain *?

In its current state it might be but I believe with altp2m we will need the vcpu struct here anyway.

Tamas

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