Re: [Xen-devel] [PATCH v4 7/7] Revert "xen: introduce arch_grant_(un)map_page_identity"

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Stefano,

On 10/10/2014 12:44, Stefano Stabellini wrote:
> This reverts commit e25a5f4d8cf3b55718048abdd21c7d0de64ae54c.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxxxxx>

Regards,

> ---
>   xen/arch/arm/p2m.c                 |   26 --------------------------
>   xen/drivers/passthrough/arm/smmu.c |   13 +++++++++++--
>   xen/include/asm-arm/p2m.h          |    4 ----
>   xen/include/asm-x86/p2m.h          |    4 ----
>   4 files changed, 11 insertions(+), 36 deletions(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 6ff8c17..acad2f2 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -931,32 +931,6 @@ void guest_physmap_remove_page(struct domain *d,
>                         pfn_to_paddr(mfn), MATTR_MEM, p2m_invalid);
>   }
>
> -int arch_grant_map_page_identity(struct domain *d, unsigned long frame,
> -                                 bool_t writeable)
> -{
> -    p2m_type_t t;
> -
> -    ASSERT(is_domain_direct_mapped(d));
> -
> -    /* This is not an IOMMU mapping but it is not a regular RAM p2m type
> -     * either. We are using IOMMU p2m types here to prevent the pages
> -     * from being used as grants. */
> -    if ( writeable )
> -        t = p2m_iommu_map_rw;
> -    else
> -        t = p2m_iommu_map_ro;
> -
> -    return guest_physmap_add_entry(d, frame, frame, 0, t);
> -}
> -
> -int arch_grant_unmap_page_identity(struct domain *d, unsigned long frame)
> -{
> -    ASSERT(is_domain_direct_mapped(d));
> -
> -    guest_physmap_remove_page(d, frame, frame, 0);
> -    return 0;
> -}
> -
>   int p2m_alloc_table(struct domain *d)
>   {
>       struct p2m_domain *p2m = &d->arch.p2m;
> diff --git a/xen/drivers/passthrough/arm/smmu.c 
> b/xen/drivers/passthrough/arm/smmu.c
> index 9a95ac9..42bde75 100644
> --- a/xen/drivers/passthrough/arm/smmu.c
> +++ b/xen/drivers/passthrough/arm/smmu.c
> @@ -1539,6 +1539,8 @@ static void arm_smmu_iommu_domain_teardown(struct domain 
> *d)
>   static int arm_smmu_map_page(struct domain *d, unsigned long gfn,
>                                unsigned long mfn, unsigned int flags)
>   {
> +    p2m_type_t t;
> +
>       /* Grant mappings can be used for DMA requests. The dev_bus_addr returned 
> by
>        * the hypercall is the MFN (not the IPA). For device protected by
>        * an IOMMU, Xen needs to add a 1:1 mapping in the domain p2m to
> @@ -1553,7 +1555,12 @@ static int arm_smmu_map_page(struct domain *d, unsigned 
> long gfn,
>       if ( !(flags & (IOMMUF_readable | IOMMUF_writable)) )
>           return -EINVAL;
>
> -    return arch_grant_map_page_identity(d, mfn, flags & IOMMUF_writable);
> +    t = (flags & IOMMUF_writable) ? p2m_iommu_map_rw : p2m_iommu_map_ro;
> +
> +    /* The function guest_physmap_add_entry replaces the current mapping
> +     * if there is already one...
> +     */
> +    return guest_physmap_add_entry(d, gfn, mfn, 0, t);
>   }
>
>   static int arm_smmu_unmap_page(struct domain *d, unsigned long gfn)
> @@ -1564,7 +1571,9 @@ static int arm_smmu_unmap_page(struct domain *d, unsigned 
> long gfn)
>       if ( !is_domain_direct_mapped(d) )
>           return -EINVAL;
>
> -    return arch_grant_unmap_page_identity(d, gfn);
> +    guest_physmap_remove_page(d, gfn, gfn, 0);
> +
> +    return 0;
>   }
>
>   static const struct iommu_ops arm_smmu_iommu_ops = {
> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
> index 10bf111..da36504 100644
> --- a/xen/include/asm-arm/p2m.h
> +++ b/xen/include/asm-arm/p2m.h
> @@ -214,10 +214,6 @@ static inline int get_page_and_type(struct page_info *page,
>       return rc;
>   }
>
> -int arch_grant_map_page_identity(struct domain *d, unsigned long frame,
> -                                 bool_t writeable);
> -int arch_grant_unmap_page_identity(struct domain *d, unsigned long frame);
> -
>   /* get host p2m table */
>   #define p2m_get_hostp2m(d) (&(d)->arch.p2m)
>
> diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
> index 90ddd15..5f7fe71 100644
> --- a/xen/include/asm-x86/p2m.h
> +++ b/xen/include/asm-x86/p2m.h
> @@ -709,10 +709,6 @@ static inline unsigned int p2m_get_iommu_flags(p2m_type_t 
> p2mt)
>       return flags;
>   }
>
> -extern int arch_grant_map_page_identity(struct domain *d, unsigned long frame,
> -                                 bool_t writeable);
> -extern int arch_grant_unmap_page_identity(struct domain *d, unsigned long 
> frame);
> -
>   #endif /* _XEN_P2M_H */
>
>   /*
--
Julien Grall

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