Re: [Xen-devel] [PATCH 20/24] xen/arm: mm: Redefine virt_to_mfn to support typesafe

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 13 Jun 2017, Julien Grall wrote:
> The file xen/arch/arm/mm.c is using the typesafe MFN in most of the
> place. This requires all caller of virt_to_mfn to prefixed by _mfn(...).
> 
> To avoid the extra _mfn(...), re-defined virt_to_mfn within arch/arm/mm.c
> to handle typesafe MFN.
> 
> This patch also introduce __virt_to_mfn, so virt_to_mfn can be
> re-defined easily.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> ---
>  xen/arch/arm/mm.c        | 16 ++++++++++------
>  xen/include/asm-arm/mm.h |  3 ++-
>  2 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 452c1e26c3..2ff1688f3f 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -44,6 +44,10 @@
>  
>  struct domain *dom_xen, *dom_io, *dom_cow;
>  
> +/* Override macros from asm/page.h to make them work with mfn_t */
> +#undef virt_to_mfn
> +#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
> +
>  /* Static start-of-day pagetables that we use before the allocators
>   * are up. These are used by all CPUs during bringup before switching
>   * to the CPUs own pagetables.
> @@ -479,7 +483,7 @@ unsigned long domain_page_map_to_mfn(const void *ptr)
>      unsigned long offset = (va>>THIRD_SHIFT) & LPAE_ENTRY_MASK;
>  
>      if ( va >= VMAP_VIRT_START && va < VMAP_VIRT_END )
> -        return virt_to_mfn(va);
> +        return mfn_x(virt_to_mfn(va));

__virt_to_mfn?


>      ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
>      ASSERT(map[slot].pt.avail != 0);
> @@ -764,7 +768,7 @@ int init_secondary_pagetables(int cpu)
>       * domheap mapping pages. */
>      for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ )
>      {
> -        pte = mfn_to_xen_entry(_mfn(virt_to_mfn(domheap+i*LPAE_ENTRIES)),
> +        pte = mfn_to_xen_entry(virt_to_mfn(domheap+i*LPAE_ENTRIES),
>                                 WRITEALLOC);
>          pte.pt.table = 1;
>          
> write_pte(&first[first_table_offset(DOMHEAP_VIRT_START+i*FIRST_SIZE)], pte);
> @@ -961,7 +965,7 @@ static int create_xen_table(lpae_t *entry)
>      if ( p == NULL )
>          return -ENOMEM;
>      clear_page(p);
> -    pte = mfn_to_xen_entry(_mfn(virt_to_mfn(p)), WRITEALLOC);
> +    pte = mfn_to_xen_entry(virt_to_mfn(p), WRITEALLOC);
>      pte.pt.table = 1;
>      write_pte(entry, pte);
>      return 0;
> @@ -1216,7 +1220,7 @@ int xenmem_add_to_physmap_one(
>      unsigned long idx,
>      gfn_t gfn)
>  {
> -    unsigned long mfn = 0;
> +    mfn_t mfn = INVALID_MFN;
>      int rc;
>      p2m_type_t t;
>      struct page_info *page = NULL;
> @@ -1302,7 +1306,7 @@ int xenmem_add_to_physmap_one(
>              return -EINVAL;
>          }
>  
> -        mfn = page_to_mfn(page);
> +        mfn = _mfn(page_to_mfn(page));
>          t = p2m_map_foreign;
>  
>          rcu_unlock_domain(od);
> @@ -1321,7 +1325,7 @@ int xenmem_add_to_physmap_one(
>      }
>  
>      /* Map at new location. */
> -    rc = guest_physmap_add_entry(d, gfn, _mfn(mfn), 0, t);
> +    rc = guest_physmap_add_entry(d, gfn, mfn, 0, t);
>  
>      /* If we fail to add the mapping, we need to drop the reference we
>       * took earlier on foreign pages */
> diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
> index b2e7ea7761..6e2b3c7f2b 100644
> --- a/xen/include/asm-arm/mm.h
> +++ b/xen/include/asm-arm/mm.h
> @@ -264,7 +264,7 @@ static inline int gvirt_to_maddr(vaddr_t va, paddr_t *pa, 
> unsigned int flags)
>  #define __va(x)             (maddr_to_virt(x))
>  
>  /* Convert between Xen-heap virtual addresses and machine frame numbers. */
> -#define virt_to_mfn(va)   (virt_to_maddr(va) >> PAGE_SHIFT)
> +#define __virt_to_mfn(va) (virt_to_maddr(va) >> PAGE_SHIFT)
>  #define mfn_to_virt(mfn)  (maddr_to_virt((paddr_t)(mfn) << PAGE_SHIFT))
>  
>  /*
> @@ -274,6 +274,7 @@ static inline int gvirt_to_maddr(vaddr_t va, paddr_t *pa, 
> unsigned int flags)
>   */
>  #define mfn_to_page(mfn)    __mfn_to_page(mfn)
>  #define page_to_mfn(pg)     __page_to_mfn(pg)
> +#define virt_to_mfn(va)     __virt_to_mfn(va)
>  
>  /* Convert between Xen-heap virtual addresses and page-info structures. */
>  static inline struct page_info *virt_to_page(const void *v)
> -- 
> 2.11.0
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel