Re: [Xen-devel] [PATCH for-next 02/16] xen/arm: raw_copy_to_guest_helper: Rework the prototype and rename it

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 23 Nov 2017, Julien Grall wrote:
> All the helpers within arch/arm/guestcopy.c are doing the same things:
> copy data from/to the guest.
> 
> At the moment, the logic is duplicated in each helpers making more
> difficult to implement new variant.
> 
> The first step for the consolidation is to get a common prototype and a
> base. For convenience (it is at the beginning of the file!),
> raw_copy_to_guest_helper is chosen.
> 
> The function is now renamed copy_guest to show it will be a
> generic function to copy data from/to the guest. Note that for now, only
> copying to guest virtual address is supported. Follow-up patches will
> extend the support.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> ---
>  xen/arch/arm/guestcopy.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/xen/arch/arm/guestcopy.c b/xen/arch/arm/guestcopy.c
> index 2620e659b4..d1cfbe922c 100644
> --- a/xen/arch/arm/guestcopy.c
> +++ b/xen/arch/arm/guestcopy.c
> @@ -7,11 +7,11 @@
>  
>  #define COPY_flush_dcache   (1U << 0)
>  
> -static unsigned long raw_copy_to_guest_helper(void *to, const void *from,
> -                                              unsigned len, int flags)
> +static unsigned long copy_guest(void *buf, paddr_t addr, unsigned int len,
> +                                unsigned int flags)

Why not use vaddr_t ?


>  {
>      /* XXX needs to handle faults */
> -    unsigned offset = (vaddr_t)to & ~PAGE_MASK;
> +    unsigned offset = addr & ~PAGE_MASK;
>  
>      while ( len )
>      {
> @@ -19,21 +19,21 @@ static unsigned long raw_copy_to_guest_helper(void *to, 
> const void *from,
>          unsigned size = min(len, (unsigned)PAGE_SIZE - offset);
>          struct page_info *page;
>  
> -        page = get_page_from_gva(current, (vaddr_t) to, GV2M_WRITE);
> +        page = get_page_from_gva(current, addr, GV2M_WRITE);
>          if ( page == NULL )
>              return len;
>  
>          p = __map_domain_page(page);
>          p += offset;
> -        memcpy(p, from, size);
> +        memcpy(p, buf, size);
>          if ( flags & COPY_flush_dcache )
>              clean_dcache_va_range(p, size);
>  
>          unmap_domain_page(p - offset);
>          put_page(page);
>          len -= size;
> -        from += size;
> -        to += size;
> +        buf += size;
> +        addr += size;
>          /*
>           * After the first iteration, guest virtual address is correctly
>           * aligned to PAGE_SIZE.
> @@ -46,13 +46,13 @@ static unsigned long raw_copy_to_guest_helper(void *to, 
> const void *from,
>  
>  unsigned long raw_copy_to_guest(void *to, const void *from, unsigned len)
>  {
> -    return raw_copy_to_guest_helper(to, from, len, 0);
> +    return copy_guest((void *)from, (unsigned long)to, len, 0);
>  }
>  
>  unsigned long raw_copy_to_guest_flush_dcache(void *to, const void *from,
>                                               unsigned len)
>  {
> -    return raw_copy_to_guest_helper(to, from, len, COPY_flush_dcache);
> +    return copy_guest((void *)from, (unsigned long)to, len, 
> COPY_flush_dcache);
>  }
>  
>  unsigned long raw_clear_guest(void *to, unsigned len)
> -- 
> 2.11.0
> 

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