On Fri, 7 Aug 2015, Julien Grall wrote:
> The Xen hypercall interface is always using 4K page granularity on ARM
> and x86 architecture.
>
> With the incoming support of 64K page granularity for ARM64 guest, it
> won't be possible to re-use the Linux page definition in Xen drivers.
>
> Introduce Xen page definition helpers based on the Linux page
> definition. They have exactly the same name but prefixed with
> XEN_/xen_ prefix.
>
> Also modify xen_page_to_gfn to use new Xen page definition.
>
> Signed-off-by: Julien Grall <julien.gr...@citrix.com>
> Reviewed-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
>
> ---
> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
> Cc: David Vrabel <david.vra...@citrix.com>
>
> Changes in v3:
> - Fix errors reported by checkpatch.pl
> - Rename pfn to xen_pfn in xen_pfn_to_page
> - Add a comment that we assume PAGE_SIZE to be a multiple of
> XEN_PAGE_SIZE
> - s/MFN/GFN/ according to new naming
> - Add Stefano's reviewed-by
>
> Changes in v2:
> - Add XEN_PFN_UP
> - Add a comment describing the behavior of page_to_pfn
> ---
> include/xen/page.h | 27 ++++++++++++++++++++++++++-
> 1 file changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/include/xen/page.h b/include/xen/page.h
> index f202992..dac1b26 100644
> --- a/include/xen/page.h
> +++ b/include/xen/page.h
> @@ -1,11 +1,36 @@
> #ifndef _XEN_PAGE_H
> #define _XEN_PAGE_H
>
> +#include <asm/page.h>
> +
> +/* The hypercall interface supports only 4KB page */
> +#define XEN_PAGE_SHIFT 12
> +#define XEN_PAGE_SIZE (_AC(1, UL) << XEN_PAGE_SHIFT)
> +#define XEN_PAGE_MASK (~(XEN_PAGE_SIZE-1))
> +#define xen_offset_in_page(p) ((unsigned long)(p) & ~XEN_PAGE_MASK)
> +
> +/*
> + * We asume that PAGE_SIZE is a multiple of XEN_PAGE_SIZE
^ assume
> + * XXX: Add a BUILD_BUG_ON?
> + */
> +
> +#define xen_pfn_to_page(xen_pfn) \
> + ((pfn_to_page(((unsigned long)(xen_pfn) << XEN_PAGE_SHIFT) >>
> PAGE_SHIFT)))
> +#define xen_page_to_pfn(page) \
> + (((page_to_pfn(page)) << PAGE_SHIFT) >> XEN_PAGE_SHIFT)
> +
> +#define XEN_PFN_PER_PAGE (PAGE_SIZE / XEN_PAGE_SIZE)
> +
> +#define XEN_PFN_DOWN(x) ((x) >> XEN_PAGE_SHIFT)
> +#define XEN_PFN_UP(x) (((x) + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT)
> +#define XEN_PFN_PHYS(x) ((phys_addr_t)(x) << XEN_PAGE_SHIFT)
> +
> #include <asm/xen/page.h>
>
> +/* Return the GFN associated to the first 4KB of the page */
> static inline unsigned long xen_page_to_gfn(struct page *page)
> {
> - return pfn_to_gfn(page_to_pfn(page));
> + return pfn_to_gfn(xen_page_to_pfn(page));
> }
>
> struct xen_memory_region {
> --
> 2.1.4
>
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