Re: [Xen-devel] [PATCH] public/elfnote: document non-alignment of relocated init-P2M

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 09/05/17 15:23, Jan Beulich wrote:
> Since PV kernels can't use large pages anywa, when the init-P2M support

anyway

~Andrew

> was added it was decided to keep the implementation simple and not
> align large pages in PFN space. Document this.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/include/public/elfnote.h
> +++ b/xen/include/public/elfnote.h
> @@ -173,7 +173,9 @@
>   * The (non-default) location the initial phys-to-machine map should be
>   * placed at by the hypervisor (Dom0) or the tools (DomU).
>   * The kernel must be prepared for this mapping to be established using
> - * large pages, despite such otherwise not being available to guests.
> + * large pages, despite such otherwise not being available to guests. Note
> + * that these large pages may be misaligned in PFN space (they'll obviously
> + * be aligned in MFN and virtual address spaces).
>   * The kernel must also be able to handle the page table pages used for
>   * this mapping not being accessible through the initial mapping.
>   * (Only x86-64 supports this at present.)
>
>
>


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