Re: [Xen-devel] [PATCH 1/4] expand x86 arch_shared_info to support linear p2m list

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.11.14 at 10:37, <"jgross@xxxxxxxx".non-mime.internet> wrote:
> --- a/xen/include/public/arch-x86/xen.h
> +++ b/xen/include/public/arch-x86/xen.h
> @@ -224,7 +224,12 @@ struct arch_shared_info {
>      /* Frame containing list of mfns containing list of mfns containing p2m. 
> */
>      xen_pfn_t     pfn_to_mfn_frame_list_list;
>      unsigned long nmi_reason;
> -    uint64_t pad[32];
> +    /*
> +     * Following two fields are valid if pfn_to_mfn_frame_list_list contains
> +     * ~0UL.
> +     */
> +    unsigned long p2m_vaddr;    /* virtual address of the p2m list */
> +    unsigned long p2m_as_root;  /* mfn of the top level page table */

xen_pfn_t please. And what does the "as" in the name stand for?
It's also kind of unclear in the description what "the page table root"
is, as I don't think there are many OSes which use just a single set
of page tables (i.e. just a single address space). Not having followed
the discussion closely - what is this needed for anyway?

> --- a/xen/include/public/features.h
> +++ b/xen/include/public/features.h
> @@ -99,6 +99,9 @@
>  #define XENFEAT_grant_map_identity        12
>   */
>  
> +/* x86: guest may specify virtual address of p2m list */
> +#define XENFEAT_virtual_p2m               13

The name to me suggests something that's not real. Perhaps better
XENFEAT_virtually_mapped_p2m or XENFEAT_p2m_va{,ddr}?

Jan


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