Re: [Xen-devel] [RFC PATCH 2/2] x86/mm: Add mem access rights to NPT

[Isaila Alexandru <aisaila@xxxxxxxxxxxxxxx>]

On Wed, 2018-09-26 at 17:47 +0100, George Dunlap wrote:
> From: Isaila Alexandru <aisaila@xxxxxxxxxxxxxxx>
> 
> This patch adds access control for NPT mode.
> 
> There aren’t enough extra bits to store the access rights in the NPT
> p2m
> table, so we add a radix tree to store extra information.
> 
> For efficiency:
>  - Only allocate this radix tree when we first store "non-default"
>    extra information
> 
>  - Remove entires which match the default extra information rather
>    than continuing to store them
> 
>  - For superpages, only store an entry for the first gfn in the
>    superpage.  Use the order of the p2m entry being read to determine
>    the proper place to look in the radix table.
> 
> Modify p2m_type_to_flags() to accept and interpret an access value,
> parallel to the ept code.
> 
> Add a set_default_access() method to the p2m-pt and p2m-ept versions
> of the p2m rather than setting it directly, to deal with different
> default permitted access values.
> 
> Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
> Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
> ---
> NB, this is compile-tested only.

I've tested this with xen-access and it works as expected
> 
> diff --git a/xen/arch/x86/monitor.c b/xen/arch/x86/monitor.c
> index 3c42e21906..2e6b1e75e4 100644
> --- a/xen/arch/x86/monitor.c
> +++ b/xen/arch/x86/monitor.c
> @@ -20,6 +20,7 @@
>   */
>  
>  #include <asm/monitor.h>
> +#include <asm/p2m.h>

Is this intended?

Regards,
Alex



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