Re: [Xen-devel] [PATCH v7 07/14] xen/arm: map_regions_rw_cache: Map the region with p2m->default_access

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 12 Jul 2016, Julien Grall wrote:
> The parameter 'access' is used by memaccess to restrict temporarily the
> permission. This parameter should not be used for other purpose (such
> as restricting permanently the permission).
> 
> Instead, we should use the default access requested by memacess. When it
> is not enabled, the access will be p2m_access_rwx (i.e no restriction
> applied).
> 
> The type p2m_mmio_direct will map the region read-write and
> non-executable before any further restriction by memaccess. Note that
> this is already the resulting permission with the curreent combination
> of the type and the access. So there is no functional change.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> Cc: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> 
>     This patch is a candidate for Xen 4.7. Currently this function is
>     only used to map ACPI regions.
> 
>     I am wondering if we should introduce a new p2m type for it. And map
>     this region RO (I am not sure why a guest would want to
>     modify this region).
> 
>     Changes in v2:
>         - Reword the commit message
> 
>     Changes in v4:
>         - Patch added
> ---
>  xen/arch/arm/p2m.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 1cfb62b..fcc4513 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -1231,7 +1231,7 @@ int map_regions_rw_cache(struct domain *d,
>                               pfn_to_paddr(start_gfn + nr),
>                               pfn_to_paddr(mfn),
>                               MATTR_MEM, 0, p2m_mmio_direct,
> -                             p2m_access_rw);
> +                             d->arch.p2m.default_access);
>  }
>  
>  int unmap_regions_rw_cache(struct domain *d,
> @@ -1244,7 +1244,7 @@ int unmap_regions_rw_cache(struct domain *d,
>                               pfn_to_paddr(start_gfn + nr),
>                               pfn_to_paddr(mfn),
>                               MATTR_MEM, 0, p2m_invalid,
> -                             p2m_access_rw);
> +                             d->arch.p2m.default_access);
>  }
>  
>  int map_mmio_regions(struct domain *d,
> -- 
> 1.9.1
> 

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