Re: [Xen-devel] [for-4.7 2/2] xen/arm: Document the behavior of XENMAPSPACE_dev_mmio

2016-05-26 Thread Julien Grall 

Hi Stefano,

On 26/05/2016 10:18, Stefano Stabellini wrote:

On Wed, 25 May 2016, Julien Grall wrote:

On 25/05/16 14:14, Jan Beulich wrote:

Also - is Device_nGnRE a term uniform between ARM32 and ARM64?


Actually it should be Device-nGnRE to match with the spec. This has been
introduced on Armv8. Previously for Armv7, the name was "Device", although the
behavior is exactly the same.

I could say:

"ARM only; the region will be mapped in Stage-2 using the memory attribute
'Device-nGnRE' (previously named 'Device' on ARMv7)".


Small nit: I would say "the region gets mapped" or "is mapped" rather
than "will be" because that makes me think that it is a future behavior
of following Xen releases rather than the current behavior.


Good idea. I sent a v2 yesterday night [1]. So I will fix in the v3.


Acked-by: Stefano Stabellini 


[1] http://lists.xen.org/archives/html/xen-devel/2016-05/msg02490.html

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Re: [Xen-devel] [for-4.7 2/2] xen/arm: Document the behavior of XENMAPSPACE_dev_mmio

2016-05-26 Thread Stefano Stabellini 
On Wed, 25 May 2016, Julien Grall wrote:
> Hi Jan,
> 
> On 25/05/16 14:14, Jan Beulich wrote:
> > > > > On 25.05.16 at 13:41,  wrote:
> > > --- a/xen/include/public/memory.h
> > > +++ b/xen/include/public/memory.h
> > > @@ -220,7 +220,10 @@ DEFINE_XEN_GUEST_HANDLE(xen_machphys_mapping_t);
> > >   #define XENMAPSPACE_gmfn_range   3 /* GMFN range, XENMEM_add_to_physmap
> > > only. */
> > >   #define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another dom,
> > >   * XENMEM_add_to_physmap_batch only.
> > > */
> > > -#define XENMAPSPACE_dev_mmio 5 /* device mmio region */
> > > +#define XENMAPSPACE_dev_mmio 5 /* device mmio region
> > > +  On ARM, the region will be mapped
> > > +  in stage-2 using the memory
> > > attribute
> > > +  Device_nGnRE. */
> > 
> > Since this is unimplemented on x86, may I suggest to make this "ARM
> > only; the region will be ..."?
> 
> Sounds good.
> 
> > 
> > Also - is Device_nGnRE a term uniform between ARM32 and ARM64?
> 
> Actually it should be Device-nGnRE to match with the spec. This has been
> introduced on Armv8. Previously for Armv7, the name was "Device", although the
> behavior is exactly the same.
> 
> I could say:
> 
> "ARM only; the region will be mapped in Stage-2 using the memory attribute
> 'Device-nGnRE' (previously named 'Device' on ARMv7)".

Small nit: I would say "the region gets mapped" or "is mapped" rather
than "will be" because that makes me think that it is a future behavior
of following Xen releases rather than the current behavior.

Acked-by: Stefano Stabellini 

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Re: [Xen-devel] [for-4.7 2/2] xen/arm: Document the behavior of XENMAPSPACE_dev_mmio

2016-05-25 Thread Jan Beulich 
>>> On 25.05.16 at 16:43,  wrote:
> I could say:
> 
> "ARM only; the region will be mapped in Stage-2 using the memory 
> attribute 'Device-nGnRE' (previously named 'Device' on ARMv7)".

SGTM

Jan


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Re: [Xen-devel] [for-4.7 2/2] xen/arm: Document the behavior of XENMAPSPACE_dev_mmio

2016-05-25 Thread Julien Grall 

Hi Jan,

On 25/05/16 14:14, Jan Beulich wrote:

On 25.05.16 at 13:41,  wrote:

--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -220,7 +220,10 @@ DEFINE_XEN_GUEST_HANDLE(xen_machphys_mapping_t);
  #define XENMAPSPACE_gmfn_range   3 /* GMFN range, XENMEM_add_to_physmap only. 
*/
  #define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another dom,
  * XENMEM_add_to_physmap_batch only. */
-#define XENMAPSPACE_dev_mmio 5 /* device mmio region */
+#define XENMAPSPACE_dev_mmio 5 /* device mmio region
+  On ARM, the region will be mapped
+  in stage-2 using the memory attribute
+  Device_nGnRE. */


Since this is unimplemented on x86, may I suggest to make this "ARM
only; the region will be ..."?


Sounds good.



Also - is Device_nGnRE a term uniform between ARM32 and ARM64?


Actually it should be Device-nGnRE to match with the spec. This has been 
introduced on Armv8. Previously for Armv7, the name was "Device", 
although the behavior is exactly the same.


I could say:

"ARM only; the region will be mapped in Stage-2 using the memory 
attribute 'Device-nGnRE' (previously named 'Device' on ARMv7)".


Regards,

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Re: [Xen-devel] [for-4.7 2/2] xen/arm: Document the behavior of XENMAPSPACE_dev_mmio

2016-05-25 Thread Jan Beulich 
>>> On 25.05.16 at 13:41,  wrote:
> --- a/xen/include/public/memory.h
> +++ b/xen/include/public/memory.h
> @@ -220,7 +220,10 @@ DEFINE_XEN_GUEST_HANDLE(xen_machphys_mapping_t);
>  #define XENMAPSPACE_gmfn_range   3 /* GMFN range, XENMEM_add_to_physmap 
> only. */
>  #define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another dom,
>  * XENMEM_add_to_physmap_batch only. */
> -#define XENMAPSPACE_dev_mmio 5 /* device mmio region */
> +#define XENMAPSPACE_dev_mmio 5 /* device mmio region
> +  On ARM, the region will be mapped
> +  in stage-2 using the memory attribute
> +  Device_nGnRE. */

Since this is unimplemented on x86, may I suggest to make this "ARM
only; the region will be ..."?

Also - is Device_nGnRE a term uniform between ARM32 and ARM64?

Jan


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[Xen-devel] [for-4.7 2/2] xen/arm: Document the behavior of XENMAPSPACE_dev_mmio

2016-05-25 Thread Julien Grall 
Currently, XENMAPSPACE_dev_mmio maps MMIO regions using one of the most
restrictive memory attribute (Device_nGnRE).

Signed-off-by: Julien Grall 
---
 xen/include/public/memory.h | 5 -
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index b023046..ece72d2 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -220,7 +220,10 @@ DEFINE_XEN_GUEST_HANDLE(xen_machphys_mapping_t);
 #define XENMAPSPACE_gmfn_range   3 /* GMFN range, XENMEM_add_to_physmap only. 
*/
 #define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another dom,
 * XENMEM_add_to_physmap_batch only. */
-#define XENMAPSPACE_dev_mmio 5 /* device mmio region */
+#define XENMAPSPACE_dev_mmio 5 /* device mmio region
+  On ARM, the region will be mapped
+  in stage-2 using the memory attribute
+  Device_nGnRE. */
 /* ` } */
 
 /*
-- 
1.9.1


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