Re: Xen PV IOMMU interface draft D

[Malcolm Crossley <malcolm.crossley@citrix.com>]

On 23/02/16 16:17, Jan Beulich wrote:
>>>> On 10.02.16 at 11:09, <malcolm.crossley@citrix.com> wrote:
>> % Xen PV IOMMU interface
>> % Malcolm Crossley <<malcolm.crossley@citrix.com>>
>>   Paul Durrant <<paul.durrant@citrix.com>>
>> % Draft D
>>
>> Introduction
>> ============
>>
>> Revision History
>> ----------------
>>
>> --------------------------------------------------------------------
>> Version  Date         Changes
>> -------  -----------  ----------------------------------------------
>> Draft A  10 Apr 2014  Initial draft.
>>
>> Draft B  12 Jun 2015  Second draft.
>>
>> Draft C  26 Jun 2015  Third draft.
>>
>> Draft D  09 Feb 2016  Fourth draft.
> 
> Unless this is a complete re-write, I'd really like to avoid needing to
> read through all of it again. Do you perhaps have a PDF version
> somewhere with change marks?
> 

It was really a minor update to ensure the design matched the RFC implementation.
The diff for the draft D is below. For the next revision I will details what has changed.

diff -r a35c08555541 -r e829e3d0fcec designs/pv-iommu-control/design.txt
--- a/designs/pv-iommu-control/design.txt
+++ b/designs/pv-iommu-control/design.txt
@@ -1,7 +1,7 @@
 % Xen PV IOMMU interface
 % Malcolm Crossley <<malcolm.crossley@citrix.com>>
   Paul Durrant <<paul.durrant@citrix.com>>
-% Draft C
+% Draft D

 Introduction
 ============
@@ -17,6 +17,8 @@ Draft A  10 Apr 2014  Initial draft.
 Draft B  12 Jun 2015  Second draft.

 Draft C  26 Jun 2015  Third draft.
+
+Draft D  09 Feb 2016  Fourth draft.
 --------------------------------------------------------------------

 Background
@@ -481,7 +483,9 @@ IOMMU_OP_readable            0        Cr
 IOMMU_OP_writeable           1        Create writeable IOMMU mapping
 IOMMU_MAP_OP_no_ref_cnt      2        IOMMU mapping does not take a reference to
                                       MFN backing BFN mapping
-Reserved for future use     3-9                   n/a
+IOMMU_MAP_OP_add_m2b         3        Wildcard M2B mapping added for
+                                      lookup_foreign_page to use
+Reserved for future use     4-9                   n/a
 IOMMU_page_order            10-15     Page order to be used for both gfn and bfn

 Defined values for map_page subop status field:
@@ -519,7 +523,9 @@ Defined bits for flags field:

 Name                        Bit                Definition
 ----                       -----      ----------------------------------
-Reserved for future use     0-9                   n/a
+IOMMU_UNMAP_OP_remove_m2b    0        Wildcard M2B mapping removed for
+                                      lookup_foreign_page use
+Reserved for future use     1-9                   n/a
 IOMMU_page_order            10-15     Page order to be used for bfn


Sorry about the hassle. I posted the RFC because I was would like to get some comments on the M2B
implementation and the iommu_lookup_page code.

Malcolm

> Jan
>