RE: [PATCH V5 09/22] xen/ioreq: Make x86's IOREQ related dm-op handling common

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>
> Sent: 25 January 2021 19:08
> To: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Julien Grall <julien.grall@xxxxxxx>; Jan Beulich <jbeulich@xxxxxxxx>; 
> Andrew Cooper
> <andrew.cooper3@xxxxxxxxxx>; Roger Pau Monné <roger.pau@xxxxxxxxxx>; Wei Liu 
> <wl@xxxxxxx>; George
> Dunlap <george.dunlap@xxxxxxxxxx>; Ian Jackson <iwj@xxxxxxxxxxxxxx>; Julien 
> Grall <julien@xxxxxxx>;
> Stefano Stabellini <sstabellini@xxxxxxxxxx>; Paul Durrant <paul@xxxxxxx>; 
> Daniel De Graaf
> <dgdegra@xxxxxxxxxxxxx>; Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> Subject: [PATCH V5 09/22] xen/ioreq: Make x86's IOREQ related dm-op handling 
> common
> 
> From: Julien Grall <julien.grall@xxxxxxx>
> 
> As a lot of x86 code can be re-used on Arm later on, this patch
> moves the IOREQ related dm-op handling to the common code.
> 
> The idea is to have the top level dm-op handling arch-specific
> and call into ioreq_server_dm_op() for otherwise unhandled ops.
> Pros:
> - More natural than doing it other way around (top level dm-op
> handling common).
> - Leave compat_dm_op() in x86 code.
> Cons:
> - Code duplication. Both arches have to duplicate dm_op(), etc.
> 
> Make the corresponding functions static and rename them according
> to the new naming scheme (including dropping the "hvm" prefixes).
> 
> Introduce common dm.c file as a resting place for the do_dm_op()
> (which is identical for both Arm and x86) to minimize code duplication.
> The common DM feature is supposed to be built with IOREQ_SERVER
> option enabled (as well as the IOREQ feature), which is selected
> for x86's config HVM for now.
> 
> Also update XSM code a bit to let dm-op be used on Arm.
> 
> This support is going to be used on Arm to be able run device
> emulator outside of Xen hypervisor.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
> [On Arm only]
> Tested-by: Wei Chen <Wei.Chen@xxxxxxx>
> 

Reviewed-by: Paul Durrant <paul@xxxxxxx>