[PATCH V5 03/22] x86/ioreq: Provide out-of-line wrapper for the handle_mmio()

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

The IOREQ is about to be common feature and Arm will have its own
implementation.

But the name of the function is pretty generic and can be confusing
on Arm (we already have a try_handle_mmio()).

In order not to rename the function (which is used for a varying
set of purposes on x86) globally and get non-confusing variant on Arm
provide a wrapper arch_ioreq_complete_mmio() to be used on common
and Arm code.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Paul Durrant <paul@xen.org>
CC: Julien Grall <julien.grall@arm.com>
[On Arm only]
Tested-by: Wei Chen <Wei.Chen@arm.com>

---
Please note, this is a split/cleanup/hardening of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"

Changes RFC -> V1:
   - new patch

Changes V1 -> V2:
   - remove "handle"
   - add Jan's A-b

Changes V2 -> V3:
   - remove Jan's A-b
   - update patch subject/description
   - use out-of-line function instead of #define
   - put earlier in the series to avoid breakage

Changes V3 -> V4:
   - add Jan's R-b
   - rename ioreq_complete_mmio() to arch_ioreq_complete_mmio()

Changes V4 -> V5:
   - rebase
   - add Alex's, Julien's and Paul's R-b
---
---
 xen/arch/x86/hvm/ioreq.c | 7 ++++++-
 xen/include/xen/ioreq.h  | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
index 27a4a6f..30e8724 100644
--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -36,6 +36,11 @@
 #include <public/hvm/ioreq.h>
 #include <public/hvm/params.h>
 
+bool arch_ioreq_complete_mmio(void)
+{
+    return handle_mmio();
+}
+
 static void set_ioreq_server(struct domain *d, unsigned int id,
                              struct hvm_ioreq_server *s)
 {
@@ -226,7 +231,7 @@ bool handle_hvm_io_completion(struct vcpu *v)
         break;
 
     case HVMIO_mmio_completion:
-        return handle_mmio();
+        return arch_ioreq_complete_mmio();
 
     case HVMIO_pio_completion:
         return handle_pio(vio->io_req.addr, vio->io_req.size,
diff --git a/xen/include/xen/ioreq.h b/xen/include/xen/ioreq.h
index d0980c5..b95d3ef 100644
--- a/xen/include/xen/ioreq.h
+++ b/xen/include/xen/ioreq.h
@@ -24,6 +24,7 @@
 #define HANDLE_BUFIOREQ(s) \
     ((s)->bufioreq_handling != HVM_IOREQSRV_BUFIOREQ_OFF)
 
+bool arch_ioreq_complete_mmio(void);
 bool arch_vcpu_ioreq_completion(enum hvm_io_completion io_completion);
 int arch_ioreq_server_map_pages(struct hvm_ioreq_server *s);
 void arch_ioreq_server_unmap_pages(struct hvm_ioreq_server *s);
-- 
2.7.4