[PATCH v4 02/14] xen/arm: xc_domain_ioport_permission(..) not supported on ARM.

[Rahul Singh <rahul.singh@xxxxxxx>]

ARM architecture does not implement I/O ports. Ignore this call on ARM
to avoid the overhead of making a hypercall just for Xen to return
-ENOSYS.

Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
Change in v4:
- Added Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
Change in v3: Added Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Change in v2:
- Instead of returning success in XEN, ignored the call in xl.
---
---
 tools/libs/ctrl/xc_domain.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/libs/ctrl/xc_domain.c b/tools/libs/ctrl/xc_domain.c
index 23322b70b5..25c95f6596 100644
--- a/tools/libs/ctrl/xc_domain.c
+++ b/tools/libs/ctrl/xc_domain.c
@@ -1348,6 +1348,14 @@ int xc_domain_ioport_permission(xc_interface *xch,
                                 uint32_t nr_ports,
                                 uint32_t allow_access)
 {
+#if defined(__arm__) || defined(__aarch64__)
+    /*
+     * The ARM architecture does not implement I/O ports.
+     * Avoid the overhead of making a hypercall just for Xen to return -ENOSYS.
+     * It is safe to ignore this call on ARM so we just return 0.
+     */
+    return 0;
+#else
     DECLARE_DOMCTL;
 
     domctl.cmd = XEN_DOMCTL_ioport_permission;
@@ -1357,6 +1365,7 @@ int xc_domain_ioport_permission(xc_interface *xch,
     domctl.u.ioport_permission.allow_access = allow_access;
 
     return do_domctl(xch, &domctl);
+#endif
 }
 
 int xc_availheap(xc_interface *xch,
-- 
2.25.1