[RFC PATCH v2 3/3] tools, libxl: handle the iomem parameter with the memory_mapping hcall

[Arianna Avanzini <avanzini.arianna@gmail.com>]

Currently, the configuration-parsing code concerning the handling of the
iomem parameter only invokes the XEN_DOMCTL_iomem_permission hypercall.
This commit lets the XEN_DOMCTL_memory_mapping hypercall be invoked
after XEN_DOMCTL_iomem_permission when the iomem parameter is parsed
from a domU configuration file, so that the address range can be mapped
to the address space of the domU.
NOTE: the added code is still common to both x86 and ARM; it also
      implements a simple 1:1 mapping that could clash with the domU's
      existing memory layout if the range is already in use in the
      guest's address space.

Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Paolo Valente <paolo.valente@unimore.it>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Julien Grall <julien.grall@citrix.com>
Cc: Ian Campbell <Ian.Campbell@eu.citrix.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Eric Trudeau <etrudeau@broadcom.com>
Cc: Viktor Kleinik <viktor.kleinik@globallogic.com>
---
 tools/libxl/libxl_create.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index a604cd8..6c206c3 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -1099,6 +1099,23 @@ static void domcreate_launch_dm(libxl__egc *egc, libxl__multidev *multidev,
                  "failed give dom%d access to iomem range %"PRIx64"-%"PRIx64,
                  domid, io->start, io->start + io->number - 1);
             ret = ERROR_FAIL;
+        } else {
+            /*
+             * NOTE: the following code is still common to both x86
+             *       and ARM; it also implements a simple 1:1 mapping
+             *       that could clash with the domU's existing memory
+             *       layout if the range is already in use in the
+             *       guest's address space.
+             */
+            ret = xc_domain_memory_mapping(CTX->xch, domid,
+                                           io->start, io->start,
+                                           io->number, 1);
+            if (ret < 0) {
+                LOGE(ERROR,
+                     "failed to map to dom%d iomem range %"PRIx64"-%"PRIx64,
+                     domid, io->start, io->start + io->number - 1);
+                ret = ERROR_FAIL;
+            }
         }
     }
 
-- 
1.9.0