[Xen-devel] [PATCH 3/6] libxl/xl: add cacheability option to iomem

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Parse a new cacheability option for the iomem parameter, it can be
"devmem" for device memory mappings, which is the default, or "memory"
for normal memory mappings.

Store the parameter in a new field in libxl_iomem_range.

Pass the cacheability option to xc_domain_memory_mapping.

Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
CC: ian.jackson@xxxxxxxxxxxxx
CC: wei.liu2@xxxxxxxxxx
---
 docs/man/xl.cfg.pod.5.in    |  4 +++-
 tools/libxl/libxl_create.c  | 12 +++++++++++-
 tools/libxl/libxl_types.idl |  7 +++++++
 tools/xl/xl_parse.c         | 17 +++++++++++++++--
 4 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/docs/man/xl.cfg.pod.5.in b/docs/man/xl.cfg.pod.5.in
index b1c0be1..655008a 100644
--- a/docs/man/xl.cfg.pod.5.in
+++ b/docs/man/xl.cfg.pod.5.in
@@ -1222,7 +1222,7 @@ is given in hexadecimal format and may either be a range, 
e.g. C<2f8-2ff>
 It is recommended to only use this option for trusted VMs under
 administrator's control.
 
-=item B<iomem=[ "IOMEM_START,NUM_PAGES[@GFN]", "IOMEM_START,NUM_PAGES[@GFN]", 
...]>
+=item B<iomem=[ "IOMEM_START,NUM_PAGES[@GFN],CACHEABILITY", 
"IOMEM_START,NUM_PAGES[@GFN],CACHEABILITY", ...]>
 
 Allow auto-translated domains to access specific hardware I/O memory pages.
 
@@ -1233,6 +1233,8 @@ B<GFN> is not specified, the mapping will be performed 
using B<IOMEM_START>
 as a start in the guest's address space, therefore performing a 1:1 mapping
 by default.
 All of these values must be given in hexadecimal format.
+B<CACHEABILITY> can be "devmem" for device memory, the default if not
+specified, or it can be "memory" for normal memory.
 
 Note that the IOMMU won't be updated with the mappings specified with this
 option. This option therefore should not be used to pass through any
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 9a9b953..15edf1c 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -415,6 +415,14 @@ static void init_console_info(libxl__gc *gc,
        Only 'channels' when mapped to consoles have a string name. */
 }
 
+static uint32_t libxl__cacheability_to_xc(libxl_cacheability c)
+{
+    if (c == LIBXL_CACHEABILITY_MEMORY)
+        return CACHEABILITY_MEMORY;
+    /* default to devmem */
+    return CACHEABILITY_DEVMEM;
+}
+
 int libxl__domain_build(libxl__gc *gc,
                         libxl_domain_config *d_config,
                         uint32_t domid,
@@ -1348,7 +1356,9 @@ static void domcreate_launch_dm(libxl__egc *egc, 
libxl__multidev *multidev,
         }
         ret = xc_domain_memory_mapping(CTX->xch, domid,
                                        io->gfn, io->start,
-                                       io->number, 1, CACHEABILITY_DEVMEM);
+                                       io->number, 1,
+                                       libxl__cacheability_to_xc(
+                                           io->cache_policy));
         if (ret < 0) {
             LOGED(ERROR, domid,
                   "failed to map to domain iomem range %"PRIx64"-%"PRIx64
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 3b8f967..897c539 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -262,6 +262,11 @@ libxl_ioport_range = Struct("ioport_range", [
     ("number", uint32),
     ])
 
+libxl_cacheability = Enumeration("cacheability", [
+    (0, "devmem"),
+    (1, "memory"),
+    ], init_val = "LIBXL_CACHEABILITY_DEVMEM")
+
 libxl_iomem_range = Struct("iomem_range", [
     # start host frame number to be mapped to the guest
     ("start", uint64),
@@ -269,6 +274,8 @@ libxl_iomem_range = Struct("iomem_range", [
     ("number", uint64),
     # guest frame number used as a start for the mapping
     ("gfn", uint64, {'init_val': "LIBXL_INVALID_GFN"}),
+    # cacheability of the memory region
+    ("cache_policy", libxl_cacheability),
     ])
 
 libxl_vga_interface_info = Struct("vga_interface_info", [
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index 352cd21..1da2670 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -1883,6 +1883,7 @@ void parse_config_data(const char *config_source,
         }
         for (i = 0; i < num_iomem; i++) {
             int used;
+            char cache[7];
 
             buf = xlu_cfg_get_listitem (iomem, i);
             if (!buf) {
@@ -1891,15 +1892,27 @@ void parse_config_data(const char *config_source,
                 exit(1);
             }
             libxl_iomem_range_init(&b_info->iomem[i]);
-            ret = sscanf(buf, "%" SCNx64",%" SCNx64"%n@%" SCNx64"%n",
+            ret = sscanf(buf, "%" SCNx64",%" SCNx64"%n@%" SCNx64"%n,%6s%n",
                          &b_info->iomem[i].start,
                          &b_info->iomem[i].number, &used,
-                         &b_info->iomem[i].gfn, &used);
+                         &b_info->iomem[i].gfn, &used,
+                         cache, &used);
             if (ret < 2 || buf[used] != '\0') {
                 fprintf(stderr,
                         "xl: Invalid argument parsing iomem: %s\n", buf);
                 exit(1);
             }
+            if (ret == 4) {
+                if (!strcmp(cache, "memory"))
+                    b_info->iomem[i].cache_policy = LIBXL_CACHEABILITY_MEMORY;
+                else if (!strcmp(cache, "devmem"))
+                    b_info->iomem[i].cache_policy = LIBXL_CACHEABILITY_DEVMEM;
+                else {
+                    fprintf(stderr,
+                            "xl: Invalid iomem cache parameter: %s\n", cache);
+                    exit(1);
+                }
+            }
         }
     }
 
-- 
1.9.1


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