tools/libxl: parse optional start gfn from the iomem config option

Currently, the "iomem" domU config option allows to specify a machine
address range to be mapped to the domU. However, there is no way to
specify the guest address range used for the mapping. This commit
extends the iomem option handling code to parse an additional, optional
parameter: this parameter, if given, specifies the start guest address
used for the mapping; if no start guest address is given, a 1:1 mapping
is performed as default.

Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Ian Campbell <Ian.Campbell@eu.citrix.com>
Acked-by: Julien Grall <julien.grall@citrix.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Paolo Valente <paolo.valente@unimore.it>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Eric Trudeau <etrudeau@broadcom.com>
Cc: Viktor Kleinik <viktor.kleinik@globallogic.com>
Cc: Andrii Tseglytskyi <andrii.tseglytskyi@globallogic.com>

diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index f1fc906d0f00b5a31a4fde59bff1444c3ee2c371..517ae2fb92db9ce359a7eab9f61ac166077c793f 100644 (file)
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -670,12 +670,20 @@ is given in hexadecimal and may either a span e.g. C<2f8-2ff>
 It is recommended to use this option only for trusted VMs under
 administrator control.
 
-=item B<iomem=[ "IOMEM_START,NUM_PAGES", "IOMEM_START,NUM_PAGES", ... ]>
+=item B<iomem=[ "IOMEM_START,NUM_PAGES[@GFN]", "IOMEM_START,NUM_PAGES[@GFN]", ... ]>
 
-Allow guest to access specific hardware I/O memory pages. B<IOMEM_START>
-is a physical page number. B<NUM_PAGES> is the number
-of pages beginning with B<START_PAGE> to allow access. Both values
-must be given in hexadecimal.
+Allow auto-translated domains to access specific hardware I/O memory pages.
+
+B<IOMEM_START> is a physical page number. B<NUM_PAGES> is the number of pages
+beginning with B<START_PAGE> to allow access. B<GFN> specifies the guest frame
+number where the mapping will start in the domU's address space. If B<GFN> is
+not given, the mapping will be performed using B<IOMEM_START> as a start in the
+domU's address space, therefore performing an 1:1 mapping as default.
+All of these values must be given in hexadecimal.
+
+Note that the IOMMU won't be updated with the mappings specified with this
+option. This option therefore should not be used to passthrough any
+IOMMU-protected device.
 
 It is recommended to use this option only for trusted VMs under
 administrator control.

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index ded4ce503420b842c94757a4e1a5c2b10ab5ad8d..460207bf5948ee7ad548688cab66d6d23f65ff04 100644 (file)
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -127,6 +127,16 @@
  */
 #define LIBXL_HAVE_LIBXL_DEVICE_DISK_DISCARD_ENABLE 1
 
+/*
+ * LIBXL_HAVE_BUILDINFO_IOMEM_START_GFN indicates that it is possible
+ * to specify the start guest frame number used to map a range of I/O
+ * memory machine frame numbers via the 'gfn' field (of type uint64)
+ * of the 'iomem' structure. An array of iomem structures is embedded
+ * in libxl_domain_build_info and used to map the indicated memory
+ * ranges during domain build.
+ */
+#define LIBXL_HAVE_BUILDINFO_IOMEM_START_GFN 1
+
 /*
  * libxl ABI compatibility
  *

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index fc332ef551b2b4bcbe0c6f5ac36346ddd6e800aa..bc44ef5eda2fcbc484a699f20bfdc9e14efdf502 100644 (file)
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -102,6 +102,8 @@ static int sched_params_valid(libxl__gc *gc,
 int libxl__domain_build_info_setdefault(libxl__gc *gc,
                                         libxl_domain_build_info *b_info)
 {
+    int i;
+
     if (b_info->type != LIBXL_DOMAIN_TYPE_HVM &&
         b_info->type != LIBXL_DOMAIN_TYPE_PV)
         return ERROR_INVAL;
@@ -189,8 +191,6 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
 
     /* In libxl internals, we want to deal with vcpu_hard_affinity only! */
     if (b_info->cpumap.size && !b_info->num_vcpu_hard_affinity) {
-        int i;
-
         b_info->vcpu_hard_affinity = libxl__calloc(gc, b_info->max_vcpus,
                                                    sizeof(libxl_bitmap));
         for (i = 0; i < b_info->max_vcpus; i++) {
@@ -215,6 +215,10 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
 
     libxl_defbool_setdefault(&b_info->disable_migrate, false);
 
+    for (i = 0 ; i < b_info->num_iomem; i++)
+        if (b_info->iomem[i].gfn == LIBXL_INVALID_GFN)
+            b_info->iomem[i].gfn = b_info->iomem[i].start;
+
     if (!b_info->event_channels)
         b_info->event_channels = 1023;
 

diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index beb052e799c5639e1c75b40b0750af2ae085d2af..04c9378b53497a0b05d61473c64809b55d61cbfd 100644 (file)
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -91,6 +91,7 @@
 #define LIBXL_PV_EXTRA_MEMORY 1024
 #define LIBXL_HVM_EXTRA_MEMORY 2048
 #define LIBXL_MIN_DOM0_MEM (128*1024)
+#define LIBXL_INVALID_GFN (~(uint64_t)0)
 /* use 0 as the domid of the toolstack domain for now */
 #define LIBXL_TOOLSTACK_DOMID 0
 #define QEMU_SIGNATURE "DeviceModelRecord0002"

diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 08a79275bbc3aafb59c109b5aa2abcebfc136dff..931c9e96d0791dfc3fca571390ba266d3ff8f14e 100644 (file)
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -185,8 +185,12 @@ libxl_ioport_range = Struct("ioport_range", [
     ])
 
 libxl_iomem_range = Struct("iomem_range", [
+    # start host frame number to be mapped to the guest
     ("start", uint64),
+    # number of frames to be mapped
     ("number", uint64),
+    # guest frame number used as a start for the mapping
+    ("gfn", uint64, {'init_val': "LIBXL_INVALID_GFN"}),
     ])
 
 libxl_vga_interface_info = Struct("vga_interface_info", [

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 409a795268d900360bc1491db6cadaf7ed387952..e6b96154beba2bc1cf6259b2dc9c2719a49faa39 100644 (file)
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -1199,6 +1199,7 @@ static void parse_config_data(const char *config_source,
     }
 
     if (!xlu_cfg_get_list(config, "iomem", &iomem, &num_iomem, 0)) {
+        int ret;
         b_info->num_iomem = num_iomem;
         b_info->iomem = calloc(num_iomem, sizeof(*b_info->iomem));
         if (b_info->iomem == NULL) {
@@ -1212,13 +1213,15 @@ static void parse_config_data(const char *config_source,
                         "xl: Unable to get element %d in iomem list\n", i);
                 exit(1);
             }
-            if(sscanf(buf, "%" SCNx64",%" SCNx64,
-                     &b_info->iomem[i].start,
-                     &b_info->iomem[i].number)
-                  != 2) {
-               fprintf(stderr,
-                       "xl: Invalid argument parsing iomem: %s\n", buf);
-               exit(1);
+            libxl_iomem_range_init(&b_info->iomem[i]);
+            ret = sscanf(buf, "%" SCNx64",%" SCNx64"@%" SCNx64,
+                         &b_info->iomem[i].start,
+                         &b_info->iomem[i].number,
+                         &b_info->iomem[i].gfn);
+            if (ret < 2) {
+                fprintf(stderr,
+                        "xl: Invalid argument parsing iomem: %s\n", buf);
+                exit(1);
             }
         }
     }