[Xen-devel] [PATCH v4 37/39] altp2m: Allow activating altp2m on ARM domains

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

The previous libxl implemention limited the use of altp2m to x86 HVM domains.
This commit extends libxl by introducing the altp2m switch to ARM domains.

Additionally, we introduce the macro LIBXL_HAVE_ARM_ALTP2M in parallel to the
former LIBXL_HAVE_ALTP2M to differentiate between altp2m for x86 and and altp2m
for ARM architectures. We also extend the documentation of the option "altp2m"
in ./docs/man/xl.cfg.pod.5.in.

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/libxl/libxl.h         | 10 +++++++++-
 tools/libxl/libxl_dom.c     | 16 ++++++++++++++--
 tools/libxl/libxl_types.idl |  2 +-
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 17045253ab..e7af15bc45 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -872,11 +872,19 @@ typedef struct libxl__ctx libxl_ctx;
 
 /*
  * LIBXL_HAVE_ALTP2M
- * If this is defined, then libxl supports alternate p2m functionality.
+ * If this is defined, then libxl supports alternate p2m functionality for
+ * x86 HVM guests.
  */
 #define LIBXL_HAVE_ALTP2M 1
 
 /*
+ * LIBXL_HAVE_ARM_ALTP2M
+ * If this is defined, then libxl supports alternate p2m functionality for
+ * ARM guests.
+ */
+#define LIBXL_HAVE_ARM_ALTP2M 1
+
+/*
  * LIBXL_HAVE_REMUS
  * If this is defined, then libxl supports remus.
  */
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index f54fd49a73..db77c95a7e 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -314,6 +314,7 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
     libxl_domain_build_info *const info = &d_config->b_info;
     libxl_ctx *ctx = libxl__gc_owner(gc);
     char *xs_domid, *con_domid;
+    bool altp2m_support = false;
     int rc;
     uint64_t size;
 
@@ -458,18 +459,29 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
 #endif
     }
 
+#if defined(__i386__) || defined(__x86_64__)
     /* Alternate p2m support on x86 is available only for HVM guests. */
-    if (info->type == LIBXL_DOMAIN_TYPE_HVM) {
+    if (info->type == LIBXL_DOMAIN_TYPE_HVM)
+        altp2m_support = true;
+#elif defined(__arm__) || defined(__aarch64__)
+    /* Alternate p2m support on ARM is available for all guests. */
+    altp2m_support = true;
+#endif
+
+    if (altp2m_support) {
         /* The config parameter "altp2m" replaces the parameter "altp2mhvm". 
For
-         * legacy reasons, both parameters are accepted on x86 HVM guests.
+         * legacy reasons, both parameters are accepted on x86 HVM guests (only
+         * "altp2m" is accepted on ARM guests).
          *
          * If the legacy field info->u.hvm.altp2m is set, activate altp2m.
          * Otherwise set altp2m based on the field info->altp2m. */
+#if defined(__i386__) || defined(__x86_64__)
         if (info->altp2m == LIBXL_ALTP2M_MODE_DISABLED &&
             libxl_defbool_val(info->u.hvm.altp2m))
             xc_hvm_param_set(ctx->xch, domid, HVM_PARAM_ALTP2M,
                              libxl_defbool_val(info->u.hvm.altp2m));
         else
+#endif
             xc_hvm_param_set(ctx->xch, domid, HVM_PARAM_ALTP2M,
                              info->altp2m);
     }
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 6e80d36256..412a0b6129 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -583,7 +583,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
     ("arch_arm", Struct(None, [("gic_version", libxl_gic_version),
                               ])),
     # Alternate p2m is not bound to any architecture or guest type, as it is
-    # supported by x86 HVM and ARM support is planned.
+    # supported by x86 HVM and ARM domains.
     ("altp2m", libxl_altp2m_mode),
 
     ], dir=DIR_IN
-- 
2.13.3


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel