[PATCH v2 23/25] arm/altp2m: Extend libxl to activate altp2m on ARM.

[Sergej Proskurin <proskurin@sec.in.tum.de>]

The current implementation allows to set the parameter HVM_PARAM_ALTP2M.
This parameter allows further usage of altp2m on ARM. For this, we
define an additional, common altp2m field as part of the
libxl_domain_type struct. This field can be set on x86 and on ARM systems
through the "altp2m" switch in the domain's configuration file (i.e.
set altp2m=1).

Note, that the old parameter "altp2mhvm" is still valid for x86. Since
this commit defines this old parameter as deprecated, libxl will
generate a warning during processing.

Signed-off-by: Sergej Proskurin <proskurin@sec.in.tum.de>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
---
v2: The macro LIBXL_HAVE_ALTP2M is now valid for x86 and ARM.

    Moved the field altp2m out of info->u.pv.altp2m into the common
    field info->altp2m, where it can be accessed independent by the
    underlying architecture (x86 or ARM). Now, altp2m can be activated
    by the guest control parameter "altp2m".

    Adopted initialization routines accordingly.
---
 tools/libxl/libxl.h         |  3 ++-
 tools/libxl/libxl_create.c  |  8 +++++---
 tools/libxl/libxl_dom.c     |  4 ++--
 tools/libxl/libxl_types.idl |  4 +++-
 tools/libxl/xl_cmdimpl.c    | 26 +++++++++++++++++++++++++-
 5 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 48a43ce..a2cbd34 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -839,7 +839,8 @@ 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 and ARM PV guests.
  */
 #define LIBXL_HAVE_ALTP2M 1
 
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index d7db9e9..16d3b52 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -319,7 +319,6 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
         libxl_defbool_setdefault(&b_info->u.hvm.hpet,               true);
         libxl_defbool_setdefault(&b_info->u.hvm.vpt_align,          true);
         libxl_defbool_setdefault(&b_info->u.hvm.nested_hvm,         false);
-        libxl_defbool_setdefault(&b_info->u.hvm.altp2m,             false);
         libxl_defbool_setdefault(&b_info->u.hvm.usb,                false);
         libxl_defbool_setdefault(&b_info->u.hvm.xen_platform_pci,   true);
 
@@ -406,6 +405,9 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
             libxl_domain_type_to_string(b_info->type));
         return ERROR_INVAL;
     }
+
+    libxl_defbool_setdefault(&b_info->altp2m, false);
+
     return 0;
 }
 
@@ -901,8 +903,8 @@ static void initiate_domain_create(libxl__egc *egc,
 
     if (d_config->c_info.type == LIBXL_DOMAIN_TYPE_HVM &&
         (libxl_defbool_val(d_config->b_info.u.hvm.nested_hvm) &&
-         libxl_defbool_val(d_config->b_info.u.hvm.altp2m))) {
-        LOG(ERROR, "nestedhvm and altp2mhvm cannot be used together");
+         libxl_defbool_val(d_config->b_info.altp2m))) {
+        LOG(ERROR, "nestedhvm and altp2m cannot be used together");
         goto error_out;
     }
 
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index ec29060..1550ef8 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -291,8 +291,6 @@ static void hvm_set_conf_params(xc_interface *handle, uint32_t domid,
                     libxl_defbool_val(info->u.hvm.vpt_align));
     xc_hvm_param_set(handle, domid, HVM_PARAM_NESTEDHVM,
                     libxl_defbool_val(info->u.hvm.nested_hvm));
-    xc_hvm_param_set(handle, domid, HVM_PARAM_ALTP2M,
-                    libxl_defbool_val(info->u.hvm.altp2m));
 }
 
 int libxl__build_pre(libxl__gc *gc, uint32_t domid,
@@ -434,6 +432,8 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
 #endif
     }
 
+    xc_hvm_param_set(ctx->xch, domid, HVM_PARAM_ALTP2M, libxl_defbool_val(info->altp2m));
+
     rc = libxl__arch_domain_create(gc, d_config, domid);
 
     return rc;
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index ef614be..42e7c95 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -512,7 +512,6 @@ libxl_domain_build_info = Struct("domain_build_info",[
                                        ("mmio_hole_memkb",  MemKB),
                                        ("timer_mode",       libxl_timer_mode),
                                        ("nested_hvm",       libxl_defbool),
-                                       ("altp2m",           libxl_defbool),
                                        ("smbios_firmware",  string),
                                        ("acpi_firmware",    string),
                                        ("hdtype",           libxl_hdtype),
@@ -561,6 +560,9 @@ 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 PV guests.
+    ("altp2m", libxl_defbool),
 
     ], dir=DIR_IN
 )
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 51dc7a0..f4a49ee 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -1667,7 +1667,12 @@ static void parse_config_data(const char *config_source,
 
         xlu_cfg_get_defbool(config, "nestedhvm", &b_info->u.hvm.nested_hvm, 0);
 
-        xlu_cfg_get_defbool(config, "altp2mhvm", &b_info->u.hvm.altp2m, 0);
+        /* The config parameter "altp2mhvm" is considered deprecated, however
+         * further considered because of legacy reasons. The config parameter
+         * "altp2m" shall be used instead. */
+        if (!xlu_cfg_get_defbool(config, "altp2mhvm", &b_info->altp2m, 0))
+            fprintf(stderr, "WARNING: Specifying \"altp2mhvm\" is deprecated. "
+                    "Please use a \"altp2m\" instead.\n");
 
         xlu_cfg_replace_string(config, "smbios_firmware",
                                &b_info->u.hvm.smbios_firmware, 0);
@@ -1727,6 +1732,25 @@ static void parse_config_data(const char *config_source,
         abort();
     }
 
+    bool altp2m_support = false;
+#if defined(__i386__) || defined(__x86_64__)
+    /* Alternate p2m support on x86 is available only for HVM guests. */
+    if (b_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
+         * (only "altp2m" is accepted on ARM guests). If both parameters are
+         * given, it must be considered that the config parameter "altp2m" will
+         * always have priority over "altp2mhvm". */
+        xlu_cfg_get_defbool(config, "altp2m", &b_info->altp2m, 0);
+    }
+
     if (!xlu_cfg_get_list(config, "ioports", &ioports, &num_ioports, 0)) {
         b_info->num_ioports = num_ioports;
         b_info->ioports = calloc(num_ioports, sizeof(*b_info->ioports));
-- 
2.9.0


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