[Xen-devel] [PATCH 01/18] arm/altp2m: Add cmd-line support for altp2m on ARM.

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

The Xen altp2m subsystem is currently supported only on x86-64 based
architectures. By utilizing ARM's virtualization extensions, we intend
to implement altp2m support for ARM architectures and thus further
extend current Virtual Machine Introspection (VMI) capabilities on ARM.

With this commit, Xen is now able to activate altp2m support on ARM by
means of the command-line argument 'altp2m' (bool).

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/hvm.c            | 22 ++++++++++++++++++++
 xen/include/asm-arm/hvm/hvm.h | 47 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 xen/include/asm-arm/hvm/hvm.h

diff --git a/xen/arch/arm/hvm.c b/xen/arch/arm/hvm.c
index d999bde..3615036 100644
--- a/xen/arch/arm/hvm.c
+++ b/xen/arch/arm/hvm.c
@@ -32,6 +32,28 @@
 
 #include <asm/hypercall.h>
 
+#include <asm/hvm/hvm.h>
+
+/* Xen command-line option enabling altp2m */
+static bool_t __initdata opt_altp2m_enabled = 0;
+boolean_param("altp2m", opt_altp2m_enabled);
+
+struct hvm_function_table hvm_funcs __read_mostly = {
+    .name = "ARM_HVM",
+};
+
+/* Initcall enabling hvm functionality. */
+static int __init hvm_enable(void)
+{
+    if ( opt_altp2m_enabled )
+        hvm_funcs.altp2m_supported = 1;
+    else
+        hvm_funcs.altp2m_supported = 0;
+
+    return 0;
+}
+presmp_initcall(hvm_enable);
+
 long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
     long rc = 0;
diff --git a/xen/include/asm-arm/hvm/hvm.h b/xen/include/asm-arm/hvm/hvm.h
new file mode 100644
index 0000000..96c455c
--- /dev/null
+++ b/xen/include/asm-arm/hvm/hvm.h
@@ -0,0 +1,47 @@
+/*
+ * include/asm-arm/hvm/hvm.h
+ *
+ * Copyright (c) 2016, Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASM_ARM_HVM_HVM_H__
+#define __ASM_ARM_HVM_HVM_H__
+
+struct hvm_function_table {
+    char *name;
+
+    /* Necessary hardware support for alternate p2m's. */
+    bool_t altp2m_supported;
+};
+
+extern struct hvm_function_table hvm_funcs;
+
+/* Returns true if hardware supports alternate p2m's */
+static inline bool_t hvm_altp2m_supported(void)
+{
+    return hvm_funcs.altp2m_supported;
+}
+
+#endif /* __ASM_ARM_HVM_HVM_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.8.3


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