@@ -248,6 +248,7 @@ xen/arch/x86/efi/mkreloc
xen/arch/x86/test/config.h
xen/arch/x86/test/xen_hello_world.xsplice
xen/arch/x86/test/xen_bye_world.xsplice
+xen/arch/x86/test/xen_replace_world.xsplice
xen/arch/*/efi/boot.c
xen/arch/*/efi/compat.c
xen/arch/*/efi/efi.h
@@ -8,15 +8,18 @@ ifdef CONFIG_XSPLICE
XSPLICE := xen_hello_world.xsplice
XSPLICE_BYE := xen_bye_world.xsplice
+XSPLICE_REPLACE := xen_replace_world.xsplice
default: xsplice
install: xsplice
$(INSTALL_DATA) $(XSPLICE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
$(INSTALL_DATA) $(XSPLICE_BYE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_BYE)
+ $(INSTALL_DATA) $(XSPLICE_REPLACE) $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_REPLACE)
uninstall:
rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE)
rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_BYE)
+ rm -f $(DESTDIR)$(DEBUG_DIR)/$(XSPLICE_REPLACE)
else
@@ -80,3 +83,8 @@ xsplice: config.h build_id.o
$(MAKE) -f $(BASEDIR)/Rules.mk hello_world_build_id.o
$(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE_BYE) \
xen_bye_world_func.o xen_bye_world.o hello_world_build_id.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_replace_world_func.o
+ $(MAKE) -f $(BASEDIR)/Rules.mk xen_replace_world.o
+ $(LD) $(LDFLAGS) $(build_id_linker) -r -o $(XSPLICE_REPLACE) \
+ xen_replace_world_func.o \
+ xen_replace_world.o build_id.o
new file mode 100644
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include <xen/config.h>
+#include <xen/types.h>
+#include <xen/xsplice_patch.h>
+#include <xen/xsplice.h>
+#include "config.h"
+#include <xen/lib.h>
+
+static char xen_replace_world_name[] = "xen_replace_world";
+extern const char *xen_replace_world(void);
+
+/* External symbol. */
+extern const char *xen_extra_version(void);
+
+struct xsplice_patch_func __section(".xsplice.funcs") xsplice_xen_replace_world = {
+ .name = xen_replace_world_name,
+ .new_addr = (unsigned long)(xen_replace_world),
+ .old_addr = (unsigned long)(xen_extra_version),
+ .new_size = NEW_CODE_SZ,
+ .old_size = OLD_CODE_SZ,
+};
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
new file mode 100644
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
+ *
+ */
+
+#include <xen/config.h>
+#include <xen/types.h>
+#include <asm/nops.h>
+#include <asm/alternative.h>
+
+/* Our replacement function for xen_hello_world. */
+const char *xen_replace_world(void)
+{
+ return "Hello Again World!";
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
With this third payload one can do: -bash-4.1# xen-xsplice load xen_hello_world.xsplice Uploading xen_hello_world.xsplice (10148 bytes) Performing check: completed Performing apply:. completed [xen_hello_world depends on hypervisor build-id] -bash-4.1# xen-xsplice load xen_bye_world.xsplice Uploading xen_bye_world.xsplice (7076 bytes) Performing check: completed Performing apply:. completed [xen_bye_world depends on xen_hello_world build-id] -bash-4.1# xen-xsplice upload xen_replace_world xen_replace_world.xsplice Uploading xen_replace_world.xsplice (7148 bytes) -bash-4.1# xen-xsplice list ID | status ----------------------------------------+------------ xen_hello_world | APPLIED xen_bye_world | APPLIED xen_replace_world | CHECKED -bash-4.1# xen-xsplice replace xen_replace_world Performing replace:. completed -bash-4.1# xl info | grep extra xen_extra : Hello Again World! -bash-4.1# xen-xsplice list ID | status ----------------------------------------+------------ xen_hello_world | CHECKED xen_bye_world | CHECKED xen_replace_world | APPLIED and revert both of the previous payloads and apply the xen_replace_world. All the magic of this is in the Makefile - we extract the build-id from the hypervisor (xen-syms) and jam it in the xen_replace_world as .xsplice.depends. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- Cc: Keir Fraser <keir@xen.org> Cc: Jan Beulich <jbeulich@suse.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> v4: New. Make the objcopy use -S to strip the name. --- --- .gitignore | 1 + xen/arch/x86/test/Makefile | 8 +++++++ xen/arch/x86/test/xen_replace_world.c | 35 ++++++++++++++++++++++++++++++ xen/arch/x86/test/xen_replace_world_func.c | 25 +++++++++++++++++++++ 4 files changed, 69 insertions(+) create mode 100644 xen/arch/x86/test/xen_replace_world.c create mode 100644 xen/arch/x86/test/xen_replace_world_func.c