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Re: [Xen-devel] [PATCH v3 08/23] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'. (v2)
- To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
- From: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
- Date: Tue, 16 Feb 2016 11:31:50 +0000
- Cc: Wei Liu <wei.liu2@xxxxxxxxxx>, Ian Campbell <ian.campbell@xxxxxxxxxx>, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>, jinsong.liu@xxxxxxxxxxxxxxx, Ian Jackson <ian.jackson@xxxxxxxxxxxxx>, mpohlack@xxxxxxxxx, Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, andrew.cooper3@xxxxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxxx, Keir Fraser <keir@xxxxxxx>, sasha.levin@xxxxxxxxxx
- Delivery-date: Tue, 16 Feb 2016 11:32:07 +0000
- List-id: Xen developer discussion <xen-devel.lists.xen.org>
On 02/12/2016 06:05 PM, Konrad Rzeszutek Wilk wrote:
This change demonstrates how to generate an xSplice ELF payload.
The idea here is that we want to patch in the hypervisor
the 'xen_version_extra' function with an function that will
return 'Hello World'. The 'xl info | grep extraversion'
will reflect the new value after the patching.
To generate this ELF payload file we need:
- C code of the new code (xen_hello_world_func.c).
- C code generating the .xsplice.funcs structure
(xen_hello_world.c)
- The address of the old code (xen_extra_version). We
retrieve it by using 'nm --defined' on xen-syms.
- The size of the new and old code for which we use
nm --defined -S on our code and xen-syms respectively.
snip
diff --git a/tools/misc/xsplice.lds b/tools/misc/xsplice.lds
new file mode 100644
index 0000000..f52eb8c
--- /dev/null
+++ b/tools/misc/xsplice.lds
@@ -0,0 +1,11 @@
+OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
+OUTPUT_ARCH(i386:x86-64)
+ENTRY(xsplice_hello_world)
+SECTIONS
+{
+ /* The hypervisor expects ".xsplice.func", so change
+ * the ".data.xsplice_hello_world" to it. */
+
+ .xsplice.funcs : { *(*.xsplice_hello_world) }
+
+}
I think this file can be dropped now, nothing uses it as far as I can see.
--
Ross Lagerwall
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