xen: XEN_DOMCTL_gethvmcontext hypercall

The semantics of XEN_DOMCTL_gethvmcontext are little interesting.

If the 'buffer' field of the structure is NULL, the hypercall is a request for
the required buffer size, which written into the 'size' paramater.

If 'buffer' is non NULL, Xen will write to the buffer, and update 'size' with
the amount of data written.

From: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13732 a5019735-40e9-0310-863c-91ae7b9d1cf9
2 files changed