Pre-4.17 kernels ignored start_info's rsdp_paddr pointer and instead
relied on finding RSDP in standard location in BIOS RO memory. This
has worked since that's where Xen used to place it.
However, with recent Xen change (commit 4a5733771e6f ("libxl: put RSDP
for PVH guest near 4GB")) it prefers to keep RSDP at a "non-standard"
address. Even though as of commit b17d9d1df3 ("x86/xen: Add pvh
specific rsdp address retrieval function") Linux is able to find RSDP,
for back-compatibility reasons we need to indicate to Xen that we can
handle this, an we do so by setting XENFEAT_linux_rsdp_unrestricted
flag in ELF notes.
(Also take this opportunity and sync features.h header file with Xen)
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Linux kernel
============
This file was moved to Documentation/admin-guide/README.rst
Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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