c0fecaa44d
As it turns out, Xen does not guarantee that EFI boot services data regions in memory are preserved, which means that EFI configuration tables pointing into such memory regions may be corrupted before the dom0 OS has had a chance to inspect them. This is causing problems for Qubes OS when it attempts to perform system firmware updates, which requires that the contents of the EFI System Resource Table are valid when the fwupd userspace program runs. However, other configuration tables such as the memory attributes table or the runtime properties table are equally affected, and so we need a comprehensive workaround that works for any table type. So when running under Xen, check the EFI memory descriptor covering the start of the table, and disregard the table if it does not reside in memory that is preserved by Xen. Co-developed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com> Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.