f8f6ae5d07
The purpose of io_remap_pfn_range() is to map IO memory, such as a
memory mapped IO exposed through a PCI BAR. IO devices do not
understand encryption, so this memory must always be decrypted.
Automatically call pgprot_decrypted() as part of the generic
implementation.
This fixes a bug where enabling AMD SME causes subsystems, such as RDMA,
using io_remap_pfn_range() to expose BAR pages to user space to fail.
The CPU will encrypt access to those BAR pages instead of passing
unencrypted IO directly to the device.
Places not mapping IO should use remap_pfn_range().
Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Dave Young" <dyoung@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/0-v1-025d64bdf6c4+e-amd_sme_fix_jgg@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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.