• Tom Lendacky's avatar
    x86/mm: Add support to access boot related data in the clear · 8f716c9b
    Tom Lendacky authored
    Boot data (such as EFI related data) is not encrypted when the system is
    booted because UEFI/BIOS does not run with SME active. In order to access
    this data properly it needs to be mapped decrypted.
    
    Update early_memremap() to provide an arch specific routine to modify the
    pagetable protection attributes before they are applied to the new
    mapping. This is used to remove the encryption mask for boot related data.
    
    Update memremap() to provide an arch specific routine to determine if RAM
    remapping is allowed.  RAM remapping will cause an encrypted mapping to be
    generated. By preventing RAM remapping, ioremap_cache() will be used
    instead, which will provide a decrypted mapping of the boot related data.
    Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
    Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Reviewed-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>
    Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
    Cc: Alexander Potapenko <glider@google.com>
    Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brijesh Singh <brijesh.singh@amd.com>
    Cc: Dave Young <dyoung@redhat.com>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Jonathan Corbet <corbet@lwn.net>
    Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Cc: Larry Woodman <lwoodman@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Michael S. Tsirkin <mst@redhat.com>
    Cc: Paolo Bonzini <pbonzini@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Radim Krčmář <rkrcmar@redhat.com>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Toshimitsu Kani <toshi.kani@hpe.com>
    Cc: kasan-dev@googlegroups.com
    Cc: kvm@vger.kernel.org
    Cc: linux-arch@vger.kernel.org
    Cc: linux-doc@vger.kernel.org
    Cc: linux-efi@vger.kernel.org
    Cc: linux-mm@kvack.org
    Link: http://lkml.kernel.org/r/81fb6b4117a5df6b9f2eda342f81bbef4b23d2e5.1500319216.git.thomas.lendacky@amd.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    8f716c9b
io.h 5.76 KB