• Tom Lendacky's avatar
    x86/boot: Fix SEV boot failure from change to __PHYSICAL_MASK_SHIFT · 07344b15
    Tom Lendacky authored
    In arch/x86/boot/compressed/kaslr_64.c, CONFIG_AMD_MEM_ENCRYPT support was
    initially #undef'd to support SME with minimal effort.  When support for
    SEV was added, the #undef remained and some minimal support for setting the
    encryption bit was added for building identity mapped pagetable entries.
    
    Commit b83ce5ee ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52")
    changed __PHYSICAL_MASK_SHIFT from 46 to 52 in support of 5-level paging.
    This change resulted in SEV guests failing to boot because the encryption
    bit was no longer being automatically masked out.  The compressed boot
    path now requires sme_me_mask to be defined in order for the pagetable
    functions, such as pud_present(), to properly mask out the encryption bit
    (currently bit 47) when evaluating pagetable entries.
    
    Add an sme_me_mask variable in arch/x86/boot/compressed/mem_encrypt.S,
    which is set when SEV is active, delete the #undef CONFIG_AMD_MEM_ENCRYPT
    from arch/x86/boot/compressed/kaslr_64.c and use sme_me_mask when building
    the identify mapped pagetable entries.
    
    Fixes: b83ce5ee
    
     ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52")
    Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brijesh Singh <brijesh.singh@amd.com>
    Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Link: https://lkml.kernel.org/r/20180327220711.8702.55842.stgit@tlendack-t1.amdoffice.net
    07344b15