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    Subject[PATCH v3 10/12] x86/vsyscall: Document the fact that vsyscall=emulate disables LASS
    Date
    Since EMULATE mode of vsyscall disables LASS, because fixing the LASS
    violations during the EMULATE mode would need complex instruction
    decoding, document this fact in kernel-parameters.txt.

    Cc: Andy Lutomirski <luto@kernel.org>
    Suggested-by: Dave Hansen <dave.hansen@intel.com>
    Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    ---
    Documentation/admin-guide/kernel-parameters.txt | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
    index 9e5bab29685f..efed9193107e 100644
    --- a/Documentation/admin-guide/kernel-parameters.txt
    +++ b/Documentation/admin-guide/kernel-parameters.txt
    @@ -6850,7 +6850,9 @@

    emulate Vsyscalls turn into traps and are emulated
    reasonably safely. The vsyscall page is
    - readable.
    + readable. This also disables the LASS
    + feature to allow userspace to poke around
    + the vsyscall page.

    xonly [default] Vsyscalls turn into traps and are
    emulated reasonably safely. The vsyscall
    --
    2.39.2
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