lkml.org 
[lkml]   [2022]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.15 61/78] x86/speculation: Fix SPEC_CTRL write on SMT state change
    Date
    From: Josh Poimboeuf <jpoimboe@kernel.org>

    commit 56aa4d221f1ee2c3a49b45b800778ec6e0ab73c5 upstream.

    If the SMT state changes, SSBD might get accidentally disabled. Fix
    that.

    Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Signed-off-by: Borislav Petkov <bp@suse.de>
    Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    arch/x86/kernel/cpu/bugs.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    --- a/arch/x86/kernel/cpu/bugs.c
    +++ b/arch/x86/kernel/cpu/bugs.c
    @@ -1451,7 +1451,8 @@ static void __init spectre_v2_select_mit

    static void update_stibp_msr(void * __unused)
    {
    - write_spec_ctrl_current(x86_spec_ctrl_base, true);
    + u64 val = spec_ctrl_current() | (x86_spec_ctrl_base & SPEC_CTRL_STIBP);
    + write_spec_ctrl_current(val, true);
    }

    /* Update x86_spec_ctrl_base in case SMT state changed. */

    \
     
     \ /
      Last update: 2022-07-12 21:05    [W:4.193 / U:0.056 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site