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authorJosh Poimboeuf <jpoimboe@kernel.org>2022-06-14 23:16:07 +0200
committerBorislav Petkov <bp@suse.de>2022-06-27 10:34:00 +0200
commit56aa4d221f1ee2c3a49b45b800778ec6e0ab73c5 (patch)
treea6e1ada3a4703390ea0f2c874fc0e8552acf050c /arch
parente6aa13622ea8283cc699cac5d018cc40a2ba2010 (diff)
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x86/speculation: Fix SPEC_CTRL write on SMT state change
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/bugs.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 108bd74289c5..9b80059c4e02 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1458,7 +1458,8 @@ static void __init spectre_v2_select_mitigation(void)
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. */