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Commit 0fd086ed authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Greg Kroah-Hartman
Browse files

x86/speculation: Fix SPEC_CTRL write on SMT state change 



commit 56aa4d221f1ee2c3a49b45b800778ec6e0ab73c5 upstream.

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

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarThadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 18d5a93f

arch/x86/kernel/cpu/bugs.c

+2 −1
Original line number Diff line number Diff line
@@ -1335,7 +1335,8 @@ 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. */