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: 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: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Josh Poimboeuf 2022-11-17 18:19:40 +09:00 committed by Greg Kroah-Hartman
parent 93f9510620
commit 8bafec7f0e

View File

@ -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. */