| Date | Mon, 21 Aug 2023 16:16:19 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 04/22] x86/srso: Fix SBPB enablement for spec_rstack_overflow=off |
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On Sun, Aug 20, 2023 at 06:19:01PM -0700, Josh Poimboeuf wrote: > If the user has requested no SRSO mitigation, other mitigations can use > the lighter-weight SBPB instead of IBPB. > > Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") > Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> > --- > arch/x86/kernel/cpu/bugs.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c > index b0ae985aa6a4..10499bcd4e39 100644 > --- a/arch/x86/kernel/cpu/bugs.c > +++ b/arch/x86/kernel/cpu/bugs.c > @@ -2433,7 +2433,7 @@ static void __init srso_select_mitigation(void) > > switch (srso_cmd) { > case SRSO_CMD_OFF: > - return; > + goto pred_cmd;
Can't do that - you need to synchronize it with retbleed. If retbleed has selected IBPB mitigation you must not override it.
It's a whole different story whether it makes sense.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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