5.15-stable review patch. If anyone has any objections, please let me know.
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From: Sean Christopherson seanjc@google.com
commit f337a6a21e2fd67eadea471e93d05dd37baaa9be upstream.
Initialize cpu_mitigations to CPU_MITIGATIONS_OFF if the kernel is built with CONFIG_SPECULATION_MITIGATIONS=n, as the help text quite clearly states that disabling SPECULATION_MITIGATIONS is supposed to turn off all mitigations by default.
│ If you say N, all mitigations will be disabled. You really │ should know what you are doing to say so.
As is, the kernel still defaults to CPU_MITIGATIONS_AUTO, which results in some mitigations being enabled in spite of SPECULATION_MITIGATIONS=n.
Fixes: f43b9876e857 ("x86/retbleed: Add fine grained Kconfig knobs") Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Ingo Molnar mingo@kernel.org Reviewed-by: Daniel Sneddon daniel.sneddon@linux.intel.com Cc: stable@vger.kernel.org Cc: Linus Torvalds torvalds@linux-foundation.org Link: https://lore.kernel.org/r/20240409175108.1512861-2-seanjc@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/cpu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -2722,7 +2722,8 @@ enum cpu_mitigations { };
static enum cpu_mitigations cpu_mitigations __ro_after_init = - CPU_MITIGATIONS_AUTO; + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : + CPU_MITIGATIONS_OFF;
static int __init mitigations_parse_cmdline(char *arg) {