5.10-stable review patch. If anyone has any objections, please let me know.
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From: Borislav Petkov (AMD) bp@alien8.de
commit e9fbc47b818b964ddff5df5b2d5c0f5f32f4a147 upstream.
Skip the srso cmd line parsing which is not needed on Zen1/2 with SMT disabled and with the proper microcode applied (latter should be the case anyway) as those are not affected.
Fixes: 5a15d8348881 ("x86/srso: Tie SBPB bit setting to microcode patch detection") Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Link: https://lore.kernel.org/r/20230813104517.3346-1-bp@alien8.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/cpu/bugs.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2329,8 +2329,10 @@ static void __init srso_select_mitigatio * IBPB microcode has been applied. */ if ((boot_cpu_data.x86 < 0x19) && - (!cpu_smt_possible() || (cpu_smt_control == CPU_SMT_DISABLED))) + (!cpu_smt_possible() || (cpu_smt_control == CPU_SMT_DISABLED))) { setup_force_cpu_cap(X86_FEATURE_SRSO_NO); + return; + } }
if (retbleed_mitigation == RETBLEED_MITIGATION_IBPB) { @@ -2616,6 +2618,9 @@ static ssize_t gds_show_state(char *buf)
static ssize_t srso_show_state(char *buf) { + if (boot_cpu_has(X86_FEATURE_SRSO_NO)) + return sysfs_emit(buf, "Not affected\n"); + return sysfs_emit(buf, "%s%s\n", srso_strings[srso_mitigation], (cpu_has_ibpb_brtype_microcode() ? "" : ", no microcode"));