This is a note to let you know that I've just added the patch titled x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed Oct 5 12:28:43 PM CEST 2022 From: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx> Date: Mon, 3 Oct 2022 10:10:16 -0300 Subject: x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() To: stable@xxxxxxxxxxxxxxx Cc: x86@xxxxxxxxxx, kvm@xxxxxxxxxxxxxxx, bp@xxxxxxxxx, pbonzini@xxxxxxxxxx, peterz@xxxxxxxxxxxxx, jpoimboe@xxxxxxxxxx Message-ID: <20221003131038.12645-16-cascardo@xxxxxxxxxxxxx> From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> commit 166115c08a9b0b846b783088808a27d739be6e8d upstream. retbleed will depend on spectre_v2, while spectre_v2_user depends on retbleed. Break this cycle. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/bugs.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -36,8 +36,9 @@ #include "cpu.h" static void __init spectre_v1_select_mitigation(void); -static void __init retbleed_select_mitigation(void); static void __init spectre_v2_select_mitigation(void); +static void __init retbleed_select_mitigation(void); +static void __init spectre_v2_user_select_mitigation(void); static void __init ssb_select_mitigation(void); static void __init l1tf_select_mitigation(void); static void __init mds_select_mitigation(void); @@ -136,13 +137,19 @@ void __init check_bugs(void) /* Select the proper CPU mitigations before patching alternatives: */ spectre_v1_select_mitigation(); + spectre_v2_select_mitigation(); + /* + * retbleed_select_mitigation() relies on the state set by + * spectre_v2_select_mitigation(); specifically it wants to know about + * spectre_v2=ibrs. + */ retbleed_select_mitigation(); /* - * spectre_v2_select_mitigation() relies on the state set by + * spectre_v2_user_select_mitigation() relies on the state set by * retbleed_select_mitigation(); specifically the STIBP selection is * forced for UNRET. */ - spectre_v2_select_mitigation(); + spectre_v2_user_select_mitigation(); ssb_select_mitigation(); l1tf_select_mitigation(); md_clear_select_mitigation(); @@ -918,13 +925,15 @@ static void __init spec_v2_user_print_co pr_info("spectre_v2_user=%s forced on command line.\n", reason); } +static __ro_after_init enum spectre_v2_mitigation_cmd spectre_v2_cmd; + static enum spectre_v2_user_cmd __init -spectre_v2_parse_user_cmdline(enum spectre_v2_mitigation_cmd v2_cmd) +spectre_v2_parse_user_cmdline(void) { char arg[20]; int ret, i; - switch (v2_cmd) { + switch (spectre_v2_cmd) { case SPECTRE_V2_CMD_NONE: return SPECTRE_V2_USER_CMD_NONE; case SPECTRE_V2_CMD_FORCE: @@ -959,7 +968,7 @@ static inline bool spectre_v2_in_ibrs_mo } static void __init -spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) +spectre_v2_user_select_mitigation(void) { enum spectre_v2_user_mitigation mode = SPECTRE_V2_USER_NONE; bool smt_possible = IS_ENABLED(CONFIG_SMP); @@ -972,7 +981,7 @@ spectre_v2_user_select_mitigation(enum s cpu_smt_control == CPU_SMT_NOT_SUPPORTED) smt_possible = false; - cmd = spectre_v2_parse_user_cmdline(v2_cmd); + cmd = spectre_v2_parse_user_cmdline(); switch (cmd) { case SPECTRE_V2_USER_CMD_NONE: goto set_mode; @@ -1289,7 +1298,7 @@ static void __init spectre_v2_select_mit } /* Set up IBPB and STIBP depending on the general spectre V2 command */ - spectre_v2_user_select_mitigation(cmd); + spectre_v2_cmd = cmd; } static void update_stibp_msr(void * __unused) Patches currently in stable-queue which might be from cascardo@xxxxxxxxxxxxx are queue-5.4/x86-speculation-disable-rrsba-behavior.patch queue-5.4/kvm-vmx-flatten-__vmx_vcpu_run.patch queue-5.4/x86-kvm-vmx-make-noinstr-clean.patch queue-5.4/revert-x86-speculation-add-rsb-vm-exit-protections.patch queue-5.4/kvm-vmx-fix-ibrs-handling-after-vmexit.patch queue-5.4/kvm-vmx-prevent-guest-rsb-poisoning-attacks-with-eibrs.patch queue-5.4/kvm-nvmx-use-__vmx_vcpu_run-in-nested_vmx_check_vmentry_hw.patch queue-5.4/x86-bugs-keep-a-per-cpu-ia32_spec_ctrl-value.patch queue-5.4/x86-cpu-amd-enumerate-btc_no.patch queue-5.4/x86-speculation-fix-firmware-entry-spec_ctrl-handling.patch queue-5.4/x86-speculation-add-spectre_v2-ibrs-option-to-support-kernel-ibrs.patch queue-5.4/x86-cpu-add-consistent-cpu-match-macros.patch queue-5.4/x86-speculation-remove-x86_spec_ctrl_mask.patch queue-5.4/x86-bugs-add-cannon-lake-to-retbleed-affected-cpu-list.patch queue-5.4/x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch queue-5.4/x86-speculation-fill-rsb-on-vmexit-for-ibrs.patch queue-5.4/x86-cpu-add-a-steppings-field-to-struct-x86_cpu_id.patch queue-5.4/kvm-vmx-convert-launched-argument-to-flags.patch queue-5.4/x86-common-stamp-out-the-stepping-madness.patch queue-5.4/x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch queue-5.4/x86-bugs-report-intel-retbleed-vulnerability.patch queue-5.4/x86-speculation-change-fill_return_buffer-to-work-with-objtool.patch queue-5.4/x86-cpufeatures-move-retpoline-flags-to-word-11.patch queue-5.4/x86-speculation-fix-spec_ctrl-write-on-smt-state-change.patch queue-5.4/kvm-vmx-use-test-reg-reg-instead-of-cmp-0-reg-in-vmenter.s.patch queue-5.4/x86-bugs-optimize-spec_ctrl-msr-writes.patch queue-5.4/x86-bugs-report-amd-retbleed-vulnerability.patch queue-5.4/x86-speculation-fix-rsb-filling-with-config_retpoline-n.patch queue-5.4/intel_idle-disable-ibrs-during-long-idle.patch queue-5.4/x86-speculation-use-declare_per_cpu-for-x86_spec_ctrl_current.patch queue-5.4/x86-entry-remove-skip_r11rcx.patch queue-5.4/x86-speculation-use-cached-host-spec_ctrl-value-for-guest-entry-exit.patch queue-5.4/x86-devicetable-move-x86-specific-macro-out-of-generic-code.patch queue-5.4/x86-bugs-add-amd-retbleed-boot-parameter.patch queue-5.4/x86-entry-add-kernel-ibrs-implementation.patch queue-5.4/revert-x86-cpu-add-a-steppings-field-to-struct-x86_cpu_id.patch queue-5.4/x86-speculation-add-rsb-vm-exit-protections.patch