diff options
Diffstat (limited to 'queue-6.8/x86-bugs-remove-config_bhi_mitigation_auto-and-spectre_bhi-auto.patch')
| -rw-r--r-- | queue-6.8/x86-bugs-remove-config_bhi_mitigation_auto-and-spectre_bhi-auto.patch | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/queue-6.8/x86-bugs-remove-config_bhi_mitigation_auto-and-spectre_bhi-auto.patch b/queue-6.8/x86-bugs-remove-config_bhi_mitigation_auto-and-spectre_bhi-auto.patch new file mode 100644 index 0000000000..637fffd705 --- /dev/null +++ b/queue-6.8/x86-bugs-remove-config_bhi_mitigation_auto-and-spectre_bhi-auto.patch @@ -0,0 +1,102 @@ +From 36d4fe147c870f6d3f6602befd7ef44393a1c87a Mon Sep 17 00:00:00 2001 +From: Josh Poimboeuf <jpoimboe@kernel.org> +Date: Wed, 10 Apr 2024 22:40:50 -0700 +Subject: x86/bugs: Remove CONFIG_BHI_MITIGATION_AUTO and spectre_bhi=auto + +From: Josh Poimboeuf <jpoimboe@kernel.org> + +commit 36d4fe147c870f6d3f6602befd7ef44393a1c87a upstream. + +Unlike most other mitigations' "auto" options, spectre_bhi=auto only +mitigates newer systems, which is confusing and not particularly useful. + +Remove it. + +Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> +Signed-off-by: Ingo Molnar <mingo@kernel.org> +Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> +Cc: Sean Christopherson <seanjc@google.com> +Cc: Linus Torvalds <torvalds@linux-foundation.org> +Link: https://lore.kernel.org/r/412e9dc87971b622bbbaf64740ebc1f140bff343.1712813475.git.jpoimboe@kernel.org +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + Documentation/admin-guide/hw-vuln/spectre.rst | 4 ---- + Documentation/admin-guide/kernel-parameters.txt | 3 --- + arch/x86/Kconfig | 4 ---- + arch/x86/kernel/cpu/bugs.c | 10 +--------- + 4 files changed, 1 insertion(+), 20 deletions(-) + +--- a/Documentation/admin-guide/hw-vuln/spectre.rst ++++ b/Documentation/admin-guide/hw-vuln/spectre.rst +@@ -669,10 +669,6 @@ kernel command line. + needed. + off + Disable the mitigation. +- auto +- Enable the HW mitigation if needed, but +- *don't* enable the SW mitigation except for KVM. +- The system may be vulnerable. + + For spectre_v2_user see Documentation/admin-guide/kernel-parameters.txt + +--- a/Documentation/admin-guide/kernel-parameters.txt ++++ b/Documentation/admin-guide/kernel-parameters.txt +@@ -6040,9 +6040,6 @@ + on - (default) Enable the HW or SW mitigation + as needed. + off - Disable the mitigation. +- auto - Enable the HW mitigation if needed, but +- *don't* enable the SW mitigation except +- for KVM. The system may be vulnerable. + + spectre_v2= [X86] Control mitigation of Spectre variant 2 + (indirect branch speculation) vulnerability. +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -2630,10 +2630,6 @@ config SPECTRE_BHI_OFF + bool "off" + help + Equivalent to setting spectre_bhi=off command line parameter. +-config SPECTRE_BHI_AUTO +- bool "auto" +- help +- Equivalent to setting spectre_bhi=auto command line parameter. + + endchoice + +--- a/arch/x86/kernel/cpu/bugs.c ++++ b/arch/x86/kernel/cpu/bugs.c +@@ -1624,13 +1624,10 @@ static bool __init spec_ctrl_bhi_dis(voi + enum bhi_mitigations { + BHI_MITIGATION_OFF, + BHI_MITIGATION_ON, +- BHI_MITIGATION_AUTO, + }; + + static enum bhi_mitigations bhi_mitigation __ro_after_init = +- IS_ENABLED(CONFIG_SPECTRE_BHI_ON) ? BHI_MITIGATION_ON : +- IS_ENABLED(CONFIG_SPECTRE_BHI_OFF) ? BHI_MITIGATION_OFF : +- BHI_MITIGATION_AUTO; ++ IS_ENABLED(CONFIG_SPECTRE_BHI_ON) ? BHI_MITIGATION_ON : BHI_MITIGATION_OFF; + + static int __init spectre_bhi_parse_cmdline(char *str) + { +@@ -1641,8 +1638,6 @@ static int __init spectre_bhi_parse_cmdl + bhi_mitigation = BHI_MITIGATION_OFF; + else if (!strcmp(str, "on")) + bhi_mitigation = BHI_MITIGATION_ON; +- else if (!strcmp(str, "auto")) +- bhi_mitigation = BHI_MITIGATION_AUTO; + else + pr_err("Ignoring unknown spectre_bhi option (%s)", str); + +@@ -1672,9 +1667,6 @@ static void __init bhi_select_mitigation + setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT); + pr_info("Spectre BHI mitigation: SW BHB clearing on vm exit\n"); + +- if (bhi_mitigation == BHI_MITIGATION_AUTO) +- return; +- + /* Mitigate syscalls when the mitigation is forced =on */ + setup_force_cpu_cap(X86_FEATURE_CLEAR_BHB_LOOP); + pr_info("Spectre BHI mitigation: SW BHB clearing on syscall\n"); |