diff options
Diffstat (limited to 'debian/patches/bugfix/x86/retbleed/0024-x86-speculation-Add-spectre_v2-ibrs-option-to-suppor.patch')
| -rw-r--r-- | debian/patches/bugfix/x86/retbleed/0024-x86-speculation-Add-spectre_v2-ibrs-option-to-suppor.patch | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/debian/patches/bugfix/x86/retbleed/0024-x86-speculation-Add-spectre_v2-ibrs-option-to-suppor.patch b/debian/patches/bugfix/x86/retbleed/0024-x86-speculation-Add-spectre_v2-ibrs-option-to-suppor.patch new file mode 100644 index 000000000..cbcc64169 --- /dev/null +++ b/debian/patches/bugfix/x86/retbleed/0024-x86-speculation-Add-spectre_v2-ibrs-option-to-suppor.patch @@ -0,0 +1,208 @@ +From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> +Date: Tue, 14 Jun 2022 23:15:55 +0200 +Subject: x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS +Origin: https://git.kernel.org/linus/7c693f54c873691a4b7da05c7e0f74e67745d144 + +Extend spectre_v2= boot option with Kernel IBRS. + + [jpoimboe: no STIBP with IBRS] + +Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> +Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> +Signed-off-by: Borislav Petkov <bp@suse.de> +Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> +Signed-off-by: Borislav Petkov <bp@suse.de> +--- + .../admin-guide/kernel-parameters.txt | 1 + + arch/x86/include/asm/nospec-branch.h | 1 + + arch/x86/kernel/cpu/bugs.c | 66 +++++++++++++++---- + 3 files changed, 54 insertions(+), 14 deletions(-) + +diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt +index 168e164f09eb..0aeea69e9b7a 100644 +--- a/Documentation/admin-guide/kernel-parameters.txt ++++ b/Documentation/admin-guide/kernel-parameters.txt +@@ -5589,6 +5589,7 @@ + eibrs - enhanced IBRS + eibrs,retpoline - enhanced IBRS + Retpolines + eibrs,lfence - enhanced IBRS + LFENCE ++ ibrs - use IBRS to protect kernel + + Not specifying this option is equivalent to + spectre_v2=auto. +diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h +index b6abf0c6b41d..e14046daa7ba 100644 +--- a/arch/x86/include/asm/nospec-branch.h ++++ b/arch/x86/include/asm/nospec-branch.h +@@ -211,6 +211,7 @@ enum spectre_v2_mitigation { + SPECTRE_V2_EIBRS, + SPECTRE_V2_EIBRS_RETPOLINE, + SPECTRE_V2_EIBRS_LFENCE, ++ SPECTRE_V2_IBRS, + }; + + /* The indirect branch speculation control variants */ +diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c +index 8f7c8dfbdbb4..2d7896493220 100644 +--- a/arch/x86/kernel/cpu/bugs.c ++++ b/arch/x86/kernel/cpu/bugs.c +@@ -972,6 +972,7 @@ enum spectre_v2_mitigation_cmd { + SPECTRE_V2_CMD_EIBRS, + SPECTRE_V2_CMD_EIBRS_RETPOLINE, + SPECTRE_V2_CMD_EIBRS_LFENCE, ++ SPECTRE_V2_CMD_IBRS, + }; + + enum spectre_v2_user_cmd { +@@ -1044,11 +1045,12 @@ spectre_v2_parse_user_cmdline(enum spectre_v2_mitigation_cmd v2_cmd) + return SPECTRE_V2_USER_CMD_AUTO; + } + +-static inline bool spectre_v2_in_eibrs_mode(enum spectre_v2_mitigation mode) ++static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode) + { +- return (mode == SPECTRE_V2_EIBRS || +- mode == SPECTRE_V2_EIBRS_RETPOLINE || +- mode == SPECTRE_V2_EIBRS_LFENCE); ++ return mode == SPECTRE_V2_IBRS || ++ mode == SPECTRE_V2_EIBRS || ++ mode == SPECTRE_V2_EIBRS_RETPOLINE || ++ mode == SPECTRE_V2_EIBRS_LFENCE; + } + + static void __init +@@ -1113,12 +1115,12 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) + } + + /* +- * If no STIBP, enhanced IBRS is enabled or SMT impossible, STIBP is not +- * required. ++ * If no STIBP, IBRS or enhanced IBRS is enabled, or SMT impossible, ++ * STIBP is not required. + */ + if (!boot_cpu_has(X86_FEATURE_STIBP) || + !smt_possible || +- spectre_v2_in_eibrs_mode(spectre_v2_enabled)) ++ spectre_v2_in_ibrs_mode(spectre_v2_enabled)) + return; + + /* +@@ -1150,6 +1152,7 @@ static const char * const spectre_v2_strings[] = { + [SPECTRE_V2_EIBRS] = "Mitigation: Enhanced IBRS", + [SPECTRE_V2_EIBRS_LFENCE] = "Mitigation: Enhanced IBRS + LFENCE", + [SPECTRE_V2_EIBRS_RETPOLINE] = "Mitigation: Enhanced IBRS + Retpolines", ++ [SPECTRE_V2_IBRS] = "Mitigation: IBRS", + }; + + static const struct { +@@ -1167,6 +1170,7 @@ static const struct { + { "eibrs,lfence", SPECTRE_V2_CMD_EIBRS_LFENCE, false }, + { "eibrs,retpoline", SPECTRE_V2_CMD_EIBRS_RETPOLINE, false }, + { "auto", SPECTRE_V2_CMD_AUTO, false }, ++ { "ibrs", SPECTRE_V2_CMD_IBRS, false }, + }; + + static void __init spec_v2_print_cond(const char *reason, bool secure) +@@ -1229,6 +1233,24 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) + return SPECTRE_V2_CMD_AUTO; + } + ++ if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) { ++ pr_err("%s selected but not Intel CPU. Switching to AUTO select\n", ++ mitigation_options[i].option); ++ return SPECTRE_V2_CMD_AUTO; ++ } ++ ++ if (cmd == SPECTRE_V2_CMD_IBRS && !boot_cpu_has(X86_FEATURE_IBRS)) { ++ pr_err("%s selected but CPU doesn't have IBRS. Switching to AUTO select\n", ++ mitigation_options[i].option); ++ return SPECTRE_V2_CMD_AUTO; ++ } ++ ++ if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_has(X86_FEATURE_XENPV)) { ++ pr_err("%s selected but running as XenPV guest. Switching to AUTO select\n", ++ mitigation_options[i].option); ++ return SPECTRE_V2_CMD_AUTO; ++ } ++ + spec_v2_print_cond(mitigation_options[i].option, + mitigation_options[i].secure); + return cmd; +@@ -1268,6 +1290,14 @@ static void __init spectre_v2_select_mitigation(void) + break; + } + ++ if (boot_cpu_has_bug(X86_BUG_RETBLEED) && ++ retbleed_cmd != RETBLEED_CMD_OFF && ++ boot_cpu_has(X86_FEATURE_IBRS) && ++ boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { ++ mode = SPECTRE_V2_IBRS; ++ break; ++ } ++ + mode = spectre_v2_select_retpoline(); + break; + +@@ -1284,6 +1314,10 @@ static void __init spectre_v2_select_mitigation(void) + mode = spectre_v2_select_retpoline(); + break; + ++ case SPECTRE_V2_CMD_IBRS: ++ mode = SPECTRE_V2_IBRS; ++ break; ++ + case SPECTRE_V2_CMD_EIBRS: + mode = SPECTRE_V2_EIBRS; + break; +@@ -1300,7 +1334,7 @@ static void __init spectre_v2_select_mitigation(void) + if (mode == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled()) + pr_err(SPECTRE_V2_EIBRS_EBPF_MSG); + +- if (spectre_v2_in_eibrs_mode(mode)) { ++ if (spectre_v2_in_ibrs_mode(mode)) { + /* Force it so VMEXIT will restore correctly */ + x86_spec_ctrl_base |= SPEC_CTRL_IBRS; + write_spec_ctrl_current(x86_spec_ctrl_base, true); +@@ -1311,6 +1345,10 @@ static void __init spectre_v2_select_mitigation(void) + case SPECTRE_V2_EIBRS: + break; + ++ case SPECTRE_V2_IBRS: ++ setup_force_cpu_cap(X86_FEATURE_KERNEL_IBRS); ++ break; ++ + case SPECTRE_V2_LFENCE: + case SPECTRE_V2_EIBRS_LFENCE: + setup_force_cpu_cap(X86_FEATURE_RETPOLINE_LFENCE); +@@ -1337,17 +1375,17 @@ static void __init spectre_v2_select_mitigation(void) + pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n"); + + /* +- * Retpoline means the kernel is safe because it has no indirect +- * branches. Enhanced IBRS protects firmware too, so, enable restricted +- * speculation around firmware calls only when Enhanced IBRS isn't +- * supported. ++ * Retpoline protects the kernel, but doesn't protect firmware. IBRS ++ * and Enhanced IBRS protect firmware too, so enable IBRS around ++ * firmware calls only when IBRS / Enhanced IBRS aren't otherwise ++ * enabled. + * + * Use "mode" to check Enhanced IBRS instead of boot_cpu_has(), because + * the user might select retpoline on the kernel command line and if + * the CPU supports Enhanced IBRS, kernel might un-intentionally not + * enable IBRS around firmware calls. + */ +- if (boot_cpu_has(X86_FEATURE_IBRS) && !spectre_v2_in_eibrs_mode(mode)) { ++ if (boot_cpu_has(X86_FEATURE_IBRS) && !spectre_v2_in_ibrs_mode(mode)) { + setup_force_cpu_cap(X86_FEATURE_USE_IBRS_FW); + pr_info("Enabling Restricted Speculation for firmware calls\n"); + } +@@ -2089,7 +2127,7 @@ static ssize_t mmio_stale_data_show_state(char *buf) + + static char *stibp_state(void) + { +- if (spectre_v2_in_eibrs_mode(spectre_v2_enabled)) ++ if (spectre_v2_in_ibrs_mode(spectre_v2_enabled)) + return ""; + + switch (spectre_v2_user_stibp) { |