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authorBreno Leitao <leitao@debian.org>2024-07-29 19:40:52 +0300
committerBorislav Petkov (AMD) <bp@alien8.de>2024-07-30 12:23:17 +0300
commit3a4ee4ff819b2bd09f1eca4a90846f2be449bd51 (patch)
tree718c385338399380e9e1911253b4bd9ea2524100 /arch/x86
parent163f9fe6b625c5f5c4d5b05265b194388182454b (diff)
downloadlinux-3a4ee4ff819b2bd09f1eca4a90846f2be449bd51.tar.xz
x86/bugs: Add a separate config for L1TF
Currently, the CONFIG_SPECULATION_MITIGATIONS is halfway populated, where some mitigations have entries in Kconfig, and they could be modified, while others mitigations do not have Kconfig entries, and could not be controlled at build time. Create an entry for the L1TF CPU mitigation under CONFIG_SPECULATION_MITIGATIONS. This allow users to enable or disable it at compilation time. Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20240729164105.554296-5-leitao@debian.org
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/Kconfig10
-rw-r--r--arch/x86/kernel/cpu/bugs.c3
2 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b169677ec4ac..290f0865fd85 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2682,6 +2682,16 @@ config MITIGATION_MMIO_STALE_DATA
attacker to have access to MMIO.
See also
<file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
+
+config MITIGATION_L1TF
+ bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
+ depends on CPU_SUP_INTEL
+ default y
+ help
+ Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
+ hardware vulnerability which allows unprivileged speculative access to data
+ available in the Level 1 Data Cache.
+ See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
endif
config ARCH_HAS_ADD_PAGES
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 9b0d058f3fe8..4fde9bd368ad 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2374,7 +2374,8 @@ EXPORT_SYMBOL_GPL(itlb_multihit_kvm_mitigation);
#define pr_fmt(fmt) "L1TF: " fmt
/* Default mitigation for L1TF-affected CPUs */
-enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_FLUSH;
+enum l1tf_mitigations l1tf_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_L1TF) ? L1TF_MITIGATION_FLUSH : L1TF_MITIGATION_OFF;
#if IS_ENABLED(CONFIG_KVM_INTEL)
EXPORT_SYMBOL_GPL(l1tf_mitigation);
#endif