Commit 3a4ee4ff authored by Breno Leitao's avatar Breno Leitao Committed by Borislav Petkov (AMD)
Browse files

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: default avatarBreno Leitao <leitao@debian.org>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20240729164105.554296-5-leitao@debian.org
parent 163f9fe6

arch/x86/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/cpu/bugs.c

+2 −1
Original line number Diff line number Diff line
@@ -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