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authorBreno Leitao <leitao@debian.org>2024-07-29 09:40:51 -0700
committerBorislav Petkov (AMD) <bp@alien8.de>2024-07-30 10:56:20 +0200
commit163f9fe6b625c5f5c4d5b05265b194388182454b (patch)
treecad01e6bd608de5efa491c567a93f58034f516ab
parentx86/bugs: Add a separate config for TAA (diff)
downloadwireguard-linux-163f9fe6b625c5f5c4d5b05265b194388182454b.tar.xz
wireguard-linux-163f9fe6b625c5f5c4d5b05265b194388182454b.zip
x86/bugs: Add a separate config for MMIO Stable Data
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 MMIO Stale data 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/20240729164105.554296-4-leitao@debian.org
-rw-r--r--arch/x86/Kconfig12
-rw-r--r--arch/x86/kernel/cpu/bugs.c3
2 files changed, 14 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 712a4f8cb7dd..b169677ec4ac 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2670,6 +2670,18 @@ config MITIGATION_TAA
which is available in various CPU internal buffers by using
asynchronous aborts within an Intel TSX transactional region.
See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
+
+config MITIGATION_MMIO_STALE_DATA
+ bool "Mitigate MMIO Stale Data hardware bug"
+ depends on CPU_SUP_INTEL
+ default y
+ help
+ Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO
+ Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
+ vulnerabilities that can expose data. The vulnerabilities require the
+ attacker to have access to MMIO.
+ See also
+ <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
endif
config ARCH_HAS_ADD_PAGES
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index ab306986762d..9b0d058f3fe8 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -393,7 +393,8 @@ enum mmio_mitigations {
};
/* Default mitigation for Processor MMIO Stale Data vulnerabilities */
-static enum mmio_mitigations mmio_mitigation __ro_after_init = MMIO_MITIGATION_VERW;
+static enum mmio_mitigations mmio_mitigation __ro_after_init =
+ IS_ENABLED(CONFIG_MITIGATION_MMIO_STALE_DATA) ? MMIO_MITIGATION_VERW : MMIO_MITIGATION_OFF;
static bool mmio_nosmt __ro_after_init = false;
static const char * const mmio_strings[] = {