The following commit has been merged into the x86/bugs branch of tip:
Commit-ID: 98c7a713db91c5a9a7ffc47cd85e7158e0963cb8
Gitweb: https://git.kernel.org/tip/98c7a713db91c5a9a7ffc47cd85e7158e0963cb8
Author: David Kaplan <david.kaplan@xxxxxxx>
AuthorDate: Wed, 08 Jan 2025 14:24:41 -06:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Fri, 28 Feb 2025 12:34:30 +01:00
x86/bugs: Add X86_BUG_SPECTRE_V2_USER
All CPU vulnerabilities with command line options map to a single X86_BUG bit
except for Spectre V2 where both the spectre_v2 and spectre_v2_user command
line options are related to the same bug.
The spectre_v2 command line options mostly relate to user->kernel and
guest->host mitigations, while the spectre_v2_user command line options relate
to user->user or guest->guest protections.
Define a new X86_BUG bit for spectre_v2_user so each *_select_mitigation()
function in bugs.c is related to a unique X86_BUG bit.
No functional changes.
Signed-off-by: David Kaplan <david.kaplan@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20250108202515.385902-2-david.kaplan@xxxxxxx
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/common.c | 4 +++-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index c8701ab..0bc4203 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -537,4 +537,5 @@
#define X86_BUG_RFDS X86_BUG(1*32 + 2) /* "rfds" CPU is vulnerable to Register File Data Sampling */
#define X86_BUG_BHI X86_BUG(1*32 + 3) /* "bhi" CPU is affected by Branch History Injection */
#define X86_BUG_IBPB_NO_RET X86_BUG(1*32 + 4) /* "ibpb_no_ret" IBPB omits return target predictions */
+#define X86_BUG_SPECTRE_V2_USER X86_BUG(1*32 + 5) /* "spectre_v2_user" CPU is affected by Spectre variant 2 attack between user processes */
#endif /* _ASM_X86_CPUFEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 7cce91b..1e80d76 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1331,8 +1331,10 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
- if (!cpu_matches(cpu_vuln_whitelist, NO_SPECTRE_V2))
+ if (!cpu_matches(cpu_vuln_whitelist, NO_SPECTRE_V2)) {
setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
+ setup_force_cpu_bug(X86_BUG_SPECTRE_V2_USER);
+ }
if (!cpu_matches(cpu_vuln_whitelist, NO_SSB) &&
!(x86_arch_cap_msr & ARCH_CAP_SSB_NO) &&
|