From a4c714fe9746bf5a434bb798b26ebba278b798c1 Mon Sep 17 00:00:00 2001 From: Pawan Gupta Date: Wed, 8 Jul 2026 11:40:14 -0700 Subject: [PATCH] x86/bugs: Don't use cpu-type matching in cpu_vuln_blacklist Thomas Gleixner pointed out that cpu-type is a per-CPU property while hybrid is a system property; conflating the two in the CPU matching infrastructure is wrong. Currently, on a hybrid system x86_match_cpu() matches any cpu-type. This works if the intent is to find the possibility of a cpu-type in a system. But fails if matching for the cpu-type of a given CPU. Borislav posted a cleanup here: https://lore.kernel.org/all/20260703193222.GFakgORjvxwnZTPRnI@fat_crate.local To make way for the cleanup stop matching cpu-type in cpu_vuln_blacklist. RFDS is the only user, so drop the VULNBL_INTEL_TYPE entries and fold their RFDS bit into the base Alder Lake (0x97) and Raptor Lake (0xB7) blacklist entries. For now open-code cpu-type check in vulnerable_to_rfds(). In the future, if more vulnerabilities need cpu-type matching a helper can be added. No functional change intended. Fixes: 722fa0dba74f ("x86/rfds: Exclude P-only parts from the RFDS affected list") Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20260708-cpu-type-vuln-v1-1-85c1d3c704db@linux.intel.com --- arch/x86/kernel/cpu/common.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a3df21d26460..b38126199a5b 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1251,9 +1251,6 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = { #define VULNBL_INTEL_STEPS(vfm, max_stepping, issues) \ X86_MATCH_VFM_STEPS(vfm, X86_STEP_MIN, max_stepping, issues) -#define VULNBL_INTEL_TYPE(vfm, cpu_type, issues) \ - X86_MATCH_VFM_CPU_TYPE(vfm, INTEL_CPU_TYPE_##cpu_type, issues) - #define VULNBL_AMD(family, blacklist) \ VULNBL(AMD, family, X86_MODEL_ANY, blacklist) @@ -1316,11 +1313,9 @@ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = { VULNBL_INTEL_STEPS(INTEL_TIGERLAKE, X86_STEP_MAX, GDS | ITS | ITS_NATIVE_ONLY), VULNBL_INTEL_STEPS(INTEL_LAKEFIELD, X86_STEP_MAX, MMIO | MMIO_SBDS | RETBLEED), VULNBL_INTEL_STEPS(INTEL_ROCKETLAKE, X86_STEP_MAX, MMIO | RETBLEED | GDS | ITS | ITS_NATIVE_ONLY), - VULNBL_INTEL_TYPE(INTEL_ALDERLAKE, ATOM, RFDS | VMSCAPE), - VULNBL_INTEL_STEPS(INTEL_ALDERLAKE, X86_STEP_MAX, VMSCAPE), + VULNBL_INTEL_STEPS(INTEL_ALDERLAKE, X86_STEP_MAX, RFDS | VMSCAPE), VULNBL_INTEL_STEPS(INTEL_ALDERLAKE_L, X86_STEP_MAX, RFDS | VMSCAPE), - VULNBL_INTEL_TYPE(INTEL_RAPTORLAKE, ATOM, RFDS | VMSCAPE), - VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE, X86_STEP_MAX, VMSCAPE), + VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE, X86_STEP_MAX, RFDS | VMSCAPE), VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_P, X86_STEP_MAX, RFDS | VMSCAPE), VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_S, X86_STEP_MAX, RFDS | VMSCAPE), VULNBL_INTEL_STEPS(INTEL_METEORLAKE_L, X86_STEP_MAX, VMSCAPE), @@ -1388,7 +1383,21 @@ static bool __init vulnerable_to_rfds(u64 x86_arch_cap_msr) return true; /* Only consult the blacklist when there is no enumeration: */ - return cpu_matches(cpu_vuln_blacklist, RFDS); + if (!cpu_matches(cpu_vuln_blacklist, RFDS)) + return false; + + /* + * ADL and RPL are affected only if they have Atom CPUs. Hybrids have + * both Core and Atom CPUs. Mark unaffected when Atom CPUs are not + * present. + */ + if ((boot_cpu_data.x86_model == 0x97 || + boot_cpu_data.x86_model == 0xB7) && + boot_cpu_data.topo.intel_type != INTEL_CPU_TYPE_ATOM && + !boot_cpu_has(X86_FEATURE_HYBRID_CPU)) + return false; + + return true; } static bool __init vulnerable_to_its(u64 x86_arch_cap_msr)