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x86/bugs: Don't use cpu-type matching in cpu_vuln_blacklist

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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: 722fa0dba7 ("x86/rfds: Exclude P-only parts from the RFDS affected list")
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260708-cpu-type-vuln-v1-1-85c1d3c704db@linux.intel.com
This commit is contained in:
Pawan Gupta 2026-07-08 11:40:14 -07:00 committed by Borislav Petkov (AMD)
parent 3eaa50e1e2
commit a4c714fe97
1 changed files with 17 additions and 8 deletions
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25
arch/x86/kernel/cpu/common.c
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@ -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)