[tip: x86/cpu] x86/rfds: Exclude P-only parts from the RFDS affected list
From: tip-bot2 for Pawan Gupta
Date: Wed Mar 12 2025 - 05:56:00 EST
The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: 8c7768105a84c16b9d71af2fa2d2c50ff3c80f4e
Gitweb: https://git.kernel.org/tip/8c7768105a84c16b9d71af2fa2d2c50ff3c80f4e
Author: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
AuthorDate: Tue, 11 Mar 2025 08:03:08 -07:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Tue, 11 Mar 2025 20:53:30 +01:00
x86/rfds: Exclude P-only parts from the RFDS affected list
The affected CPU table (cpu_vuln_blacklist) marks Alderlake and Raptorlake
P-only parts affected by RFDS. This is not true because only E-cores are
affected by RFDS. With the current family/model matching it is not possible
to differentiate the unaffected parts, as the affected and unaffected
hybrid variants have the same model number.
Add a cpu-type match as well for such parts so as to exclude P-only parts
being marked as affected.
Note, family/model and cpu-type enumeration could be inaccurate in
virtualized environments. In a guest affected status is decided by RFDS_NO
and RFDS_CLEAR bits exposed by VMMs.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-5-e8514dcaaff2@xxxxxxxxxxxxxxx
---
Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst | 8 +-------
arch/x86/kernel/cpu/common.c | 7 ++++--
2 files changed, 5 insertions(+), 10 deletions(-)
diff --git a/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst b/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
index 0585d02..ad15417 100644
--- a/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
+++ b/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
@@ -29,14 +29,6 @@ Below is the list of affected Intel processors [#f1]_:
RAPTORLAKE_S 06_BFH
=================== ============
-As an exception to this table, Intel Xeon E family parts ALDERLAKE(06_97H) and
-RAPTORLAKE(06_B7H) codenamed Catlow are not affected. They are reported as
-vulnerable in Linux because they share the same family/model with an affected
-part. Unlike their affected counterparts, they do not enumerate RFDS_CLEAR or
-CPUID.HYBRID. This information could be used to distinguish between the
-affected and unaffected parts, but it is deemed not worth adding complexity as
-the reporting is fixed automatically when these parts enumerate RFDS_NO.
-
Mitigation
==========
Intel released a microcode update that enables software to clear sensitive
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 5f81c55..92fe56c 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1203,6 +1203,9 @@ 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)
@@ -1251,9 +1254,9 @@ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
VULNBL_INTEL_STEPS(INTEL_TIGERLAKE, X86_STEP_MAX, GDS),
VULNBL_INTEL_STEPS(INTEL_LAKEFIELD, X86_STEP_MAX, MMIO | MMIO_SBDS | RETBLEED),
VULNBL_INTEL_STEPS(INTEL_ROCKETLAKE, X86_STEP_MAX, MMIO | RETBLEED | GDS),
- VULNBL_INTEL_STEPS(INTEL_ALDERLAKE, X86_STEP_MAX, RFDS),
+ VULNBL_INTEL_TYPE(INTEL_ALDERLAKE, ATOM, RFDS),
VULNBL_INTEL_STEPS(INTEL_ALDERLAKE_L, X86_STEP_MAX, RFDS),
- VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE, X86_STEP_MAX, RFDS),
+ VULNBL_INTEL_TYPE(INTEL_RAPTORLAKE, ATOM, RFDS),
VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_P, X86_STEP_MAX, RFDS),
VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_S, X86_STEP_MAX, RFDS),
VULNBL_INTEL_STEPS(INTEL_ATOM_GRACEMONT, X86_STEP_MAX, RFDS),