[PATCH v7 0/4] Utilize cpu-type for CPU matching

[PATCH v7 0/4] Utilize cpu-type for CPU matching

[Pawan Gupta]

v7:
- Moved the CPU table cleanup patch out of the series, it does not relate
  to cpu-type detection. Will send it separately.

v6:
- Use the recently added macro VULNBL_INTEL_STEPS() in the affected CPU
  list cleanup patch.
- Rebased to tip/x86/cpu.

This series is now the remaining last 5 patches from the original
series. Below are previously merged patches:

- upstream:
  45239ba39a52 ("x86/cpu: Add CPU type to struct cpuinfo_topology")

- tip:
  x86/cpu: Prepend 0x to the hex values in cpu_debug_show()
  cpufreq: intel_pstate: Avoid SMP calls to get cpu-type
  perf/x86/intel: Use cache cpu-type for hybrid PMU selection
  x86/cpu: Remove get_this_hybrid_cpu_*()

v5: https://lore.kernel.org/r/20241211-add-cpu-type-v5-0-2ae010f50370@linux.intel.com
- Replace usages of get_this_hybrid_cpu_native_id() with its cached value
  in CPU topology structure.
- s/x86_match_cpu_type/x86_match_vendor_cpu_type and add vendor checks
  in the function.
- Some cleanups in intel_pstate.c.
- Collected tags.
- Rebased to v6.13-rc1.

v4: https://lore.kernel.org/r/20240930-add-cpu-type-v4-0-104892b7ab5f@linux.intel.com
- Series doesn't apply to upstream cleanly anymore, rebased to v6.12-rc1,
  resolved the merge conflict in files:
	arch/x86/include/asm/cpu_device_id.h
	arch/x86/kernel/cpu/common.c
- Remove redundant "hw_" in intel_hw_native_model_id().

v3: https://lore.kernel.org/r/20240815-add-cpu-type-v3-0-234162352057@linux.intel.com
- Add a patch to prepend "0x" to hex values in cpu_debug_show() (Borislav).
- Add support to to also get Intel Native Model ID (Dapeng).
- Keep similar models together in the affected processor list (Josh).
- Add a comparison of .init.data in commit message for cpu_vuln_blacklist
  before and after decluttering patch for affected processor list (Josh).
- Drop the debugfs file reference in the commit message (Borislav).
- s/cpu_type/hw_cpu_type/ (Borislav).
- Add a union for hw_cpu_type for easy retrieval of intel_core_type and
  intel_native_model_id.
- Updated commit messages, collected tags.
- Rebased to v6.11-rc3.

Note, I will be off work till Tuesday, will reply to any comments then.

v2: https://lore.kernel.org/r/20240627-add-cpu-type-v2-0-f927bde83ad0@linux.intel.com
- Move CPU-type to the end of the CPU topology structure (Andrew).
- Use c->cpuid_level instead of cpuid_eax(0) (Andrew).
- Move CPU-type enum out of ifdef CONFIG_NUMA (kernel test robot).
- Rename cpu_type to hw_cpu_type (Borislav).
- Explain replacing get_this_hybrid_cpu_type() with topology_hw_cpu_type()
  in the commit message (Dave).
- Fix the alignment in cpu_vuln_whitelist (Andrew).
- Add the obj compare note in the commit message (Dave/Tony).
- s/X86_CPU_TYPE_INTEL_ATOM/ATOM/ in cpu_vuln_whitelist (Dave).

v1: https://lore.kernel.org/r/20240617-add-cpu-type-v1-0-b88998c01e76@linux.intel.com

Hi,

This series adds support for CPU-type (CPUID.1A.EAX[31-24] on Intel) to
differentiate between hybrid variants P+E, P-only, E-only that share the
same Family/Model/Stepping. One of the use case for CPU-type is the
affected CPU table for CPU vulnerabilities, which can now use the CPU-type
to filter the unaffected variants.

* Patch 1 fixes a minor formatting issue in cpu_debug_show().

* Patch 2 adds hardware cpu-type to CPU topology structure and introduces
  topology_hw_cpu_type().

* Patch 3-5 replaces usages of get_this_hybrid_cpu_type() with
  topology_hw_cpu_type().

* Patch 6-8 Updates CPU-matching infrastructure to use CPU-type.

* Patch 9 cleans up the affected CPU list.

* Patch 10 uses the CPU-type to exclude P-only parts from the RFDS affected
  list.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
Pawan Gupta (4):
      x86/cpu: Name CPU matching macro more generically (and shorten)
      x86/cpu: Add cpu_type to struct x86_cpu_id
      x86/cpu: Update x86_match_cpu() to also use cpu-type
      x86/rfds: Exclude P-only parts from the RFDS affected list

 .../admin-guide/hw-vuln/reg-file-data-sampling.rst |   8 --
 arch/x86/include/asm/cpu_device_id.h               | 115 ++++++++-------------
 arch/x86/kernel/cpu/common.c                       |   7 +-
 arch/x86/kernel/cpu/match.c                        |  30 ++++++
 include/linux/mod_devicetable.h                    |   2 +
 5 files changed, 80 insertions(+), 82 deletions(-)
---
base-commit: 4f2a0b765c9731d2fa94e209ee9ae0e96b280f17
change-id: 20240617-add-cpu-type-4d5e47efc117

Best regards,
-- 
Pawan

[PATCH v7 1/4] x86/cpu: Name CPU matching macro more generically (and shorten)

[Pawan Gupta]

To add cpu-type to the existing CPU matching infrastructure, the base macro
X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE need to append _CPU_TYPE. This
makes an already long name longer, and somewhat incomprehensible.

To avoid this, rename the base macro to X86_MATCH_CPU. The macro name
doesn't need to explicitly tell everything that it matches. The arguments
to the macro already hints that.

For consistency, use this base macro to define X86_MATCH_VFM and friends.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
 arch/x86/include/asm/cpu_device_id.h | 101 ++++++++++-------------------------
 1 file changed, 29 insertions(+), 72 deletions(-)

diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h
index ba32e0f44cba..bb5acba69bd1 100644
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -57,7 +57,7 @@
 #define X86_CPU_ID_FLAG_ENTRY_VALID	BIT(0)
 
 /**
- * X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE - Base macro for CPU matching
+ * X86_MATCH_CPU -  Base macro for CPU matching
  * @_vendor:	The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
  *		The name is expanded to X86_VENDOR_@_vendor
  * @_family:	The family number or X86_FAMILY_ANY
@@ -74,19 +74,7 @@
  * into another macro at the usage site for good reasons, then please
  * start this local macro with X86_MATCH to allow easy grepping.
  */
-#define X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(_vendor, _family, _model, \
-						    _steppings, _feature, _data) { \
-	.vendor		= X86_VENDOR_##_vendor,				\
-	.family		= _family,					\
-	.model		= _model,					\
-	.steppings	= _steppings,					\
-	.feature	= _feature,					\
-	.flags		= X86_CPU_ID_FLAG_ENTRY_VALID,			\
-	.driver_data	= (unsigned long) _data				\
-}
-
-#define X86_MATCH_VENDORID_FAM_MODEL_STEPPINGS_FEATURE(_vendor, _family, _model, \
-						    _steppings, _feature, _data) { \
+#define X86_MATCH_CPU(_vendor, _family, _model, _steppings, _feature, _data) { \
 	.vendor		= _vendor,					\
 	.family		= _family,					\
 	.model		= _model,					\
@@ -106,13 +94,10 @@
  * @_data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is casted to unsigned long internally.
- *
- * The steppings arguments of X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE() is
- * set to wildcards.
  */
-#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data) \
-	X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(vendor, family, model, \
-						X86_STEPPING_ANY, feature, data)
+#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data)	\
+	X86_MATCH_CPU(X86_VENDOR_##vendor, family, model, X86_STEPPING_ANY,		\
+		      feature, data)
 
 /**
  * X86_MATCH_VENDOR_FAM_FEATURE - Macro for matching vendor, family and CPU feature
@@ -123,13 +108,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is casted to unsigned long internally.
- *
- * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
- * set to wildcards.
  */
-#define X86_MATCH_VENDOR_FAM_FEATURE(vendor, family, feature, data)	\
-	X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family,		\
-					   X86_MODEL_ANY, feature, data)
+#define X86_MATCH_VENDOR_FAM_FEATURE(vendor, family, feature, data)		\
+	X86_MATCH_CPU(X86_VENDOR_##vendor, family, X86_MODEL_ANY,		\
+		      X86_STEPPING_ANY, feature, data)
 
 /**
  * X86_MATCH_VENDOR_FEATURE - Macro for matching vendor and CPU feature
@@ -139,12 +121,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is casted to unsigned long internally.
- *
- * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
- * set to wildcards.
  */
-#define X86_MATCH_VENDOR_FEATURE(vendor, feature, data)			\
-	X86_MATCH_VENDOR_FAM_FEATURE(vendor, X86_FAMILY_ANY, feature, data)
+#define X86_MATCH_VENDOR_FEATURE(vendor, feature, data)				\
+	X86_MATCH_CPU(X86_VENDOR_##vendor, X86_FAMILY_ANY, X86_MODEL_ANY,	\
+		      X86_STEPPING_ANY, feature, data)
 
 /**
  * X86_MATCH_FEATURE - Macro for matching a CPU feature
@@ -152,12 +132,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is casted to unsigned long internally.
- *
- * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
- * set to wildcards.
  */
-#define X86_MATCH_FEATURE(feature, data)				\
-	X86_MATCH_VENDOR_FEATURE(ANY, feature, data)
+#define X86_MATCH_FEATURE(feature, data)					\
+	X86_MATCH_CPU(X86_VENDOR_ANY, X86_FAMILY_ANY, X86_MODEL_ANY,		\
+		      X86_STEPPING_ANY, feature, data)
 
 /**
  * X86_MATCH_VENDOR_FAM_MODEL - Match vendor, family and model
@@ -168,13 +146,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is casted to unsigned long internally.
- *
- * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
- * set to wildcards.
  */
-#define X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, data)		\
-	X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model,	\
-					   X86_FEATURE_ANY, data)
+#define X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, data)			\
+	X86_MATCH_CPU(X86_VENDOR_##vendor, family, model, X86_STEPPING_ANY,	\
+		      X86_FEATURE_ANY, data)
 
 /**
  * X86_MATCH_VENDOR_FAM - Match vendor and family
@@ -184,12 +159,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is casted to unsigned long internally.
- *
- * All other missing arguments to X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
- * set of wildcards.
  */
-#define X86_MATCH_VENDOR_FAM(vendor, family, data)			\
-	X86_MATCH_VENDOR_FAM_MODEL(vendor, family, X86_MODEL_ANY, data)
+#define X86_MATCH_VENDOR_FAM(vendor, family, data)				\
+	X86_MATCH_CPU(X86_VENDOR_##vendor, family, X86_MODEL_ANY,		\
+		      X86_STEPPING_ANY, X86_FEATURE_ANY, data)
 
 /**
  * X86_MATCH_VFM - Match encoded vendor/family/model
@@ -197,15 +170,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is cast to unsigned long internally.
- *
- * Stepping and feature are set to wildcards
  */
-#define X86_MATCH_VFM(vfm, data)			\
-	X86_MATCH_VENDORID_FAM_MODEL_STEPPINGS_FEATURE(	\
-		VFM_VENDOR(vfm),			\
-		VFM_FAMILY(vfm),			\
-		VFM_MODEL(vfm),				\
-		X86_STEPPING_ANY, X86_FEATURE_ANY, data)
+#define X86_MATCH_VFM(vfm, data)						\
+	X86_MATCH_CPU(VFM_VENDOR(vfm), VFM_FAMILY(vfm),	VFM_MODEL(vfm),		\
+		      X86_STEPPING_ANY, X86_FEATURE_ANY, data)
 
 #define __X86_STEPPINGS(mins, maxs)    GENMASK(maxs, mins)
 /**
@@ -215,16 +183,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is cast to unsigned long internally.
- *
- * feature is set to wildcard
  */
-#define X86_MATCH_VFM_STEPS(vfm, min_step, max_step, data)	\
-	X86_MATCH_VENDORID_FAM_MODEL_STEPPINGS_FEATURE(		\
-		VFM_VENDOR(vfm),				\
-		VFM_FAMILY(vfm),				\
-		VFM_MODEL(vfm),					\
-		__X86_STEPPINGS(min_step, max_step),		\
-		X86_FEATURE_ANY, data)
+#define X86_MATCH_VFM_STEPS(vfm, min_step, max_step, data)			\
+	X86_MATCH_CPU(VFM_VENDOR(vfm), VFM_FAMILY(vfm), VFM_MODEL(vfm),		\
+		      __X86_STEPPINGS(min_step, max_step), X86_FEATURE_ANY, data)
 
 /**
  * X86_MATCH_VFM_FEATURE - Match encoded vendor/family/model/feature
@@ -233,15 +195,10 @@
  * @data:	Driver specific data or NULL. The internal storage
  *		format is unsigned long. The supplied value, pointer
  *		etc. is cast to unsigned long internally.
- *
- * Steppings is set to wildcard
  */
-#define X86_MATCH_VFM_FEATURE(vfm, feature, data)	\
-	X86_MATCH_VENDORID_FAM_MODEL_STEPPINGS_FEATURE(	\
-		VFM_VENDOR(vfm),			\
-		VFM_FAMILY(vfm),			\
-		VFM_MODEL(vfm),				\
-		X86_STEPPING_ANY, feature, data)
+#define X86_MATCH_VFM_FEATURE(vfm, feature, data)				\
+	X86_MATCH_CPU(VFM_VENDOR(vfm), VFM_FAMILY(vfm), VFM_MODEL(vfm),		\
+		      X86_STEPPING_ANY, feature, data)
 
 extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
 extern bool x86_match_min_microcode_rev(const struct x86_cpu_id *table);

-- 
2.34.1

[PATCH v7 2/4] x86/cpu: Add cpu_type to struct x86_cpu_id

[Pawan Gupta]

In addition to matching vendor/family/model/feature, for hybrid variants it
is required to also match cpu-type also. For example some CPU
vulnerabilities like RFDS only affects a specific cpu-type.

To be able to also match CPUs based on their type, add a new field cpu_type
to struct x86_cpu_id which is used by the CPU-matching tables. Introduce
X86_CPU_TYPE_ANY for the cases that don't care about the cpu-type.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
 arch/x86/include/asm/cpu_device_id.h | 34 ++++++++++++++++++++++++----------
 include/linux/mod_devicetable.h      |  2 ++
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h
index bb5acba69bd1..20dd91146e75 100644
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -74,13 +74,14 @@
  * into another macro at the usage site for good reasons, then please
  * start this local macro with X86_MATCH to allow easy grepping.
  */
-#define X86_MATCH_CPU(_vendor, _family, _model, _steppings, _feature, _data) { \
+#define X86_MATCH_CPU(_vendor, _family, _model, _steppings, _feature, _cpu_type, _data) { \
 	.vendor		= _vendor,					\
 	.family		= _family,					\
 	.model		= _model,					\
 	.steppings	= _steppings,					\
 	.feature	= _feature,					\
 	.flags		= X86_CPU_ID_FLAG_ENTRY_VALID,			\
+	.cpu_type	= _cpu_type,					\
 	.driver_data	= (unsigned long) _data				\
 }
 
@@ -97,7 +98,7 @@
  */
 #define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data)	\
 	X86_MATCH_CPU(X86_VENDOR_##vendor, family, model, X86_STEPPING_ANY,		\
-		      feature, data)
+		      feature, X86_CPU_TYPE_ANY, data)
 
 /**
  * X86_MATCH_VENDOR_FAM_FEATURE - Macro for matching vendor, family and CPU feature
@@ -111,7 +112,7 @@
  */
 #define X86_MATCH_VENDOR_FAM_FEATURE(vendor, family, feature, data)		\
 	X86_MATCH_CPU(X86_VENDOR_##vendor, family, X86_MODEL_ANY,		\
-		      X86_STEPPING_ANY, feature, data)
+		      X86_STEPPING_ANY, feature, X86_CPU_TYPE_ANY, data)
 
 /**
  * X86_MATCH_VENDOR_FEATURE - Macro for matching vendor and CPU feature
@@ -124,7 +125,7 @@
  */
 #define X86_MATCH_VENDOR_FEATURE(vendor, feature, data)				\
 	X86_MATCH_CPU(X86_VENDOR_##vendor, X86_FAMILY_ANY, X86_MODEL_ANY,	\
-		      X86_STEPPING_ANY, feature, data)
+		      X86_STEPPING_ANY, feature, X86_CPU_TYPE_ANY, data)
 
 /**
  * X86_MATCH_FEATURE - Macro for matching a CPU feature
@@ -135,7 +136,7 @@
  */
 #define X86_MATCH_FEATURE(feature, data)					\
 	X86_MATCH_CPU(X86_VENDOR_ANY, X86_FAMILY_ANY, X86_MODEL_ANY,		\
-		      X86_STEPPING_ANY, feature, data)
+		      X86_STEPPING_ANY, feature, X86_CPU_TYPE_ANY, data)
 
 /**
  * X86_MATCH_VENDOR_FAM_MODEL - Match vendor, family and model
@@ -149,7 +150,7 @@
  */
 #define X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, data)			\
 	X86_MATCH_CPU(X86_VENDOR_##vendor, family, model, X86_STEPPING_ANY,	\
-		      X86_FEATURE_ANY, data)
+		      X86_FEATURE_ANY, X86_CPU_TYPE_ANY, data)
 
 /**
  * X86_MATCH_VENDOR_FAM - Match vendor and family
@@ -162,7 +163,7 @@
  */
 #define X86_MATCH_VENDOR_FAM(vendor, family, data)				\
 	X86_MATCH_CPU(X86_VENDOR_##vendor, family, X86_MODEL_ANY,		\
-		      X86_STEPPING_ANY, X86_FEATURE_ANY, data)
+		      X86_STEPPING_ANY, X86_FEATURE_ANY, X86_CPU_TYPE_ANY, data)
 
 /**
  * X86_MATCH_VFM - Match encoded vendor/family/model
@@ -173,7 +174,7 @@
  */
 #define X86_MATCH_VFM(vfm, data)						\
 	X86_MATCH_CPU(VFM_VENDOR(vfm), VFM_FAMILY(vfm),	VFM_MODEL(vfm),		\
-		      X86_STEPPING_ANY, X86_FEATURE_ANY, data)
+		      X86_STEPPING_ANY, X86_FEATURE_ANY, X86_CPU_TYPE_ANY, data)
 
 #define __X86_STEPPINGS(mins, maxs)    GENMASK(maxs, mins)
 /**
@@ -186,7 +187,8 @@
  */
 #define X86_MATCH_VFM_STEPS(vfm, min_step, max_step, data)			\
 	X86_MATCH_CPU(VFM_VENDOR(vfm), VFM_FAMILY(vfm), VFM_MODEL(vfm),		\
-		      __X86_STEPPINGS(min_step, max_step), X86_FEATURE_ANY, data)
+		      __X86_STEPPINGS(min_step, max_step), X86_FEATURE_ANY,	\
+		      X86_CPU_TYPE_ANY, data)
 
 /**
  * X86_MATCH_VFM_FEATURE - Match encoded vendor/family/model/feature
@@ -198,7 +200,19 @@
  */
 #define X86_MATCH_VFM_FEATURE(vfm, feature, data)				\
 	X86_MATCH_CPU(VFM_VENDOR(vfm), VFM_FAMILY(vfm), VFM_MODEL(vfm),		\
-		      X86_STEPPING_ANY, feature, data)
+		      X86_STEPPING_ANY, feature, X86_CPU_TYPE_ANY, data)
+
+/**
+ * X86_MATCH_VFM_CPU_TYPE - Match encoded vendor/family/model/cpu-type
+ * @vfm:	Encoded 8-bits each for vendor, family, model
+ * @cpu_type:	CPU type e.g. P-core, E-core on Intel
+ * @data:	Driver specific data or NULL. The internal storage
+ *		format is unsigned long. The supplied value, pointer
+ *		etc. is cast to unsigned long internally.
+ */
+#define X86_MATCH_VFM_CPU_TYPE(vfm, cpu_type, data)			\
+	X86_MATCH_CPU(VFM_VENDOR(vfm), VFM_FAMILY(vfm), VFM_MODEL(vfm),	\
+		      X86_STEPPING_ANY, X86_FEATURE_ANY, cpu_type, data)
 
 extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
 extern bool x86_match_min_microcode_rev(const struct x86_cpu_id *table);
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index d67614f7b7f1..18e996acb49a 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -692,6 +692,7 @@ struct x86_cpu_id {
 	__u16 feature;	/* bit index */
 	/* Solely for kernel-internal use: DO NOT EXPORT to userspace! */
 	__u16 flags;
+	__u8  cpu_type;
 	kernel_ulong_t driver_data;
 };
 
@@ -703,6 +704,7 @@ struct x86_cpu_id {
 #define X86_STEP_MIN 0
 #define X86_STEP_MAX 0xf
 #define X86_FEATURE_ANY 0	/* Same as FPU, you can't test for that */
+#define X86_CPU_TYPE_ANY 0
 
 /*
  * Generic table type for matching CPU features.

-- 
2.34.1

[PATCH v7 3/4] x86/cpu: Update x86_match_cpu() to also use cpu-type

[Pawan Gupta]

Non-hybrid CPU variants that share the same Family/Model could be
differentiated by their cpu-type. x86_match_cpu() currently does not use
cpu-type for CPU matching.

Dave Hansen suggested to use below conditions to match CPU-type:

  1. If CPU_TYPE_ANY (the wildcard), then matched
  2. If hybrid, then matched
  3. If !hybrid, look at the boot CPU and compare the cpu-type to determine
     if it is a match.

  This special case for hybrid systems allows more compact vulnerability
  list.  Imagine that "Haswell" CPUs might or might not be hybrid and that
  only Atom cores are vulnerable to Meltdown.  That means there are three
  possibilities:

  	1. P-core only
  	2. Atom only
  	3. Atom + P-core (aka. hybrid)

  One might be tempted to code up the vulnerability list like this:

  	MATCH(     HASWELL, X86_FEATURE_HYBRID, MELTDOWN)
  	MATCH_TYPE(HASWELL, ATOM,               MELTDOWN)

  Logically, this matches #2 and #3. But that's a little silly. You would
  only ask for the "ATOM" match in cases where there *WERE* hybrid cores in
  play. You shouldn't have to _also_ ask for hybrid cores explicitly.

  In short, assume that processors that enumerate Hybrid==1 have a
  vulnerable core type.

Update x86_match_cpu() to also match cpu-type. Also treat hybrid systems as
special, and match them to any cpu-type.

Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
 arch/x86/kernel/cpu/match.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index 4f3c65429f82..4b052860b774 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -5,6 +5,34 @@
 #include <linux/export.h>
 #include <linux/slab.h>
 
+/**
+ * x86_match_vendor_cpu_type - helper function to match the hardware defined
+ *                             cpu-type for a single entry in the x86_cpu_id
+ *                             table. Note, this function does not match the
+ *                             generic cpu-types TOPO_CPU_TYPE_EFFICIENCY and
+ *                             TOPO_CPU_TYPE_PERFORMANCE.
+ * @c: Pointer to the cpuinfo_x86 structure of the CPU to match.
+ * @m: Pointer to the x86_cpu_id entry to match against.
+ *
+ * Return: true if the cpu-type matches, false otherwise.
+ */
+static bool x86_match_vendor_cpu_type(struct cpuinfo_x86 *c, const struct x86_cpu_id *m)
+{
+	if (m->cpu_type == X86_CPU_TYPE_ANY)
+		return true;
+
+	/* Hybrid CPUs are special, they are assumed to match all cpu-types */
+	if (boot_cpu_has(X86_FEATURE_HYBRID_CPU))
+		return true;
+
+	if (c->x86_vendor == X86_VENDOR_INTEL)
+		return m->cpu_type == c->topo.intel_type;
+	if (c->x86_vendor == X86_VENDOR_AMD)
+		return m->cpu_type == c->topo.amd_type;
+
+	return false;
+}
+
 /**
  * x86_match_cpu - match current CPU against an array of x86_cpu_ids
  * @match: Pointer to array of x86_cpu_ids. Last entry terminated with
@@ -50,6 +78,8 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
 			continue;
 		if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
 			continue;
+		if (!x86_match_vendor_cpu_type(c, m))
+			continue;
 		return m;
 	}
 	return NULL;

-- 
2.34.1

[PATCH v7 4/4] x86/rfds: Exclude P-only parts from the RFDS affected list

[Pawan Gupta]

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.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
 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 0585d02b9a6c..ad15417d39f9 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 5f81c553e733..92fe56c40238 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),

-- 
2.34.1

Re: [PATCH v7 1/4] x86/cpu: Name CPU matching macro more generically (and shorten)

[Borislav Petkov]

On Thu, Mar 06, 2025 at 06:18:03PM -0800, Pawan Gupta wrote:
> @@ -106,13 +94,10 @@
>   * @_data:	Driver specific data or NULL. The internal storage
>   *		format is unsigned long. The supplied value, pointer
>   *		etc. is casted to unsigned long internally.
> - *
> - * The steppings arguments of X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE() is
> - * set to wildcards.
>   */
> -#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data) \
> -	X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(vendor, family, model, \
> -						X86_STEPPING_ANY, feature, data)
> +#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data)	\
> +	X86_MATCH_CPU(X86_VENDOR_##vendor, family, model, X86_STEPPING_ANY,		\
> +		      feature, data)
>  

That one is unused. Zap it.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH v7 2/4] x86/cpu: Add cpu_type to struct x86_cpu_id

[Borislav Petkov]

On Thu, Mar 06, 2025 at 06:18:20PM -0800, Pawan Gupta wrote:
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index d67614f7b7f1..18e996acb49a 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -692,6 +692,7 @@ struct x86_cpu_id {
>  	__u16 feature;	/* bit index */
>  	/* Solely for kernel-internal use: DO NOT EXPORT to userspace! */
>  	__u16 flags;
> +	__u8  cpu_type;

The struct is called "x86_cpu_id" and all its members describe a CPU. There's
no need to have more "cpu_" redundancy in the member names - just call that
"type".  It is clear that it is about a CPU's type.

The macro names having "CPU" - X86_CPU_TYPE_ANY - are fine I guess.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH v7 3/4] x86/cpu: Update x86_match_cpu() to also use cpu-type

[Borislav Petkov]

On Thu, Mar 06, 2025 at 06:18:36PM -0800, Pawan Gupta wrote:
> +static bool x86_match_vendor_cpu_type(struct cpuinfo_x86 *c, const struct x86_cpu_id *m)
> +{
> +	if (m->cpu_type == X86_CPU_TYPE_ANY)
> +		return true;
> +
> +	/* Hybrid CPUs are special, they are assumed to match all cpu-types */
> +	if (boot_cpu_has(X86_FEATURE_HYBRID_CPU))

check_for_deprecated_apis: WARNING: arch/x86/kernel/cpu/match.c:25: Do not use boot_cpu_has() - use cpu_feature_enabled() instead.

> +		return true;
> +
> +	if (c->x86_vendor == X86_VENDOR_INTEL)
> +		return m->cpu_type == c->topo.intel_type;
> +	if (c->x86_vendor == X86_VENDOR_AMD)
> +		return m->cpu_type == c->topo.amd_type;
> +
> +	return false;
> +}

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH v7 1/4] x86/cpu: Name CPU matching macro more generically (and shorten)

[Pawan Gupta]

On Sun, Mar 09, 2025 at 06:29:20PM +0100, Borislav Petkov wrote:
> On Thu, Mar 06, 2025 at 06:18:03PM -0800, Pawan Gupta wrote:
> > @@ -106,13 +94,10 @@
> >   * @_data:	Driver specific data or NULL. The internal storage
> >   *		format is unsigned long. The supplied value, pointer
> >   *		etc. is casted to unsigned long internally.
> > - *
> > - * The steppings arguments of X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE() is
> > - * set to wildcards.
> >   */
> > -#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data) \
> > -	X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(vendor, family, model, \
> > -						X86_STEPPING_ANY, feature, data)
> > +#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data)	\
> > +	X86_MATCH_CPU(X86_VENDOR_##vendor, family, model, X86_STEPPING_ANY,		\
> > +		      feature, data)
> >  
> 
> That one is unused. Zap it.

Correct. I will remove it.

Re: [PATCH v7 2/4] x86/cpu: Add cpu_type to struct x86_cpu_id

[Pawan Gupta]

On Sun, Mar 09, 2025 at 06:32:39PM +0100, Borislav Petkov wrote:
> On Thu, Mar 06, 2025 at 06:18:20PM -0800, Pawan Gupta wrote:
> > diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> > index d67614f7b7f1..18e996acb49a 100644
> > --- a/include/linux/mod_devicetable.h
> > +++ b/include/linux/mod_devicetable.h
> > @@ -692,6 +692,7 @@ struct x86_cpu_id {
> >  	__u16 feature;	/* bit index */
> >  	/* Solely for kernel-internal use: DO NOT EXPORT to userspace! */
> >  	__u16 flags;
> > +	__u8  cpu_type;
> 
> The struct is called "x86_cpu_id" and all its members describe a CPU. There's
> no need to have more "cpu_" redundancy in the member names - just call that
> "type".  It is clear that it is about a CPU's type.

Makes sense, I will change it to "type".

Re: [PATCH v7 3/4] x86/cpu: Update x86_match_cpu() to also use cpu-type

[Pawan Gupta]

On Mon, Mar 10, 2025 at 11:48:44AM +0100, Borislav Petkov wrote:
> On Thu, Mar 06, 2025 at 06:18:36PM -0800, Pawan Gupta wrote:
> > +static bool x86_match_vendor_cpu_type(struct cpuinfo_x86 *c, const struct x86_cpu_id *m)
> > +{
> > +	if (m->cpu_type == X86_CPU_TYPE_ANY)
> > +		return true;
> > +
> > +	/* Hybrid CPUs are special, they are assumed to match all cpu-types */
> > +	if (boot_cpu_has(X86_FEATURE_HYBRID_CPU))
> 
> check_for_deprecated_apis: WARNING: arch/x86/kernel/cpu/match.c:25: Do not use boot_cpu_has() - use cpu_feature_enabled() instead.

Will do. Thanks for the review.