[xen master] x86: replace APERFMPERF synthetic feature bit

[patchbot@xxxxxxx]

commit e09aa8610589924c90e0e657a7fa2f61762ded8f
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Jan 20 09:00:01 2026 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Jan 20 09:00:01 2026 +0100

    x86: replace APERFMPERF synthetic feature bit
    
    Use the respective host CPU policy bit instead. This has the (tolerable,
    as we generally assume symmetry anyway) effect of using the BSP's
    (unleveled) setting, rather than the result of leveling (as is done by
    identify_cpu() on boot_cpu_data, rendering the variable name somewhat
    misleading).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Jason Andryuk <jason.andryuk@xxxxxxx>
---
 xen/arch/x86/acpi/cpufreq/cpufreq.c    | 2 +-
 xen/arch/x86/cpu/common.c              | 4 ----
 xen/arch/x86/include/asm/cpufeature.h  | 7 +++++--
 xen/arch/x86/include/asm/cpufeatures.h | 2 +-
 4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/acpi/cpufreq/cpufreq.c 
b/xen/arch/x86/acpi/cpufreq/cpufreq.c
index 94e8e11c15..7d522f84ac 100644
--- a/xen/arch/x86/acpi/cpufreq/cpufreq.c
+++ b/xen/arch/x86/acpi/cpufreq/cpufreq.c
@@ -80,7 +80,7 @@ unsigned int get_measured_perf(unsigned int cpu, unsigned int 
flag)
         return 0;
 
     policy = per_cpu(cpufreq_cpu_policy, cpu);
-    if ( !policy || !cpu_has_aperfmperf )
+    if ( !policy || !cpu_has_hw_feedback_cap )
         return 0;
 
     switch (flag)
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 37820a3a08..091c018934 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -523,10 +523,6 @@ static void generic_identify(struct cpuinfo_x86 *c)
        if ( cpu_has(c, X86_FEATURE_CLFLUSH) )
                c->x86_clflush_size = ((ebx >> 8) & 0xff) * 8;
 
-       if ( (c->cpuid_level >= CPUID_PM_LEAF) &&
-            (cpuid_ecx(CPUID_PM_LEAF) & CPUID6_ECX_APERFMPERF_CAPABILITY) )
-               __set_bit(X86_FEATURE_APERFMPERF, c->x86_capability);
-
        /* AMD-defined flags: level 0x80000001 */
        if (c->extended_cpuid_level >= 0x80000001)
                cpuid(0x80000001, &tmp, &tmp,
diff --git a/xen/arch/x86/include/asm/cpufeature.h 
b/xen/arch/x86/include/asm/cpufeature.h
index 28c4085cc7..8423f54723 100644
--- a/xen/arch/x86/include/asm/cpufeature.h
+++ b/xen/arch/x86/include/asm/cpufeature.h
@@ -11,7 +11,9 @@
 #include <xen/macros.h>
 
 #ifndef __ASSEMBLER__
+#include <asm/cpu-policy.h>
 #include <asm/cpuid.h>
+#include <xen/lib/x86/cpu-policy.h>
 #else
 #include <asm/cpufeatureset.h>
 #endif
@@ -121,7 +123,6 @@ static inline bool boot_cpu_has(unsigned int feat)
 #define CPUID6_EAX_HDC                               BIT(13, U)
 #define CPUID6_EAX_HWP_PECI                          BIT(16, U)
 #define CPUID6_EAX_HW_FEEDBACK                       BIT(19, U)
-#define CPUID6_ECX_APERFMPERF_CAPABILITY             BIT(0, U)
 
 /* CPUID level 0x00000001.edx */
 #define cpu_has_fpu             1
@@ -175,6 +176,9 @@ static inline bool boot_cpu_has(unsigned int feat)
 #define cpu_has_fma4            boot_cpu_has(X86_FEATURE_FMA4)
 #define cpu_has_tbm             boot_cpu_has(X86_FEATURE_TBM)
 
+/* CPUID level 0x00000006.ecx */
+#define cpu_has_hw_feedback_cap host_cpu_policy.basic.hw_feedback_cap
+
 /* CPUID level 0x0000000D:1.eax */
 #define cpu_has_xsaveopt        boot_cpu_has(X86_FEATURE_XSAVEOPT)
 #define cpu_has_xsavec          boot_cpu_has(X86_FEATURE_XSAVEC)
@@ -292,7 +296,6 @@ static inline bool boot_cpu_has(unsigned int feat)
 /* Synthesized. */
 #define cpu_has_arch_perfmon    boot_cpu_has(X86_FEATURE_ARCH_PERFMON)
 #define cpu_has_cpuid_faulting  boot_cpu_has(X86_FEATURE_CPUID_FAULTING)
-#define cpu_has_aperfmperf      boot_cpu_has(X86_FEATURE_APERFMPERF)
 #define cpu_has_xen_lbr         boot_cpu_has(X86_FEATURE_XEN_LBR)
 #define cpu_has_xen_shstk       (IS_ENABLED(CONFIG_XEN_SHSTK) && \
                                  boot_cpu_has(X86_FEATURE_XEN_SHSTK))
diff --git a/xen/arch/x86/include/asm/cpufeatures.h 
b/xen/arch/x86/include/asm/cpufeatures.h
index bd53ba7976..0d90924e3e 100644
--- a/xen/arch/x86/include/asm/cpufeatures.h
+++ b/xen/arch/x86/include/asm/cpufeatures.h
@@ -19,7 +19,7 @@ XEN_CPUFEATURE(TSC_RELIABLE,      X86_SYNTH( 4)) /* TSC is 
known to be reliable
 XEN_CPUFEATURE(XTOPOLOGY,         X86_SYNTH( 5)) /* cpu topology enum 
extensions */
 XEN_CPUFEATURE(CPUID_FAULTING,    X86_SYNTH( 6)) /* cpuid faulting */
 XEN_CPUFEATURE(XEN_FRED,          X86_SYNTH( 7)) /* Xen uses FRED */
-XEN_CPUFEATURE(APERFMPERF,        X86_SYNTH( 8)) /* APERFMPERF */
+/* Bit 8 unused */
 XEN_CPUFEATURE(MFENCE_RDTSC,      X86_SYNTH( 9)) /* MFENCE synchronizes RDTSC 
*/
 XEN_CPUFEATURE(XEN_SMEP,          X86_SYNTH(10)) /* SMEP gets used by Xen 
itself */
 XEN_CPUFEATURE(XEN_SMAP,          X86_SYNTH(11)) /* SMAP gets used by Xen 
itself */
--
generated by git-patchbot for /home/xen/git/xen.git#master