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[PATCH 5/5] cpufreq/amd-cppc: move pxfreq_mhz into driver data


  • To: "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Thu, 22 Jan 2026 10:43:50 +0100
  • Autocrypt: addr=jbeulich@xxxxxxxx; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL
  • Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Penny Zheng <Penny.Zheng@xxxxxxx>
  • Delivery-date: Thu, 22 Jan 2026 09:48:14 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

No reason for it to be a separate per-CPU item; it's connected to a
struct cpufreq_policy instance just like other driver data.

This also eliminates the concern over amd_cppc_cpufreq_cpu_init() being
called for all CPUs, or a CPU going offline that's recorded in policy->cpu
(which would result in accesses of per-CPU data of offline CPUs).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/acpi/cpufreq/amd-cppc.c
+++ b/xen/arch/x86/acpi/cpufreq/amd-cppc.c
@@ -30,11 +30,6 @@
         printk(XENLOG_DEBUG "AMD-CPPC: CPU%u " fmt, cpu, ## args);  \
 })
 
-/*
- * Core max frequency read from PstateDef as anchor point
- * for freq-to-perf transition
- */
-static DEFINE_PER_CPU_READ_MOSTLY(unsigned int, pxfreq_mhz);
 #ifndef NDEBUG
 static bool __ro_after_init opt_active_mode;
 #else
@@ -117,7 +112,7 @@ static int amd_cppc_khz_to_perf(const st
     {
         /* Read Processor Max Speed(MHz) as anchor point */
         mul = data->caps.highest_perf;
-        div = this_cpu(pxfreq_mhz);
+        div = data->pxfreq_mhz;
         if ( !div )
             return -EOPNOTSUPP;
     }
@@ -160,7 +155,7 @@ static int amd_get_cpc_freq(const struct
     }
 
     /* Read Processor Max Speed(MHz) as anchor point */
-    mul = this_cpu(pxfreq_mhz);
+    mul = data->pxfreq_mhz;
     if ( !mul )
         return -EOPNOTSUPP;
     div = data->caps.highest_perf;
@@ -287,7 +282,7 @@ static void cf_check amd_cppc_init_msrs(
     }
 
     amd_process_freq(&cpu_data[policy->cpu],
-                     NULL, NULL, &this_cpu(pxfreq_mhz));
+                     NULL, NULL, &data->pxfreq_mhz);
 
     data->err = amd_get_cpc_freq(data, data->cppc_data->cpc.lowest_mhz,
                                  data->caps.lowest_perf, &min_freq);
--- a/xen/include/acpi/cpufreq/cpufreq.h
+++ b/xen/include/acpi/cpufreq/cpufreq.h
@@ -145,6 +145,12 @@ struct amd_cppc_drv_data {
 
     uint8_t epp_init;
 
+    /*
+     * Core max frequency read from PstateDef as anchor point
+     * for freq-to-perf transition
+     */
+    unsigned int pxfreq_mhz;
+
     int err;
 };
 




 


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