diff --git a/sys/conf/files.amd64 b/sys/conf/files.amd64
--- a/sys/conf/files.amd64
+++ b/sys/conf/files.amd64
@@ -418,6 +418,7 @@
 # config(8) doesn't have a way to force standard options, so we've been inconsistent
 # about marking non-optional things 'standard'.
 x86/acpica/madt.c		optional	acpi
+x86/acpica/acpi_cppc_platform.c		optional	acpi
 x86/isa/atpic.c			optional	atpic isa
 x86/isa/elcr.c			optional	atpic isa | mptable
 x86/isa/isa.c			standard
diff --git a/sys/x86/acpica/acpi_cppc_platform.c b/sys/x86/acpica/acpi_cppc_platform.c
new file mode 100644
--- /dev/null
+++ b/sys/x86/acpica/acpi_cppc_platform.c
@@ -0,0 +1,67 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2026 ShengYi Hung <aokblast@FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#include <sys/param.h>
+#include <sys/bus.h>
+#include <sys/cpu.h>
+#include <sys/rman.h>
+
+#include <machine/acpica_machdep.h>
+#include <x86/x86_var.h>
+#include <machine/bus.h>
+
+#include <contrib/dev/acpica/include/acpi.h>
+
+#include <dev/acpica/acpivar.h>
+#include <dev/acpica/acpi_cppc_lib.h>
+
+uint64_t
+acpi_cppc_ffh_read(device_t dev, struct acpi_cppc_ffh *ffh)
+{
+	uint64_t val = 0;
+
+	/*
+	 * The MSR index comes from firmware (_CPC/_PCT), so use the _SAFE
+	 * variant: a bogus register must not panic the machine.  On a fault
+	 * the value is left at 0.
+	 */
+	(void)x86_msr_op(ffh->address,
+	    MSR_OP_RENDEZVOUS_ONE | MSR_OP_READ | MSR_OP_SAFE |
+		MSR_OP_CPUID(cpu_get_pcpu(dev)->pc_cpuid),
+	    0, &val);
+	return (val);
+}
+
+void
+acpi_cppc_ffh_write(device_t dev, struct acpi_cppc_ffh *ffh, uint64_t val)
+{
+	(void)x86_msr_op(ffh->address,
+	    MSR_OP_RENDEZVOUS_ONE | MSR_OP_WRITE | MSR_OP_SAFE |
+		MSR_OP_CPUID(cpu_get_pcpu(dev)->pc_cpuid),
+	    val, NULL);
+}
diff --git a/sys/x86/include/acpica_machdep.h b/sys/x86/include/acpica_machdep.h
--- a/sys/x86/include/acpica_machdep.h
+++ b/sys/x86/include/acpica_machdep.h
@@ -86,6 +86,11 @@
 
 void	acpi_set_root(vm_paddr_t addr);
 
+#define ACPI_CPPC_FFH
+struct acpi_cppc_ffh;
+uint64_t acpi_cppc_ffh_read(device_t dev, struct acpi_cppc_ffh *ffh);
+void acpi_cppc_ffh_write(device_t dev, struct acpi_cppc_ffh *, uint64_t val);
+
 #endif /* _KERNEL */
 
 #endif /* __ACPICA_MACHDEP_H__ */