--- /dev/null
+/*
+ * Copyright 2012 by Oracle Inc
+ * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+ *
+ * This code borrows ideas from https://lkml.org/lkml/2011/11/30/249
+ * so many thanks go to Kevin Tian <kevin.tian@intel.com>
+ * and Yu Ke <ke.yu@intel.com>.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/cpumask.h>
+#include <linux/cpufreq.h>
+#include <linux/freezer.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+#include <acpi/processor.h>
+
+#include <xen/interface/platform.h>
+#include <asm/xen/hypercall.h>
+
+#define DRV_NAME "cpufreq-xen"
+
+static int no_hypercall;
+MODULE_PARM_DESC(off, "Inhibit the hypercall.");
+module_param_named(off, no_hypercall, int, 0400);
+
+/*
+ * Mutex to protect the acpi_ids_done.
+ */
+static DEFINE_MUTEX(acpi_ids_mutex);
+/*
+ * Don't think convert this to cpumask_var_t or use cpumask_bit - as those
+ * shrink to nr_cpu_bits (which is dependent on possible_cpu), which can be
+ * less than what we want to put in.
+ */
+#define NR_ACPI_CPUS NR_CPUS
+#define MAX_ACPI_BITS (BITS_TO_LONGS(NR_ACPI_CPUS))
+static unsigned long *acpi_ids_done;
+/*
+ * Again, don't convert to cpumask - as we are reading the raw ACPI CPU ids
+ * which can go beyond what we presently see.
+ */
+static unsigned long *acpi_id_present;
+
+/*
+ * Pertient data for the timer to be launched to check if the # of
+ * ACPI CPU ids is different from the one we have processed.
+ */
+#define DELAY_TIMER msecs_to_jiffies(5000 /* 5 sec */)
+static struct acpi_processor *pr_backup;
+static struct delayed_work work;
+
+static int push_cxx_to_hypervisor(struct acpi_processor *_pr)
+{
+ struct xen_platform_op op = {
+ .cmd = XENPF_set_processor_pminfo,
+ .interface_version = XENPF_INTERFACE_VERSION,
+ .u.set_pminfo.id = _pr->acpi_id,
+ .u.set_pminfo.type = XEN_PM_CX,
+ };
+ struct xen_processor_cx *dst_cx, *dst_cx_states = NULL;
+ struct acpi_processor_cx *cx;
+ int i, ok, ret = 0;
+
+ dst_cx_states = kcalloc(_pr->power.count,
+ sizeof(struct xen_processor_cx), GFP_KERNEL);
+ if (!dst_cx_states)
+ return -ENOMEM;
+
+ for (ok = 0, i = 1; i <= _pr->power.count; i++) {
+ cx = &_pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ dst_cx = &(dst_cx_states[ok++]);
+
+ dst_cx->reg.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
+ if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
+ dst_cx->reg.bit_width = 8;
+ dst_cx->reg.bit_offset = 0;
+ dst_cx->reg.access_size = 1;
+ } else {
+ dst_cx->reg.space_id = ACPI_ADR_SPACE_FIXED_HARDWARE;
+ if (cx->entry_method == ACPI_CSTATE_FFH) {
+ /* NATIVE_CSTATE_BEYOND_HALT */
+ dst_cx->reg.bit_offset = 2;
+ dst_cx->reg.bit_width = 1; /* VENDOR_INTEL */
+ }
+ dst_cx->reg.access_size = 0;
+ }
+ dst_cx->reg.address = cx->address;
+
+ dst_cx->type = cx->type;
+ dst_cx->latency = cx->latency;
+ dst_cx->power = cx->power;
+
+ dst_cx->dpcnt = 0;
+ set_xen_guest_handle(dst_cx->dp, NULL);
+#ifdef DEBUG
+ pr_debug(DRV_NAME ": CX: ID:%d [C%d:%s] entry:%d\n",
+ _pr->acpi_id, cx->type, cx->desc, cx->entry_method);
+#endif
+ }
+ if (!ok) {
+ pr_err(DRV_NAME ": No _Cx for CPU %d\n", _pr->acpi_id);
+ kfree(dst_cx_states);
+ return -EINVAL;
+ }
+ op.u.set_pminfo.power.count = ok;
+ op.u.set_pminfo.power.flags.bm_control = _pr->flags.bm_control;
+ op.u.set_pminfo.power.flags.bm_check = _pr->flags.bm_check;
+ op.u.set_pminfo.power.flags.has_cst = _pr->flags.has_cst;
+ op.u.set_pminfo.power.flags.power_setup_done =
+ _pr->flags.power_setup_done;
+
+ set_xen_guest_handle(op.u.set_pminfo.power.states, dst_cx_states);
+
+ if (!no_hypercall)
+ ret = HYPERVISOR_dom0_op(&op);
+
+ if (ret)
+ pr_err(DRV_NAME "(CX): Hypervisor error (%d) for ACPI ID: %d\n",
+ ret, _pr->acpi_id);
+
+ kfree(dst_cx_states);
+
+ return ret;
+}
+static struct xen_processor_px *
+xen_copy_pss_data(struct acpi_processor *_pr,
+ struct xen_processor_performance *dst_perf)
+{
+ struct xen_processor_px *dst_states = NULL;
+ int i;
+
+ BUILD_BUG_ON(sizeof(struct xen_processor_px) !=
+ sizeof(struct acpi_processor_px));
+
+ dst_states = kcalloc(_pr->performance->state_count,
+ sizeof(struct xen_processor_px), GFP_KERNEL);
+ if (!dst_states)
+ return ERR_PTR(-ENOMEM);
+
+ dst_perf->state_count = _pr->performance->state_count;
+ for (i = 0; i < _pr->performance->state_count; i++) {
+ /* Fortunatly for us, they are both the same size */
+ memcpy(&(dst_states[i]), &(_pr->performance->states[i]),
+ sizeof(struct acpi_processor_px));
+ }
+ return dst_states;
+}
+static int xen_copy_psd_data(struct acpi_processor *_pr,
+ struct xen_processor_performance *dst)
+{
+ BUILD_BUG_ON(sizeof(struct xen_psd_package) !=
+ sizeof(struct acpi_psd_package));
+
+ if (_pr->performance->shared_type != CPUFREQ_SHARED_TYPE_NONE) {
+ dst->shared_type = _pr->performance->shared_type;
+
+ memcpy(&(dst->domain_info), &(_pr->performance->domain_info),
+ sizeof(struct acpi_psd_package));
+ } else {
+ if ((&cpu_data(0))->x86_vendor != X86_VENDOR_AMD)
+ return -EINVAL;
+
+ /* On AMD, the powernow-k8 is loaded before acpi_cpufreq
+ * meaning that acpi_processor_preregister_performance never
+ * gets called which would parse the _PSD. The only relevant
+ * information from _PSD we need is whether it is HW_ALL or any
+ * other type. AMD K8 >= are SW_ALL or SW_ANY, AMD K7<= HW_ANY.
+ * This driver checks at the start whether it is K8 so it
+ * if we get here it can only be K8.
+ */
+ dst->shared_type = CPUFREQ_SHARED_TYPE_ANY;
+ dst->domain_info.coord_type = DOMAIN_COORD_TYPE_SW_ANY;
+ dst->domain_info.num_processors = num_online_cpus();
+ }
+ return 0;
+}
+static int xen_copy_pct_data(struct acpi_pct_register *pct,
+ struct xen_pct_register *dst_pct)
+{
+ /* It would be nice if you could just do 'memcpy(pct, dst_pct') but
+ * sadly the Xen structure did not have the proper padding so the
+ * descriptor field takes two (dst_pct) bytes instead of one (pct).
+ */
+ dst_pct->descriptor = pct->descriptor;
+ dst_pct->length = pct->length;
+ dst_pct->space_id = pct->space_id;
+ dst_pct->bit_width = pct->bit_width;
+ dst_pct->bit_offset = pct->bit_offset;
+ dst_pct->reserved = pct->reserved;
+ dst_pct->address = pct->address;
+ return 0;
+}
+static int push_pxx_to_hypervisor(struct acpi_processor *_pr)
+{
+ int ret = 0;
+ struct xen_platform_op op = {
+ .cmd = XENPF_set_processor_pminfo,
+ .interface_version = XENPF_INTERFACE_VERSION,
+ .u.set_pminfo.id = _pr->acpi_id,
+ .u.set_pminfo.type = XEN_PM_PX,
+ };
+ struct xen_processor_performance *dst_perf;
+ struct xen_processor_px *dst_states = NULL;
+
+ dst_perf = &op.u.set_pminfo.perf;
+
+ dst_perf->platform_limit = _pr->performance_platform_limit;
+ dst_perf->flags |= XEN_PX_PPC;
+ xen_copy_pct_data(&(_pr->performance->control_register),
+ &dst_perf->control_register);
+ xen_copy_pct_data(&(_pr->performance->status_register),
+ &dst_perf->status_register);
+ dst_perf->flags |= XEN_PX_PCT;
+ dst_states = xen_copy_pss_data(_pr, dst_perf);
+ if (!IS_ERR_OR_NULL(dst_states)) {
+ set_xen_guest_handle(dst_perf->states, dst_states);
+ dst_perf->flags |= XEN_PX_PSS;
+ }
+ if (!xen_copy_psd_data(_pr, dst_perf))
+ dst_perf->flags |= XEN_PX_PSD;
+
+ if (!no_hypercall)
+ ret = HYPERVISOR_dom0_op(&op);
+
+ if (ret)
+ pr_err(DRV_NAME "(_PXX): Hypervisor error (%d) for ACPI ID %d\n",
+ ret, _pr->acpi_id);
+
+ if (!IS_ERR_OR_NULL(dst_states))
+ kfree(dst_states);
+
+ return ret;
+}
+static int upload_pm_data(struct acpi_processor *_pr)
+{
+ int err = 0;
+
+ if (__test_and_set_bit(_pr->acpi_id, acpi_ids_done))
+ return -EBUSY;
+
+ if (_pr->flags.power)
+ err = push_cxx_to_hypervisor(_pr);
+
+ if (_pr->performance && _pr->performance->states)
+ err |= push_pxx_to_hypervisor(_pr);
+
+ return err;
+}
+static acpi_status
+read_acpi_id(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+ u32 acpi_id;
+ acpi_status status;
+ acpi_object_type acpi_type;
+ unsigned long long tmp;
+ union acpi_object object = { 0 };
+ struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
+
+ status = acpi_get_type(handle, &acpi_type);
+ if (ACPI_FAILURE(status))
+ return AE_OK;
+
+ switch (acpi_type) {
+ case ACPI_TYPE_PROCESSOR:
+ status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
+ if (ACPI_FAILURE(status))
+ return AE_OK;
+ acpi_id = object.processor.proc_id;
+ break;
+ case ACPI_TYPE_DEVICE:
+ status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
+ if (ACPI_FAILURE(status))
+ return AE_OK;
+ acpi_id = tmp;
+ break;
+ default:
+ return AE_OK;
+ }
+ if (acpi_id > NR_ACPI_CPUS) {
+ WARN_ONCE(1, "There are %d ACPI processors, but kernel can only do %d!\n",
+ acpi_id, NR_ACPI_CPUS);
+ return AE_OK;
+ }
+ __set_bit(acpi_id, acpi_id_present);
+
+ return AE_OK;
+}
+static unsigned int more_acpi_ids(void)
+{
+ unsigned int n = 0;
+
+ acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
+ ACPI_UINT32_MAX,
+ read_acpi_id, NULL, NULL, NULL);
+ acpi_get_devices("ACPI0007", read_acpi_id, NULL, NULL);
+
+ mutex_lock(&acpi_ids_mutex);
+ if (!bitmap_equal(acpi_id_present, acpi_ids_done, MAX_ACPI_BITS))
+ n = bitmap_weight(acpi_id_present, MAX_ACPI_BITS);
+ mutex_unlock(&acpi_ids_mutex);
+
+ return n;
+}
+static void do_check_acpi_id_timer(struct work_struct *_work)
+{
+ /* All online CPUs have been processed at this stage. Now verify
+ * whether in fact "online CPUs" == physical CPUs.
+ */
+ acpi_id_present = kcalloc(MAX_ACPI_BITS, sizeof(unsigned long), GFP_KERNEL);
+ if (!acpi_id_present)
+ return;
+ memset(acpi_id_present, 0, MAX_ACPI_BITS * sizeof(unsigned long));
+
+ if (more_acpi_ids()) {
+ int cpu;
+ if (!pr_backup) {
+ schedule_delayed_work(&work, DELAY_TIMER);
+ return;
+ }
+ for_each_set_bit(cpu, acpi_id_present, MAX_ACPI_BITS) {
+ pr_backup->acpi_id = cpu;
+ mutex_lock(&acpi_ids_mutex);
+ (void)upload_pm_data(pr_backup);
+ mutex_unlock(&acpi_ids_mutex);
+ }
+ }
+ kfree(acpi_id_present);
+ acpi_id_present = NULL;
+}
+
+static int cpufreq_governor_xen(struct cpufreq_policy *policy,
+ unsigned int event)
+{
+ struct acpi_processor *_pr;
+
+ switch (event) {
+ case CPUFREQ_GOV_START:
+ case CPUFREQ_GOV_LIMITS:
+ /* Set it to max and let the hypervisor take over */
+ __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
+
+ _pr = per_cpu(processors, policy->cpu /* APIC ID */);
+ if (!_pr)
+ break;
+
+ mutex_lock(&acpi_ids_mutex);
+ if (!pr_backup) {
+ pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
+ memcpy(pr_backup, _pr, sizeof(struct acpi_processor));
+
+ INIT_DELAYED_WORK_DEFERRABLE(&work, do_check_acpi_id_timer);
+ schedule_delayed_work(&work, DELAY_TIMER);
+ }
+ (void)upload_pm_data(_pr);
+ mutex_unlock(&acpi_ids_mutex);
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+static struct cpufreq_governor cpufreq_gov_xen = {
+ .name = "xen",
+ .governor = cpufreq_governor_xen,
+ .owner = THIS_MODULE,
+};
+static int __init check_prereq(void)
+{
+ struct cpuinfo_x86 *c = &cpu_data(0);
+
+ if (!xen_initial_domain())
+ return -ENODEV;
+
+ if (!acpi_gbl_FADT.smi_command)
+ return -ENODEV;
+
+ if (c->x86_vendor == X86_VENDOR_INTEL) {
+ if (!cpu_has(c, X86_FEATURE_EST))
+ return -ENODEV;
+
+ return 0;
+ }
+ if (c->x86_vendor == X86_VENDOR_AMD) {
+ u32 hi = 0, lo = 0;
+ /* Copied from powernow-k8.h, can't include ../cpufreq/powernow
+ * as we get compile warnings for the static functions.
+ */
+#define MSR_PSTATE_CUR_LIMIT 0xc0010061 /* pstate current limit MSR */
+ rdmsr(MSR_PSTATE_CUR_LIMIT, lo, hi);
+
+ /* If the MSR cannot provide the data, the powernow-k8
+ * won't process the data properly either.
+ */
+ if (hi || lo)
+ return 0;
+ }
+ return -ENODEV;
+}
+
+static int __init xen_processor_passthru_init(void)
+{
+ int rc = check_prereq();
+
+ if (rc)
+ return rc;
+
+ acpi_ids_done = kcalloc(MAX_ACPI_BITS, sizeof(unsigned long), GFP_KERNEL);
+ if (!acpi_ids_done)
+ return -ENOMEM;
+ memset(acpi_ids_done, 0, MAX_ACPI_BITS * sizeof(unsigned long));
+
+ return cpufreq_register_governor(&cpufreq_gov_xen);
+}
+static void __exit xen_processor_passthru_exit(void)
+{
+ cpufreq_unregister_governor(&cpufreq_gov_xen);
+ cancel_delayed_work_sync(&work);
+ kfree(acpi_ids_done);
+ kfree(pr_backup);
+}
+
+MODULE_AUTHOR("Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>");
+MODULE_DESCRIPTION("CPUfreq policy governor 'xen' which uploads PM data to Xen hypervisor");
+MODULE_LICENSE("GPL");
+
+late_initcall(xen_processor_passthru_init);
+module_exit(xen_processor_passthru_exit);
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