zircon/kernel/arch/x86/msr.cc

// Copyright 2019 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#include <assert.h>
#include <debug.h>
#include <platform.h>
#include <stdio.h>
#include <string.h>
#include <trace.h>
#include <zircon/compiler.h>
#include <zircon/types.h>

#include <arch/mp.h>
#include <arch/ops.h>
#include <arch/x86.h>
#include <arch/x86/apic.h>
#include <arch/x86/descriptor.h>
#include <arch/x86/feature.h>
#include <arch/x86/interrupts.h>
#include <arch/x86/mp.h>
#include <dev/hw_rng.h>
#include <dev/interrupt.h>
#include <kernel/event.h>
#include <kernel/timer.h>

struct read_msr_context {
  uint32_t msr;
  uint64_t val;
};

static void read_msr_on_cpu_task(void* raw_context) {
  auto* const context = reinterpret_cast<struct read_msr_context*>(raw_context);
  context->val = read_msr(context->msr);
}

uint64_t read_msr_on_cpu(cpu_num_t cpu, uint32_t msr_id) {
  struct read_msr_context context = {};
  cpu_mask_t mask = {};

  if (!mp_is_cpu_online(cpu)) {
    return -1;
  }

  context.msr = msr_id;
  mask |= cpu_num_to_mask(cpu);
  mp_sync_exec(MP_IPI_TARGET_MASK, mask, read_msr_on_cpu_task, reinterpret_cast<void*>(&context));
  return context.val;
}

struct write_msr_context {
  uint32_t msr;
  uint64_t val;
};

static void write_msr_on_cpu_task(void* raw_context) {
  auto* const context = reinterpret_cast<struct write_msr_context*>(raw_context);
  write_msr(context->msr, context->val);
}

void write_msr_on_cpu(cpu_num_t cpu, uint32_t msr_id, uint64_t val) {
  struct write_msr_context context = {};
  cpu_mask_t mask = {};

  context.msr = msr_id;
  context.val = val;
  mask |= cpu_num_to_mask(cpu);
  mp_sync_exec(MP_IPI_TARGET_MASK, mask, write_msr_on_cpu_task, reinterpret_cast<void*>(&context));
}