/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 NetApp, Inc.
 * All rights reserved.
 *
 * 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 NETAPP, INC ``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 NETAPP, INC 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/types.h>

#include <machine/cpufunc.h>
#include <machine/vmm.h>
#include <machine/specialreg.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <vmmapi.h>

#include "debug.h"
#include "xmsr.h"

static int cpu_vendor_intel, cpu_vendor_amd, cpu_vendor_hygon;

int
emulate_wrmsr(struct vcpu *vcpu __unused, uint32_t num, uint64_t val __unused)
{

	if (cpu_vendor_intel) {
		switch (num) {
		case 0xd04:		/* Sandy Bridge uncore PMCs */
		case 0xc24:
			return (0);
		case MSR_BIOS_UPDT_TRIG:
			return (0);
		case MSR_BIOS_SIGN:
			return (0);
		default:
			break;
		}
	} else if (cpu_vendor_amd || cpu_vendor_hygon) {
		switch (num) {
		case MSR_HWCR:
			/*
			 * Ignore writes to hardware configuration MSR.
			 */
			return (0);

		case MSR_NB_CFG1:
		case MSR_LS_CFG:
		case MSR_IC_CFG:
			return (0);	/* Ignore writes */

		case MSR_PERFEVSEL0:
		case MSR_PERFEVSEL1:
		case MSR_PERFEVSEL2:
		case MSR_PERFEVSEL3:
			/* Ignore writes to the PerfEvtSel MSRs */
			return (0);

		case MSR_K7_PERFCTR0:
		case MSR_K7_PERFCTR1:
		case MSR_K7_PERFCTR2:
		case MSR_K7_PERFCTR3:
			/* Ignore writes to the PerfCtr MSRs */
			return (0);

		case MSR_P_STATE_CONTROL:
			/* Ignore write to change the P-state */
			return (0);

		default:
			break;
		}
	}
	return (-1);
}

int
emulate_rdmsr(struct vcpu *vcpu __unused, uint32_t num, uint64_t *val)
{
	int error = 0;

	if (cpu_vendor_intel) {
		switch (num) {
		case MSR_BIOS_SIGN:
		case MSR_IA32_PLATFORM_ID:
		case MSR_PKG_ENERGY_STATUS:
		case MSR_PP0_ENERGY_STATUS:
		case MSR_PP1_ENERGY_STATUS:
		case MSR_DRAM_ENERGY_STATUS:
		case MSR_MISC_FEATURE_ENABLES:
			*val = 0;
			break;
		case MSR_RAPL_POWER_UNIT:
			/*
			 * Use the default value documented in section
			 * "RAPL Interfaces" in Intel SDM vol3.
			 */
			*val = 0x000a1003;
			break;
		case MSR_IA32_FEATURE_CONTROL:
			/*
			 * Windows guests check this MSR.
			 * Set the lock bit to avoid writes
			 * to this MSR.
			 */
			*val = IA32_FEATURE_CONTROL_LOCK;
			break;
		default:
			error = -1;
			break;
		}
	} else if (cpu_vendor_amd || cpu_vendor_hygon) {
		switch (num) {
		case MSR_BIOS_SIGN:
			*val = 0;
			break;
		case MSR_HWCR:
			/*
			 * Bios and Kernel Developer's Guides for AMD Families
			 * 12H, 14H, 15H and 16H.
			 */
			*val = 0x01000010;	/* Reset value */
			*val |= 1 << 9;		/* MONITOR/MWAIT disable */
			break;

		case MSR_NB_CFG1:
		case MSR_LS_CFG:
		case MSR_IC_CFG:
			/*
			 * The reset value is processor family dependent so
			 * just return 0.
			 */
			*val = 0;
			break;

		case MSR_PERFEVSEL0:
		case MSR_PERFEVSEL1:
		case MSR_PERFEVSEL2:
		case MSR_PERFEVSEL3:
			/*
			 * PerfEvtSel MSRs are not properly virtualized so just
			 * return zero.
			 */
			*val = 0;
			break;

		case MSR_K7_PERFCTR0:
		case MSR_K7_PERFCTR1:
		case MSR_K7_PERFCTR2:
		case MSR_K7_PERFCTR3:
			/*
			 * PerfCtr MSRs are not properly virtualized so just
			 * return zero.
			 */
			*val = 0;
			break;

		case MSR_SMM_ADDR:
		case MSR_SMM_MASK:
			/*
			 * Return the reset value defined in the AMD Bios and
			 * Kernel Developer's Guide.
			 */
			*val = 0;
			break;

		case MSR_P_STATE_LIMIT:
		case MSR_P_STATE_CONTROL:
		case MSR_P_STATE_STATUS:
		case MSR_P_STATE_CONFIG(0):	/* P0 configuration */
			*val = 0;
			break;

		/*
		 * OpenBSD guests test bit 0 of this MSR to detect if the
		 * workaround for erratum 721 is already applied.
		 * https://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf
		 */
		case 0xC0011029:
			*val = 1;
			break;

		default:
			error = -1;
			break;
		}
	} else {
		error = -1;
	}
	return (error);
}

int
init_msr(void)
{
	int error;
	u_int regs[4];
	char cpu_vendor[13];

	do_cpuid(0, regs);
	((u_int *)&cpu_vendor)[0] = regs[1];
	((u_int *)&cpu_vendor)[1] = regs[3];
	((u_int *)&cpu_vendor)[2] = regs[2];
	cpu_vendor[12] = '\0';

	error = 0;
	if (strcmp(cpu_vendor, "AuthenticAMD") == 0) {
		cpu_vendor_amd = 1;
	} else if (strcmp(cpu_vendor, "HygonGenuine") == 0) {
		cpu_vendor_hygon = 1;
	} else if (strcmp(cpu_vendor, "GenuineIntel") == 0) {
		cpu_vendor_intel = 1;
	} else {
		EPRINTLN("Unknown cpu vendor \"%s\"", cpu_vendor);
		error = ENOENT;
	}
	return (error);
}