// SPDX-License-Identifier: GPL-2.0-only
/*
 * vMTRR implementation
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 * Copyright(C) 2015 Intel Corporation.
 *
 * Authors:
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Avi Kivity   <avi@qumranet.com>
 *   Marcelo Tosatti <mtosatti@redhat.com>
 *   Paolo Bonzini <pbonzini@redhat.com>
 *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kvm_host.h>
#include <asm/mtrr.h>

#include "cpuid.h"
#include "x86.h"

static u64 *find_mtrr(struct kvm_vcpu *vcpu, unsigned int msr)
{
        int index;

        switch (msr) {
        case MTRRphysBase_MSR(0) ... MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1):
                index = msr - MTRRphysBase_MSR(0);
                return &vcpu->arch.mtrr_state.var[index];
        case MSR_MTRRfix64K_00000:
                return &vcpu->arch.mtrr_state.fixed_64k;
        case MSR_MTRRfix16K_80000:
        case MSR_MTRRfix16K_A0000:
                index = msr - MSR_MTRRfix16K_80000;
                return &vcpu->arch.mtrr_state.fixed_16k[index];
        case MSR_MTRRfix4K_C0000:
        case MSR_MTRRfix4K_C8000:
        case MSR_MTRRfix4K_D0000:
        case MSR_MTRRfix4K_D8000:
        case MSR_MTRRfix4K_E0000:
        case MSR_MTRRfix4K_E8000:
        case MSR_MTRRfix4K_F0000:
        case MSR_MTRRfix4K_F8000:
                index = msr - MSR_MTRRfix4K_C0000;
                return &vcpu->arch.mtrr_state.fixed_4k[index];
        case MSR_MTRRdefType:
                return &vcpu->arch.mtrr_state.deftype;
        default:
                break;
        }
        return NULL;
}

static bool valid_mtrr_type(unsigned t)
{
        return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
}

static bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
        int i;
        u64 mask;

        if (msr == MSR_MTRRdefType) {
                if (data & ~0xcff)
                        return false;
                return valid_mtrr_type(data & 0xff);
        } else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) {
                for (i = 0; i < 8 ; i++)
                        if (!valid_mtrr_type((data >> (i * 8)) & 0xff))
                                return false;
                return true;
        }

        /* variable MTRRs */
        if (WARN_ON_ONCE(!(msr >= MTRRphysBase_MSR(0) &&
                           msr <= MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1))))
                return false;

        mask = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
        if ((msr & 1) == 0) {
                /* MTRR base */
                if (!valid_mtrr_type(data & 0xff))
                        return false;
                mask |= 0xf00;
        } else {
                /* MTRR mask */
                mask |= 0x7ff;
        }

        return (data & mask) == 0;
}

int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
        u64 *mtrr;

        mtrr = find_mtrr(vcpu, msr);
        if (!mtrr)
                return 1;

        if (!kvm_mtrr_valid(vcpu, msr, data))
                return 1;

        *mtrr = data;
        return 0;
}

int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
        u64 *mtrr;

        /* MSR_MTRRcap is a readonly MSR. */
        if (msr == MSR_MTRRcap) {
                /*
                 * SMRR = 0
                 * WC = 1
                 * FIX = 1
                 * VCNT = KVM_NR_VAR_MTRR
                 */
                *pdata = 0x500 | KVM_NR_VAR_MTRR;
                return 0;
        }

        mtrr = find_mtrr(vcpu, msr);
        if (!mtrr)
                return 1;

        *pdata = *mtrr;
        return 0;
}