kvm.c

/*
 * Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
 * Copyright 2010-2011 Freescale Semiconductor, Inc.
 *
 * Authors:
 *     Alexander Graf <agraf@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/kvm_host.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/kvm_para.h>
#include <linux/slab.h>
#include <linux/of.h>

#include <asm/reg.h>
#include <asm/sections.h>
#include <asm/cacheflush.h>
#include <asm/disassemble.h>
#include <asm/ppc-opcode.h>
#include <asm/epapr_hcalls.h>

#define KVM_MAGIC_PAGE		(-4096L)
#define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)

#define KVM_INST_LWZ		0x80000000
#define KVM_INST_STW		0x90000000
#define KVM_INST_LD		0xe8000000
#define KVM_INST_STD		0xf8000000
#define KVM_INST_NOP		0x60000000
#define KVM_INST_B		0x48000000
#define KVM_INST_B_MASK		0x03ffffff
#define KVM_INST_B_MAX		0x01ffffff
#define KVM_INST_LI		0x38000000

#define KVM_MASK_RT		0x03e00000
#define KVM_RT_30		0x03c00000
#define KVM_MASK_RB		0x0000f800
#define KVM_INST_MFMSR		0x7c0000a6

#define SPR_FROM		0
#define SPR_TO			0x100

#define KVM_INST_SPR(sprn, moveto) (0x7c0002a6 | \
				    (((sprn) & 0x1f) << 16) | \
				    (((sprn) & 0x3e0) << 6) | \
				    (moveto))

#define KVM_INST_MFSPR(sprn)	KVM_INST_SPR(sprn, SPR_FROM)
#define KVM_INST_MTSPR(sprn)	KVM_INST_SPR(sprn, SPR_TO)

#define KVM_INST_TLBSYNC	0x7c00046c
#define KVM_INST_MTMSRD_L0	0x7c000164
#define KVM_INST_MTMSRD_L1	0x7c010164
#define KVM_INST_MTMSR		0x7c000124

#define KVM_INST_WRTEE		0x7c000106
#define KVM_INST_WRTEEI_0	0x7c000146
#define KVM_INST_WRTEEI_1	0x7c008146

#define KVM_INST_MTSRIN		0x7c0001e4

static bool kvm_patching_worked = true;
char kvm_tmp[1024 * 1024];
static int kvm_tmp_index;

static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
{
	*inst = new_inst;
	flush_icache_range((ulong)inst, (ulong)inst + 4);
}

static void kvm_patch_ins_ll(u32 *inst, long addr, u32 rt)
{
#ifdef CONFIG_64BIT
	kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
#else
	kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000fffc));
#endif
}

static void kvm_patch_ins_ld(u32 *inst, long addr, u32 rt)
{
#ifdef CONFIG_64BIT
	kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
#else
	kvm_patch_ins(inst, KVM_INST_LWZ | rt | ((addr + 4) & 0x0000fffc));
#endif
}

static void kvm_patch_ins_lwz(u32 *inst, long addr, u32 rt)
{
	kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000ffff));
}

static void kvm_patch_ins_std(u32 *inst, long addr, u32 rt)
{
#ifdef CONFIG_64BIT
	kvm_patch_ins(inst, KVM_INST_STD | rt | (addr & 0x0000fffc));
#else
	kvm_patch_ins(inst, KVM_INST_STW | rt | ((addr + 4) & 0x0000fffc));
#endif
}

static void kvm_patch_ins_stw(u32 *inst, long addr, u32 rt)
{
	kvm_patch_ins(inst, KVM_INST_STW | rt | (addr & 0x0000fffc));
}

static void kvm_patch_ins_nop(u32 *inst)
{
	kvm_patch_ins(inst, KVM_INST_NOP);
}

static void kvm_patch_ins_b(u32 *inst, int addr)
{
#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC_BOOK3S)
	/* On relocatable kernels interrupts handlers and our code
	   can be in different regions, so we don't patch them */

	if ((ulong)inst < (ulong)&__end_interrupts)
		return;
#endif

	kvm_patch_ins(inst, KVM_INST_B | (addr & KVM_INST_B_MASK));
}

static u32 *kvm_alloc(int len)
{
	u32 *p;

	if ((kvm_tmp_index + len) > ARRAY_SIZE(kvm_tmp)) {
		printk(KERN_ERR "KVM: No more space (%d + %d)\n",
				kvm_tmp_index, len);
		kvm_patching_worked = false;
		return NULL;
	}

	p = (void*)&kvm_tmp[kvm_tmp_index];
	kvm_tmp_index += len;

	return p;
}

extern u32 kvm_emulate_mtmsrd_branch_offs;
extern u32 kvm_emulate_mtmsrd_reg_offs;
extern u32 kvm_emulate_mtmsrd_orig_ins_offs;
extern u32 kvm_emulate_mtmsrd_len;
extern u32 kvm_emulate_mtmsrd[];

static void kvm_patch_ins_mtmsrd(u32 *inst, u32 rt)
{
	u32 *p;
	int distance_start;
	int distance_end;
	ulong next_inst;

	p = kvm_alloc(kvm_emulate_mtmsrd_len * 4);
	if (!p)
		return;

	/* Find out where we are and put everything there */
	distance_start = (ulong)p - (ulong)inst;
	next_inst = ((ulong)inst + 4);
	distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsrd_branch_offs];

	/* Make sure we only write valid b instructions */
	if (distance_start > KVM_INST_B_MAX) {
		kvm_patching_worked = false;
		return;
	}

	/* Modify the chunk to fit the invocation */
	memcpy(p, kvm_emulate_mtmsrd, kvm_emulate_mtmsrd_len * 4);
	p[kvm_emulate_mtmsrd_branch_offs] |= distance_end & KVM_INST_B_MASK;
	switch (get_rt(rt)) {
	case 30:
		kvm_patch_ins_ll(&p[kvm_emulate_mtmsrd_reg_offs],
				 magic_var(scratch2), KVM_RT_30);
		break;
	case 31:
		kvm_patch_ins_ll(&p[kvm_emulate_mtmsrd_reg_offs],
				 magic_var(scratch1), KVM_RT_30);
		break;
	default:
		p[kvm_emulate_mtmsrd_reg_offs] |= rt;
		break;
	}

	p[kvm_emulate_mtmsrd_orig_ins_offs] = *inst;
	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsrd_len * 4);

	/* Patch the invocation */
	kvm_patch_ins_b(inst, distance_start);
}

extern u32 kvm_emulate_mtmsr_branch_offs;
extern u32 kvm_emulate_mtmsr_reg1_offs;
extern u32 kvm_emulate_mtmsr_reg2_offs;
extern u32 kvm_emulate_mtmsr_orig_ins_offs;
extern u32 kvm_emulate_mtmsr_len;
extern u32 kvm_emulate_mtmsr[];

static void kvm_patch_ins_mtmsr(u32 *inst, u32 rt)
{
	u32 *p;
	int distance_start;
	int distance_end;
	ulong next_inst;

	p = kvm_alloc(kvm_emulate_mtmsr_len * 4);
	if (!p)
		return;

	/* Find out where we are and put everything there */
	distance_start = (ulong)p - (ulong)inst;
	next_inst = ((ulong)inst + 4);
	distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsr_branch_offs];

	/* Make sure we only write valid b instructions */
	if (distance_start > KVM_INST_B_MAX) {
		kvm_patching_worked = false;
		return;
	}

	/* Modify the chunk to fit the invocation */
	memcpy(p, kvm_emulate_mtmsr, kvm_emulate_mtmsr_len * 4);
	p[kvm_emulate_mtmsr_branch_offs] |= distance_end & KVM_INST_B_MASK;

	/* Make clobbered registers work too */
	switch (get_rt(rt)) {
	case 30:
		kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
				 magic_var(scratch2), KVM_RT_30);
		kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
				 magic_var(scratch2), KVM_RT_30);
		break;
	case 31:
		kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
				 magic_var(scratch1), KVM_RT_30);
		kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
				 magic_var(scratch1), KVM_RT_30);
		break;
	default:
		p[kvm_emulate_mtmsr_reg1_offs] |= rt;
		p[kvm_emulate_mtmsr_reg2_offs] |= rt;
		break;
	}

	p[kvm_emulate_mtmsr_orig_ins_offs] = *inst;
	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsr_len * 4);

	/* Patch the invocation */
	kvm_patch_ins_b(inst, distance_start);
}

#ifdef CONFIG_BOOKE

extern u32 kvm_emulate_wrtee_branch_offs;
extern u32 kvm_emulate_wrtee_reg_offs;
extern u32 kvm_emulate_wrtee_orig_ins_offs;
extern u32 kvm_emulate_wrtee_len;
extern u32 kvm_emulate_wrtee[];

static void kvm_patch_ins_wrtee(u32 *inst, u32 rt, int imm_one)
{
	u32 *p;
	int distance_start;
	int distance_end;
	ulong next_inst;

	p = kvm_alloc(kvm_emulate_wrtee_len * 4);
	if (!p)
		return;

	/* Find out where we are and put everything there */
	distance_start = (ulong)p - (ulong)inst;
	next_inst = ((ulong)inst + 4);
	distance_end = next_inst - (ulong)&p[kvm_emulate_wrtee_branch_offs];

	/* Make sure we only write valid b instructions */
	if (distance_start > KVM_INST_B_MAX) {
		kvm_patching_worked = false;
		return;
	}

	/* Modify the chunk to fit the invocation */
	memcpy(p, kvm_emulate_wrtee, kvm_emulate_wrtee_len * 4);
	p[kvm_emulate_wrtee_branch_offs] |= distance_end & KVM_INST_B_MASK;

	if (imm_one) {
		p[kvm_emulate_wrtee_reg_offs] =
			KVM_INST_LI | __PPC_RT(R30) | MSR_EE;
	} else {
		/* Make clobbered registers work too */
		switch (get_rt(rt)) {
		case 30:
			kvm_patch_ins_ll(&p[kvm_emulate_wrtee_reg_offs],
					 magic_var(scratch2), KVM_RT_30);
			break;
		case 31:
			kvm_patch_ins_ll(&p[kvm_emulate_wrtee_reg_offs],
					 magic_var(scratch1), KVM_RT_30);
			break;
		default:
			p[kvm_emulate_wrtee_reg_offs] |= rt;
			break;
		}
	}

	p[kvm_emulate_wrtee_orig_ins_offs] = *inst;
	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrtee_len * 4);

	/* Patch the invocation */
	kvm_patch_ins_b(inst, distance_start);
}

extern u32 kvm_emulate_wrteei_0_branch_offs;
extern u32 kvm_emulate_wrteei_0_len;
extern u32 kvm_emulate_wrteei_0[];

static void kvm_patch_ins_wrteei_0(u32 *inst)
{
	u32 *p;
	int distance_start;
	int distance_end;
	ulong next_inst;

	p = kvm_alloc(kvm_emulate_wrteei_0_len * 4);
	if (!p)
		return;

	/* Find out where we are and put everything there */
	distance_start = (ulong)p - (ulong)inst;
	next_inst = ((ulong)inst + 4);
	distance_end = next_inst - (ulong)&p[kvm_emulate_wrteei_0_branch_offs];

	/* Make sure we only write valid b instructions */
	if (distance_start > KVM_INST_B_MAX) {
		kvm_patching_worked = false;
		return;
	}

	memcpy(p, kvm_emulate_wrteei_0, kvm_emulate_wrteei_0_len * 4);
	p[kvm_emulate_wrteei_0_branch_offs] |= distance_end & KVM_INST_B_MASK;
	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrteei_0_len * 4);

	/* Patch the invocation */
	kvm_patch_ins_b(inst, distance_start);
}

#endif

#ifdef CONFIG_PPC_BOOK3S_32

extern u32 kvm_emulate_mtsrin_branch_offs;
extern u32 kvm_emulate_mtsrin_reg1_offs;
extern u32 kvm_emulate_mtsrin_reg2_offs;
extern u32 kvm_emulate_mtsrin_orig_ins_offs;
extern u32 kvm_emulate_mtsrin_len;
extern u32 kvm_emulate_mtsrin[];

static void kvm_patch_ins_mtsrin(u32 *inst, u32 rt, u32 rb)
{
	u32 *p;
	int distance_start;
	int distance_end;
	ulong next_inst;

	p = kvm_alloc(kvm_emulate_mtsrin_len * 4);
	if (!p)
		return;

	/* Find out where we are and put everything there */
	distance_start = (ulong)p - (ulong)inst;
	next_inst = ((ulong)inst + 4);
	distance_end = next_inst - (ulong)&p[kvm_emulate_mtsrin_branch_offs];

	/* Make sure we only write valid b instructions */
	if (distance_start > KVM_INST_B_MAX) {
		kvm_patching_worked = false;
		return;
	}

	/* Modify the chunk to fit the invocation */
	memcpy(p, kvm_emulate_mtsrin, kvm_emulate_mtsrin_len * 4);
	p[kvm_emulate_mtsrin_branch_offs] |= distance_end & KVM_INST_B_MASK;
	p[kvm_emulate_mtsrin_reg1_offs] |= (rb << 10);
	p[kvm_emulate_mtsrin_reg2_offs] |= rt;
	p[kvm_emulate_mtsrin_orig_ins_offs] = *inst;
	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtsrin_len * 4);

	/* Patch the invocation */
	kvm_patch_ins_b(inst, distance_start);
}

#endif

static void kvm_map_magic_page(void *data)
{
	u32 *features = data;

	ulong in[8] = {0};
	ulong out[8];

	in[0] = KVM_MAGIC_PAGE;
	in[1] = KVM_MAGIC_PAGE;

	epapr_hypercall(in, out, KVM_HCALL_TOKEN(KVM_HC_PPC_MAP_MAGIC_PAGE));

	*features = out[0];
}

static void kvm_check_ins(u32 *inst, u32 features)
{
	u32 _inst = *inst;
	u32 inst_no_rt = _inst & ~KVM_MASK_RT;
	u32 inst_rt = _inst & KVM_MASK_RT;

	switch (inst_no_rt) {
	/* Loads */
	case KVM_INST_MFMSR:
		kvm_patch_ins_ld(inst, magic_var(msr), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SPRG0):
		kvm_patch_ins_ld(inst, magic_var(sprg0), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SPRG1):
		kvm_patch_ins_ld(inst, magic_var(sprg1), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SPRG2):
		kvm_patch_ins_ld(inst, magic_var(sprg2), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SPRG3):
		kvm_patch_ins_ld(inst, magic_var(sprg3), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SRR0):
		kvm_patch_ins_ld(inst, magic_var(srr0), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SRR1):
		kvm_patch_ins_ld(inst, magic_var(srr1), inst_rt);
		break;
#ifdef CONFIG_BOOKE
	case KVM_INST_MFSPR(SPRN_DEAR):
#else
	case KVM_INST_MFSPR(SPRN_DAR):
#endif
		kvm_patch_ins_ld(inst, magic_var(dar), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_DSISR):
		kvm_patch_ins_lwz(inst, magic_var(dsisr), inst_rt);
		break;

#ifdef CONFIG_PPC_BOOK3E_MMU
	case KVM_INST_MFSPR(SPRN_MAS0):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(mas0), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_MAS1):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(mas1), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_MAS2):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_ld(inst, magic_var(mas2), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_MAS3):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(mas7_3) + 4, inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_MAS4):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(mas4), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_MAS6):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(mas6), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_MAS7):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(mas7_3), inst_rt);
		break;
#endif /* CONFIG_PPC_BOOK3E_MMU */

	case KVM_INST_MFSPR(SPRN_SPRG4):
#ifdef CONFIG_BOOKE
	case KVM_INST_MFSPR(SPRN_SPRG4R):
#endif
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_ld(inst, magic_var(sprg4), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SPRG5):
#ifdef CONFIG_BOOKE
	case KVM_INST_MFSPR(SPRN_SPRG5R):
#endif
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_ld(inst, magic_var(sprg5), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SPRG6):
#ifdef CONFIG_BOOKE
	case KVM_INST_MFSPR(SPRN_SPRG6R):
#endif
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_ld(inst, magic_var(sprg6), inst_rt);
		break;
	case KVM_INST_MFSPR(SPRN_SPRG7):
#ifdef CONFIG_BOOKE
	case KVM_INST_MFSPR(SPRN_SPRG7R):
#endif
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_ld(inst, magic_var(sprg7), inst_rt);
		break;

#ifdef CONFIG_BOOKE
	case KVM_INST_MFSPR(SPRN_ESR):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(esr), inst_rt);
		break;
#endif

	case KVM_INST_MFSPR(SPRN_PIR):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_lwz(inst, magic_var(pir), inst_rt);
		break;


	/* Stores */
	case KVM_INST_MTSPR(SPRN_SPRG0):
		kvm_patch_ins_std(inst, magic_var(sprg0), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SPRG1):
		kvm_patch_ins_std(inst, magic_var(sprg1), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SPRG2):
		kvm_patch_ins_std(inst, magic_var(sprg2), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SPRG3):
		kvm_patch_ins_std(inst, magic_var(sprg3), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SRR0):
		kvm_patch_ins_std(inst, magic_var(srr0), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SRR1):
		kvm_patch_ins_std(inst, magic_var(srr1), inst_rt);
		break;
#ifdef CONFIG_BOOKE
	case KVM_INST_MTSPR(SPRN_DEAR):
#else
	case KVM_INST_MTSPR(SPRN_DAR):
#endif
		kvm_patch_ins_std(inst, magic_var(dar), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_DSISR):
		kvm_patch_ins_stw(inst, magic_var(dsisr), inst_rt);
		break;
#ifdef CONFIG_PPC_BOOK3E_MMU
	case KVM_INST_MTSPR(SPRN_MAS0):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_stw(inst, magic_var(mas0), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_MAS1):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_stw(inst, magic_var(mas1), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_MAS2):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_std(inst, magic_var(mas2), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_MAS3):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_stw(inst, magic_var(mas7_3) + 4, inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_MAS4):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_stw(inst, magic_var(mas4), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_MAS6):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_stw(inst, magic_var(mas6), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_MAS7):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_stw(inst, magic_var(mas7_3), inst_rt);
		break;
#endif /* CONFIG_PPC_BOOK3E_MMU */

	case KVM_INST_MTSPR(SPRN_SPRG4):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_std(inst, magic_var(sprg4), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SPRG5):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_std(inst, magic_var(sprg5), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SPRG6):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_std(inst, magic_var(sprg6), inst_rt);
		break;
	case KVM_INST_MTSPR(SPRN_SPRG7):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_std(inst, magic_var(sprg7), inst_rt);
		break;

#ifdef CONFIG_BOOKE
	case KVM_INST_MTSPR(SPRN_ESR):
		if (features & KVM_MAGIC_FEAT_MAS0_TO_SPRG7)
			kvm_patch_ins_stw(inst, magic_var(esr), inst_rt);
		break;
#endif

	/* Nops */
	case KVM_INST_TLBSYNC:
		kvm_patch_ins_nop(inst);
		break;

	/* Rewrites */
	case KVM_INST_MTMSRD_L1:
		kvm_patch_ins_mtmsrd(inst, inst_rt);
		break;
	case KVM_INST_MTMSR:
	case KVM_INST_MTMSRD_L0:
		kvm_patch_ins_mtmsr(inst, inst_rt);
		break;
#ifdef CONFIG_BOOKE
	case KVM_INST_WRTEE:
		kvm_patch_ins_wrtee(inst, inst_rt, 0);
		break;
#endif
	}

	switch (inst_no_rt & ~KVM_MASK_RB) {
#ifdef CONFIG_PPC_BOOK3S_32
	case KVM_INST_MTSRIN:
		if (features & KVM_MAGIC_FEAT_SR) {
			u32 inst_rb = _inst & KVM_MASK_RB;
			kvm_patch_ins_mtsrin(inst, inst_rt, inst_rb);
		}
		break;
		break;
#endif
	}

	switch (_inst) {
#ifdef CONFIG_BOOKE
	case KVM_INST_WRTEEI_0:
		kvm_patch_ins_wrteei_0(inst);
		break;

	case KVM_INST_WRTEEI_1:
		kvm_patch_ins_wrtee(inst, 0, 1);
		break;
#endif
	}
}

extern u32 kvm_template_start[];
extern u32 kvm_template_end[];

static void kvm_use_magic_page(void)
{
	u32 *p;
	u32 *start, *end;
	u32 tmp;
	u32 features;

	/* Tell the host to map the magic page to -4096 on all CPUs */
	on_each_cpu(kvm_map_magic_page, &features, 1);

	/* Quick self-test to see if the mapping works */
	if (__get_user(tmp, (u32*)KVM_MAGIC_PAGE)) {
		kvm_patching_worked = false;
		return;
	}

	/* Now loop through all code and find instructions */
	start = (void*)_stext;
	end = (void*)_etext;

	/*
	 * Being interrupted in the middle of patching would
	 * be bad for SPRG4-7, which KVM can't keep in sync
	 * with emulated accesses because reads don't trap.
	 */
	local_irq_disable();

	for (p = start; p < end; p++) {
		/* Avoid patching the template code */
		if (p >= kvm_template_start && p < kvm_template_end) {
			p = kvm_template_end - 1;
			continue;
		}
		kvm_check_ins(p, features);
	}

	local_irq_enable();

	printk(KERN_INFO "KVM: Live patching for a fast VM %s\n",
			 kvm_patching_worked ? "worked" : "failed");
}

static __init void kvm_free_tmp(void)
{
	free_reserved_area(&kvm_tmp[kvm_tmp_index],
			   &kvm_tmp[ARRAY_SIZE(kvm_tmp)], -1, NULL);
}

static int __init kvm_guest_init(void)
{
	if (!kvm_para_available())
		goto free_tmp;

	if (!epapr_paravirt_enabled)
		goto free_tmp;

	if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
		kvm_use_magic_page();

#ifdef CONFIG_PPC_BOOK3S_64
	/* Enable napping */
	powersave_nap = 1;
#endif

free_tmp:
	kvm_free_tmp();

	return 0;
}

postcore_initcall(kvm_guest_init);