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* Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
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* Alexander Graf <agraf@suse.de>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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#include <linux/kvm_host.h>
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#include <linux/init.h>
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#include <linux/export.h>
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#include <linux/kvm_para.h>
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#include <linux/slab.h>
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#include <asm/sections.h>
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#include <asm/cacheflush.h>
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#include <asm/disassemble.h>
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#define KVM_MAGIC_PAGE (-4096L)
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#define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)
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#define KVM_INST_LWZ 0x80000000
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#define KVM_INST_STW 0x90000000
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#define KVM_INST_LD 0xe8000000
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#define KVM_INST_STD 0xf8000000
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#define KVM_INST_NOP 0x60000000
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#define KVM_INST_B 0x48000000
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#define KVM_INST_B_MASK 0x03ffffff
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#define KVM_INST_B_MAX 0x01ffffff
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#define KVM_MASK_RT 0x03e00000
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#define KVM_RT_30 0x03c00000
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#define KVM_MASK_RB 0x0000f800
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#define KVM_INST_MFMSR 0x7c0000a6
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#define KVM_INST_MFSPR_SPRG0 0x7c1042a6
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#define KVM_INST_MFSPR_SPRG1 0x7c1142a6
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#define KVM_INST_MFSPR_SPRG2 0x7c1242a6
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#define KVM_INST_MFSPR_SPRG3 0x7c1342a6
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#define KVM_INST_MFSPR_SRR0 0x7c1a02a6
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#define KVM_INST_MFSPR_SRR1 0x7c1b02a6
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#define KVM_INST_MFSPR_DAR 0x7c1302a6
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#define KVM_INST_MFSPR_DSISR 0x7c1202a6
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#define KVM_INST_MTSPR_SPRG0 0x7c1043a6
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#define KVM_INST_MTSPR_SPRG1 0x7c1143a6
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#define KVM_INST_MTSPR_SPRG2 0x7c1243a6
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#define KVM_INST_MTSPR_SPRG3 0x7c1343a6
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#define KVM_INST_MTSPR_SRR0 0x7c1a03a6
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#define KVM_INST_MTSPR_SRR1 0x7c1b03a6
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#define KVM_INST_MTSPR_DAR 0x7c1303a6
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#define KVM_INST_MTSPR_DSISR 0x7c1203a6
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#define KVM_INST_TLBSYNC 0x7c00046c
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#define KVM_INST_MTMSRD_L0 0x7c000164
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#define KVM_INST_MTMSRD_L1 0x7c010164
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#define KVM_INST_MTMSR 0x7c000124
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#define KVM_INST_WRTEEI_0 0x7c000146
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#define KVM_INST_WRTEEI_1 0x7c008146
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#define KVM_INST_MTSRIN 0x7c0001e4
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static bool kvm_patching_worked = true;
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static char kvm_tmp[1024 * 1024];
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static int kvm_tmp_index;
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static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
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flush_icache_range((ulong)inst, (ulong)inst + 4);
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static void kvm_patch_ins_ll(u32 *inst, long addr, u32 rt)
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kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
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kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000fffc));
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static void kvm_patch_ins_ld(u32 *inst, long addr, u32 rt)
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kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
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kvm_patch_ins(inst, KVM_INST_LWZ | rt | ((addr + 4) & 0x0000fffc));
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static void kvm_patch_ins_lwz(u32 *inst, long addr, u32 rt)
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kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000ffff));
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static void kvm_patch_ins_std(u32 *inst, long addr, u32 rt)
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kvm_patch_ins(inst, KVM_INST_STD | rt | (addr & 0x0000fffc));
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kvm_patch_ins(inst, KVM_INST_STW | rt | ((addr + 4) & 0x0000fffc));
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static void kvm_patch_ins_stw(u32 *inst, long addr, u32 rt)
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kvm_patch_ins(inst, KVM_INST_STW | rt | (addr & 0x0000fffc));
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static void kvm_patch_ins_nop(u32 *inst)
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kvm_patch_ins(inst, KVM_INST_NOP);
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static void kvm_patch_ins_b(u32 *inst, int addr)
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#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC_BOOK3S)
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/* On relocatable kernels interrupts handlers and our code
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can be in different regions, so we don't patch them */
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if ((ulong)inst < (ulong)&__end_interrupts)
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kvm_patch_ins(inst, KVM_INST_B | (addr & KVM_INST_B_MASK));
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static u32 *kvm_alloc(int len)
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if ((kvm_tmp_index + len) > ARRAY_SIZE(kvm_tmp)) {
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printk(KERN_ERR "KVM: No more space (%d + %d)\n",
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kvm_patching_worked = false;
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p = (void*)&kvm_tmp[kvm_tmp_index];
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kvm_tmp_index += len;
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extern u32 kvm_emulate_mtmsrd_branch_offs;
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extern u32 kvm_emulate_mtmsrd_reg_offs;
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extern u32 kvm_emulate_mtmsrd_orig_ins_offs;
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extern u32 kvm_emulate_mtmsrd_len;
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extern u32 kvm_emulate_mtmsrd[];
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static void kvm_patch_ins_mtmsrd(u32 *inst, u32 rt)
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p = kvm_alloc(kvm_emulate_mtmsrd_len * 4);
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/* Find out where we are and put everything there */
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distance_start = (ulong)p - (ulong)inst;
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next_inst = ((ulong)inst + 4);
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distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsrd_branch_offs];
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/* Make sure we only write valid b instructions */
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if (distance_start > KVM_INST_B_MAX) {
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kvm_patching_worked = false;
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/* Modify the chunk to fit the invocation */
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memcpy(p, kvm_emulate_mtmsrd, kvm_emulate_mtmsrd_len * 4);
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p[kvm_emulate_mtmsrd_branch_offs] |= distance_end & KVM_INST_B_MASK;
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switch (get_rt(rt)) {
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kvm_patch_ins_ll(&p[kvm_emulate_mtmsrd_reg_offs],
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magic_var(scratch2), KVM_RT_30);
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kvm_patch_ins_ll(&p[kvm_emulate_mtmsrd_reg_offs],
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magic_var(scratch1), KVM_RT_30);
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p[kvm_emulate_mtmsrd_reg_offs] |= rt;
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p[kvm_emulate_mtmsrd_orig_ins_offs] = *inst;
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flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsrd_len * 4);
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/* Patch the invocation */
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kvm_patch_ins_b(inst, distance_start);
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extern u32 kvm_emulate_mtmsr_branch_offs;
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extern u32 kvm_emulate_mtmsr_reg1_offs;
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extern u32 kvm_emulate_mtmsr_reg2_offs;
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extern u32 kvm_emulate_mtmsr_orig_ins_offs;
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extern u32 kvm_emulate_mtmsr_len;
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extern u32 kvm_emulate_mtmsr[];
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static void kvm_patch_ins_mtmsr(u32 *inst, u32 rt)
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p = kvm_alloc(kvm_emulate_mtmsr_len * 4);
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/* Find out where we are and put everything there */
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distance_start = (ulong)p - (ulong)inst;
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next_inst = ((ulong)inst + 4);
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distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsr_branch_offs];
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/* Make sure we only write valid b instructions */
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if (distance_start > KVM_INST_B_MAX) {
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kvm_patching_worked = false;
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/* Modify the chunk to fit the invocation */
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memcpy(p, kvm_emulate_mtmsr, kvm_emulate_mtmsr_len * 4);
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p[kvm_emulate_mtmsr_branch_offs] |= distance_end & KVM_INST_B_MASK;
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/* Make clobbered registers work too */
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switch (get_rt(rt)) {
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kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
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magic_var(scratch2), KVM_RT_30);
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kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
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magic_var(scratch2), KVM_RT_30);
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kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
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magic_var(scratch1), KVM_RT_30);
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kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
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magic_var(scratch1), KVM_RT_30);
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p[kvm_emulate_mtmsr_reg1_offs] |= rt;
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p[kvm_emulate_mtmsr_reg2_offs] |= rt;
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p[kvm_emulate_mtmsr_orig_ins_offs] = *inst;
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flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsr_len * 4);
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/* Patch the invocation */
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kvm_patch_ins_b(inst, distance_start);
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extern u32 kvm_emulate_wrteei_branch_offs;
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extern u32 kvm_emulate_wrteei_ee_offs;
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extern u32 kvm_emulate_wrteei_len;
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extern u32 kvm_emulate_wrteei[];
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static void kvm_patch_ins_wrteei(u32 *inst)
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p = kvm_alloc(kvm_emulate_wrteei_len * 4);
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/* Find out where we are and put everything there */
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distance_start = (ulong)p - (ulong)inst;
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next_inst = ((ulong)inst + 4);
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distance_end = next_inst - (ulong)&p[kvm_emulate_wrteei_branch_offs];
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/* Make sure we only write valid b instructions */
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if (distance_start > KVM_INST_B_MAX) {
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kvm_patching_worked = false;
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/* Modify the chunk to fit the invocation */
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memcpy(p, kvm_emulate_wrteei, kvm_emulate_wrteei_len * 4);
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p[kvm_emulate_wrteei_branch_offs] |= distance_end & KVM_INST_B_MASK;
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p[kvm_emulate_wrteei_ee_offs] |= (*inst & MSR_EE);
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flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrteei_len * 4);
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/* Patch the invocation */
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kvm_patch_ins_b(inst, distance_start);
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#ifdef CONFIG_PPC_BOOK3S_32
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extern u32 kvm_emulate_mtsrin_branch_offs;
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extern u32 kvm_emulate_mtsrin_reg1_offs;
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extern u32 kvm_emulate_mtsrin_reg2_offs;
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extern u32 kvm_emulate_mtsrin_orig_ins_offs;
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extern u32 kvm_emulate_mtsrin_len;
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extern u32 kvm_emulate_mtsrin[];
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static void kvm_patch_ins_mtsrin(u32 *inst, u32 rt, u32 rb)
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p = kvm_alloc(kvm_emulate_mtsrin_len * 4);
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/* Find out where we are and put everything there */
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distance_start = (ulong)p - (ulong)inst;
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next_inst = ((ulong)inst + 4);
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distance_end = next_inst - (ulong)&p[kvm_emulate_mtsrin_branch_offs];
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/* Make sure we only write valid b instructions */
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if (distance_start > KVM_INST_B_MAX) {
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kvm_patching_worked = false;
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/* Modify the chunk to fit the invocation */
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memcpy(p, kvm_emulate_mtsrin, kvm_emulate_mtsrin_len * 4);
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p[kvm_emulate_mtsrin_branch_offs] |= distance_end & KVM_INST_B_MASK;
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p[kvm_emulate_mtsrin_reg1_offs] |= (rb << 10);
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p[kvm_emulate_mtsrin_reg2_offs] |= rt;
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p[kvm_emulate_mtsrin_orig_ins_offs] = *inst;
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flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtsrin_len * 4);
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/* Patch the invocation */
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kvm_patch_ins_b(inst, distance_start);
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static void kvm_map_magic_page(void *data)
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u32 *features = data;
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in[0] = KVM_MAGIC_PAGE;
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in[1] = KVM_MAGIC_PAGE;
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kvm_hypercall(in, out, HC_VENDOR_KVM | KVM_HC_PPC_MAP_MAGIC_PAGE);
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static void kvm_check_ins(u32 *inst, u32 features)
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u32 inst_no_rt = _inst & ~KVM_MASK_RT;
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u32 inst_rt = _inst & KVM_MASK_RT;
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switch (inst_no_rt) {
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kvm_patch_ins_ld(inst, magic_var(msr), inst_rt);
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case KVM_INST_MFSPR_SPRG0:
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kvm_patch_ins_ld(inst, magic_var(sprg0), inst_rt);
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case KVM_INST_MFSPR_SPRG1:
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kvm_patch_ins_ld(inst, magic_var(sprg1), inst_rt);
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case KVM_INST_MFSPR_SPRG2:
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kvm_patch_ins_ld(inst, magic_var(sprg2), inst_rt);
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case KVM_INST_MFSPR_SPRG3:
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kvm_patch_ins_ld(inst, magic_var(sprg3), inst_rt);
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case KVM_INST_MFSPR_SRR0:
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kvm_patch_ins_ld(inst, magic_var(srr0), inst_rt);
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case KVM_INST_MFSPR_SRR1:
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kvm_patch_ins_ld(inst, magic_var(srr1), inst_rt);
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case KVM_INST_MFSPR_DAR:
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kvm_patch_ins_ld(inst, magic_var(dar), inst_rt);
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case KVM_INST_MFSPR_DSISR:
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kvm_patch_ins_lwz(inst, magic_var(dsisr), inst_rt);
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case KVM_INST_MTSPR_SPRG0:
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kvm_patch_ins_std(inst, magic_var(sprg0), inst_rt);
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case KVM_INST_MTSPR_SPRG1:
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kvm_patch_ins_std(inst, magic_var(sprg1), inst_rt);
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case KVM_INST_MTSPR_SPRG2:
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kvm_patch_ins_std(inst, magic_var(sprg2), inst_rt);
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case KVM_INST_MTSPR_SPRG3:
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kvm_patch_ins_std(inst, magic_var(sprg3), inst_rt);
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case KVM_INST_MTSPR_SRR0:
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kvm_patch_ins_std(inst, magic_var(srr0), inst_rt);
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case KVM_INST_MTSPR_SRR1:
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kvm_patch_ins_std(inst, magic_var(srr1), inst_rt);
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case KVM_INST_MTSPR_DAR:
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kvm_patch_ins_std(inst, magic_var(dar), inst_rt);
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case KVM_INST_MTSPR_DSISR:
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kvm_patch_ins_stw(inst, magic_var(dsisr), inst_rt);
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case KVM_INST_TLBSYNC:
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kvm_patch_ins_nop(inst);
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case KVM_INST_MTMSRD_L1:
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kvm_patch_ins_mtmsrd(inst, inst_rt);
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case KVM_INST_MTMSRD_L0:
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kvm_patch_ins_mtmsr(inst, inst_rt);
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switch (inst_no_rt & ~KVM_MASK_RB) {
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#ifdef CONFIG_PPC_BOOK3S_32
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case KVM_INST_MTSRIN:
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if (features & KVM_MAGIC_FEAT_SR) {
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u32 inst_rb = _inst & KVM_MASK_RB;
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kvm_patch_ins_mtsrin(inst, inst_rt, inst_rb);
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case KVM_INST_WRTEEI_0:
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case KVM_INST_WRTEEI_1:
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kvm_patch_ins_wrteei(inst);
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static void kvm_use_magic_page(void)
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/* Tell the host to map the magic page to -4096 on all CPUs */
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on_each_cpu(kvm_map_magic_page, &features, 1);
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/* Quick self-test to see if the mapping works */
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if (__get_user(tmp, (u32*)KVM_MAGIC_PAGE)) {
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kvm_patching_worked = false;
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/* Now loop through all code and find instructions */
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start = (void*)_stext;
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for (p = start; p < end; p++)
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kvm_check_ins(p, features);
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printk(KERN_INFO "KVM: Live patching for a fast VM %s\n",
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kvm_patching_worked ? "worked" : "failed");
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unsigned long kvm_hypercall(unsigned long *in,
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unsigned long register r0 asm("r0");
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unsigned long register r3 asm("r3") = in[0];
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unsigned long register r4 asm("r4") = in[1];
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unsigned long register r5 asm("r5") = in[2];
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unsigned long register r6 asm("r6") = in[3];
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unsigned long register r7 asm("r7") = in[4];
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unsigned long register r8 asm("r8") = in[5];
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unsigned long register r9 asm("r9") = in[6];
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unsigned long register r10 asm("r10") = in[7];
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unsigned long register r11 asm("r11") = nr;
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unsigned long register r12 asm("r12");
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asm volatile("bl kvm_hypercall_start"
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: "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6),
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"=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11),
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: "r"(r3), "r"(r4), "r"(r5), "r"(r6), "r"(r7), "r"(r8),
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"r"(r9), "r"(r10), "r"(r11)
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: "memory", "cc", "xer", "ctr", "lr");
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EXPORT_SYMBOL_GPL(kvm_hypercall);
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static int kvm_para_setup(void)
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extern u32 kvm_hypercall_start;
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struct device_node *hyper_node;
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hyper_node = of_find_node_by_path("/hypervisor");
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insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len);
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for (i = 0; i < (len / 4); i++)
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kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]);
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static __init void kvm_free_tmp(void)
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unsigned long start, end;
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start = (ulong)&kvm_tmp[kvm_tmp_index + (PAGE_SIZE - 1)] & PAGE_MASK;
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end = (ulong)&kvm_tmp[ARRAY_SIZE(kvm_tmp)] & PAGE_MASK;
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/* Free the tmp space we don't need */
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for (; start < end; start += PAGE_SIZE) {
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ClearPageReserved(virt_to_page(start));
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init_page_count(virt_to_page(start));
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static int __init kvm_guest_init(void)
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if (!kvm_para_available())
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if (kvm_para_setup())
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if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
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kvm_use_magic_page();
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#ifdef CONFIG_PPC_BOOK3S_64
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postcore_initcall(kvm_guest_init);