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linux-stable/arch/powerpc/kernel/kvm.c
Anton Blanchard d715e433b7 powerpc: Copy down exception vectors after feature fixups 
kdump fails because we try to execute an HV only instruction. Feature
fixups are being applied after we copy the exception vectors down to 0
so they miss out on any updates.

We have always had this issue but it only became critical in v3.0
when we added CFAR support (breaks POWER5) and v3.1 when we added
POWERNV (breaks everyone).

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> [v3.0+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-16 14:47:54 +11:00

596 lines
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/*
* Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
*
* 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>
#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_MASK_RT 0x03e00000
#define KVM_RT_30 0x03c00000
#define KVM_MASK_RB 0x0000f800
#define KVM_INST_MFMSR 0x7c0000a6
#define KVM_INST_MFSPR_SPRG0 0x7c1042a6
#define KVM_INST_MFSPR_SPRG1 0x7c1142a6
#define KVM_INST_MFSPR_SPRG2 0x7c1242a6
#define KVM_INST_MFSPR_SPRG3 0x7c1342a6
#define KVM_INST_MFSPR_SRR0 0x7c1a02a6
#define KVM_INST_MFSPR_SRR1 0x7c1b02a6
#define KVM_INST_MFSPR_DAR 0x7c1302a6
#define KVM_INST_MFSPR_DSISR 0x7c1202a6
#define KVM_INST_MTSPR_SPRG0 0x7c1043a6
#define KVM_INST_MTSPR_SPRG1 0x7c1143a6
#define KVM_INST_MTSPR_SPRG2 0x7c1243a6
#define KVM_INST_MTSPR_SPRG3 0x7c1343a6
#define KVM_INST_MTSPR_SRR0 0x7c1a03a6
#define KVM_INST_MTSPR_SRR1 0x7c1b03a6
#define KVM_INST_MTSPR_DAR 0x7c1303a6
#define KVM_INST_MTSPR_DSISR 0x7c1203a6
#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_WRTEEI_0 0x7c000146
#define KVM_INST_WRTEEI_1 0x7c008146
#define KVM_INST_MTSRIN 0x7c0001e4
static bool kvm_patching_worked = true;
static 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_wrteei_branch_offs;
extern u32 kvm_emulate_wrteei_ee_offs;
extern u32 kvm_emulate_wrteei_len;
extern u32 kvm_emulate_wrteei[];
static void kvm_patch_ins_wrteei(u32 *inst)
{
u32 *p;
int distance_start;
int distance_end;
ulong next_inst;
p = kvm_alloc(kvm_emulate_wrteei_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_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_wrteei, kvm_emulate_wrteei_len * 4);
p[kvm_emulate_wrteei_branch_offs] |= distance_end & KVM_INST_B_MASK;
p[kvm_emulate_wrteei_ee_offs] |= (*inst & MSR_EE);
flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrteei_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];
ulong out[8];
in[0] = KVM_MAGIC_PAGE;
in[1] = KVM_MAGIC_PAGE;
kvm_hypercall(in, out, HC_VENDOR_KVM | 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_SPRG0:
kvm_patch_ins_ld(inst, magic_var(sprg0), inst_rt);
break;
case KVM_INST_MFSPR_SPRG1:
kvm_patch_ins_ld(inst, magic_var(sprg1), inst_rt);
break;
case KVM_INST_MFSPR_SPRG2:
kvm_patch_ins_ld(inst, magic_var(sprg2), inst_rt);
break;
case KVM_INST_MFSPR_SPRG3:
kvm_patch_ins_ld(inst, magic_var(sprg3), inst_rt);
break;
case KVM_INST_MFSPR_SRR0:
kvm_patch_ins_ld(inst, magic_var(srr0), inst_rt);
break;
case KVM_INST_MFSPR_SRR1:
kvm_patch_ins_ld(inst, magic_var(srr1), inst_rt);
break;
case KVM_INST_MFSPR_DAR:
kvm_patch_ins_ld(inst, magic_var(dar), inst_rt);
break;
case KVM_INST_MFSPR_DSISR:
kvm_patch_ins_lwz(inst, magic_var(dsisr), inst_rt);
break;
/* Stores */
case KVM_INST_MTSPR_SPRG0:
kvm_patch_ins_std(inst, magic_var(sprg0), inst_rt);
break;
case KVM_INST_MTSPR_SPRG1:
kvm_patch_ins_std(inst, magic_var(sprg1), inst_rt);
break;
case KVM_INST_MTSPR_SPRG2:
kvm_patch_ins_std(inst, magic_var(sprg2), inst_rt);
break;
case KVM_INST_MTSPR_SPRG3:
kvm_patch_ins_std(inst, magic_var(sprg3), inst_rt);
break;
case KVM_INST_MTSPR_SRR0:
kvm_patch_ins_std(inst, magic_var(srr0), inst_rt);
break;
case KVM_INST_MTSPR_SRR1:
kvm_patch_ins_std(inst, magic_var(srr1), inst_rt);
break;
case KVM_INST_MTSPR_DAR:
kvm_patch_ins_std(inst, magic_var(dar), inst_rt);
break;
case KVM_INST_MTSPR_DSISR:
kvm_patch_ins_stw(inst, magic_var(dsisr), inst_rt);
break;
/* 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;
}
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:
case KVM_INST_WRTEEI_1:
kvm_patch_ins_wrteei(inst);
break;
#endif
}
}
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;
for (p = start; p < end; p++)
kvm_check_ins(p, features);
printk(KERN_INFO "KVM: Live patching for a fast VM %s\n",
kvm_patching_worked ? "worked" : "failed");
}
unsigned long kvm_hypercall(unsigned long *in,
unsigned long *out,
unsigned long nr)
{
unsigned long register r0 asm("r0");
unsigned long register r3 asm("r3") = in[0];
unsigned long register r4 asm("r4") = in[1];
unsigned long register r5 asm("r5") = in[2];
unsigned long register r6 asm("r6") = in[3];
unsigned long register r7 asm("r7") = in[4];
unsigned long register r8 asm("r8") = in[5];
unsigned long register r9 asm("r9") = in[6];
unsigned long register r10 asm("r10") = in[7];
unsigned long register r11 asm("r11") = nr;
unsigned long register r12 asm("r12");
asm volatile("bl kvm_hypercall_start"
: "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6),
"=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11),
"=r"(r12)
: "r"(r3), "r"(r4), "r"(r5), "r"(r6), "r"(r7), "r"(r8),
"r"(r9), "r"(r10), "r"(r11)
: "memory", "cc", "xer", "ctr", "lr");
out[0] = r4;
out[1] = r5;
out[2] = r6;
out[3] = r7;
out[4] = r8;
out[5] = r9;
out[6] = r10;
out[7] = r11;
return r3;
}
EXPORT_SYMBOL_GPL(kvm_hypercall);
static int kvm_para_setup(void)
{
extern u32 kvm_hypercall_start;
struct device_node *hyper_node;
u32 *insts;
int len, i;
hyper_node = of_find_node_by_path("/hypervisor");
if (!hyper_node)
return -1;
insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len);
if (len % 4)
return -1;
if (len > (4 * 4))
return -1;
for (i = 0; i < (len / 4); i++)
kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]);
return 0;
}
static __init void kvm_free_tmp(void)
{
unsigned long start, end;
start = (ulong)&kvm_tmp[kvm_tmp_index + (PAGE_SIZE - 1)] & PAGE_MASK;
end = (ulong)&kvm_tmp[ARRAY_SIZE(kvm_tmp)] & PAGE_MASK;
/* Free the tmp space we don't need */
for (; start < end; start += PAGE_SIZE) {
ClearPageReserved(virt_to_page(start));
init_page_count(virt_to_page(start));
free_page(start);
totalram_pages++;
}
}
static int __init kvm_guest_init(void)
{
if (!kvm_para_available())
goto free_tmp;
if (kvm_para_setup())
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);
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