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xemu/target-s390x/mmu_helper.c
Alexander Graf 9814fed0af target-s390x: Only access allocated storage keys 
We allocate ram_size / PAGE_SIZE storage keys, so we need to make sure that
we only access that many. Unfortunately the code can overrun this array by
one, potentially overwriting unrelated memory.

Fix it by limiting storage keys to their scope.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
2015-06-05 01:38:00 +02:00

481 lines
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C
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/*
* S390x MMU related functions
*
* Copyright (c) 2011 Alexander Graf
* Copyright (c) 2015 Thomas Huth, IBM Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*/
#include "qemu/error-report.h"
#include "exec/address-spaces.h"
#include "sysemu/kvm.h"
#include "cpu.h"
/* #define DEBUG_S390 */
/* #define DEBUG_S390_PTE */
/* #define DEBUG_S390_STDOUT */
#ifdef DEBUG_S390
#ifdef DEBUG_S390_STDOUT
#define DPRINTF(fmt, ...) \
do { fprintf(stderr, fmt, ## __VA_ARGS__); \
qemu_log(fmt, ##__VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
do { qemu_log(fmt, ## __VA_ARGS__); } while (0)
#endif
#else
#define DPRINTF(fmt, ...) \
do { } while (0)
#endif
#ifdef DEBUG_S390_PTE
#define PTE_DPRINTF DPRINTF
#else
#define PTE_DPRINTF(fmt, ...) \
do { } while (0)
#endif
/* Fetch/store bits in the translation exception code: */
#define FS_READ 0x800
#define FS_WRITE 0x400
static void trigger_access_exception(CPUS390XState *env, uint32_t type,
uint32_t ilen, uint64_t tec)
{
S390CPU *cpu = s390_env_get_cpu(env);
if (kvm_enabled()) {
kvm_s390_access_exception(cpu, type, tec);
} else {
CPUState *cs = CPU(cpu);
stq_phys(cs->as, env->psa + offsetof(LowCore, trans_exc_code), tec);
trigger_pgm_exception(env, type, ilen);
}
}
static void trigger_prot_fault(CPUS390XState *env, target_ulong vaddr,
uint64_t asc, int rw, bool exc)
{
uint64_t tec;
tec = vaddr | (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ) | 4 | asc >> 46;
DPRINTF("%s: trans_exc_code=%016" PRIx64 "\n", __func__, tec);
if (!exc) {
return;
}
trigger_access_exception(env, PGM_PROTECTION, ILEN_LATER_INC, tec);
}
static void trigger_page_fault(CPUS390XState *env, target_ulong vaddr,
uint32_t type, uint64_t asc, int rw, bool exc)
{
int ilen = ILEN_LATER;
uint64_t tec;
tec = vaddr | (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ) | asc >> 46;
DPRINTF("%s: vaddr=%016" PRIx64 " bits=%d\n", __func__, vaddr, bits);
if (!exc) {
return;
}
/* Code accesses have an undefined ilc. */
if (rw == MMU_INST_FETCH) {
ilen = 2;
}
trigger_access_exception(env, type, ilen, tec);
}
/**
* Translate real address to absolute (= physical)
* address by taking care of the prefix mapping.
*/
static target_ulong mmu_real2abs(CPUS390XState *env, target_ulong raddr)
{
if (raddr < 0x2000) {
return raddr + env->psa; /* Map the lowcore. */
} else if (raddr >= env->psa && raddr < env->psa + 0x2000) {
return raddr - env->psa; /* Map the 0 page. */
}
return raddr;
}
/* Decode page table entry (normal 4KB page) */
static int mmu_translate_pte(CPUS390XState *env, target_ulong vaddr,
uint64_t asc, uint64_t pt_entry,
target_ulong *raddr, int *flags, int rw, bool exc)
{
if (pt_entry & _PAGE_INVALID) {
DPRINTF("%s: PTE=0x%" PRIx64 " invalid\n", __func__, pt_entry);
trigger_page_fault(env, vaddr, PGM_PAGE_TRANS, asc, rw, exc);
return -1;
}
if (pt_entry & _PAGE_RES0) {
trigger_page_fault(env, vaddr, PGM_TRANS_SPEC, asc, rw, exc);
return -1;
}
if (pt_entry & _PAGE_RO) {
*flags &= ~PAGE_WRITE;
}
*raddr = pt_entry & _ASCE_ORIGIN;
PTE_DPRINTF("%s: PTE=0x%" PRIx64 "\n", __func__, pt_entry);
return 0;
}
#define VADDR_PX 0xff000 /* Page index bits */
/* Decode segment table entry */
static int mmu_translate_segment(CPUS390XState *env, target_ulong vaddr,
uint64_t asc, uint64_t st_entry,
target_ulong *raddr, int *flags, int rw,
bool exc)
{
CPUState *cs = CPU(s390_env_get_cpu(env));
uint64_t origin, offs, pt_entry;
if (st_entry & _SEGMENT_ENTRY_RO) {
*flags &= ~PAGE_WRITE;
}
if ((st_entry & _SEGMENT_ENTRY_FC) && (env->cregs[0] & CR0_EDAT)) {
/* Decode EDAT1 segment frame absolute address (1MB page) */
*raddr = (st_entry & 0xfffffffffff00000ULL) | (vaddr & 0xfffff);
PTE_DPRINTF("%s: SEG=0x%" PRIx64 "\n", __func__, st_entry);
return 0;
}
/* Look up 4KB page entry */
origin = st_entry & _SEGMENT_ENTRY_ORIGIN;
offs = (vaddr & VADDR_PX) >> 9;
pt_entry = ldq_phys(cs->as, origin + offs);
PTE_DPRINTF("%s: 0x%" PRIx64 " + 0x%" PRIx64 " => 0x%016" PRIx64 "\n",
__func__, origin, offs, pt_entry);
return mmu_translate_pte(env, vaddr, asc, pt_entry, raddr, flags, rw, exc);
}
/* Decode region table entries */
static int mmu_translate_region(CPUS390XState *env, target_ulong vaddr,
uint64_t asc, uint64_t entry, int level,
target_ulong *raddr, int *flags, int rw,
bool exc)
{
CPUState *cs = CPU(s390_env_get_cpu(env));
uint64_t origin, offs, new_entry;
const int pchks[4] = {
PGM_SEGMENT_TRANS, PGM_REG_THIRD_TRANS,
PGM_REG_SEC_TRANS, PGM_REG_FIRST_TRANS
};
PTE_DPRINTF("%s: 0x%" PRIx64 "\n", __func__, entry);
origin = entry & _REGION_ENTRY_ORIGIN;
offs = (vaddr >> (17 + 11 * level / 4)) & 0x3ff8;
new_entry = ldq_phys(cs->as, origin + offs);
PTE_DPRINTF("%s: 0x%" PRIx64 " + 0x%" PRIx64 " => 0x%016" PRIx64 "\n",
__func__, origin, offs, new_entry);
if ((new_entry & _REGION_ENTRY_INV) != 0) {
DPRINTF("%s: invalid region\n", __func__);
trigger_page_fault(env, vaddr, pchks[level / 4], asc, rw, exc);
return -1;
}
if ((new_entry & _REGION_ENTRY_TYPE_MASK) != level) {
trigger_page_fault(env, vaddr, PGM_TRANS_SPEC, asc, rw, exc);
return -1;
}
if (level == _ASCE_TYPE_SEGMENT) {
return mmu_translate_segment(env, vaddr, asc, new_entry, raddr, flags,
rw, exc);
}
/* Check region table offset and length */
offs = (vaddr >> (28 + 11 * (level - 4) / 4)) & 3;
if (offs < ((new_entry & _REGION_ENTRY_TF) >> 6)
|| offs > (new_entry & _REGION_ENTRY_LENGTH)) {
DPRINTF("%s: invalid offset or len (%lx)\n", __func__, new_entry);
trigger_page_fault(env, vaddr, pchks[level / 4 - 1], asc, rw, exc);
return -1;
}
if ((env->cregs[0] & CR0_EDAT) && (new_entry & _REGION_ENTRY_RO)) {
*flags &= ~PAGE_WRITE;
}
/* yet another region */
return mmu_translate_region(env, vaddr, asc, new_entry, level - 4,
raddr, flags, rw, exc);
}
static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
uint64_t asc, uint64_t asce, target_ulong *raddr,
int *flags, int rw, bool exc)
{
int level;
int r;
if (asce & _ASCE_REAL_SPACE) {
/* direct mapping */
*raddr = vaddr;
return 0;
}
level = asce & _ASCE_TYPE_MASK;
switch (level) {
case _ASCE_TYPE_REGION1:
if ((vaddr >> 62) > (asce & _ASCE_TABLE_LENGTH)) {
trigger_page_fault(env, vaddr, PGM_REG_FIRST_TRANS, asc, rw, exc);
return -1;
}
break;
case _ASCE_TYPE_REGION2:
if (vaddr & 0xffe0000000000000ULL) {
DPRINTF("%s: vaddr doesn't fit 0x%16" PRIx64
" 0xffe0000000000000ULL\n", __func__, vaddr);
trigger_page_fault(env, vaddr, PGM_ASCE_TYPE, asc, rw, exc);
return -1;
}
if ((vaddr >> 51 & 3) > (asce & _ASCE_TABLE_LENGTH)) {
trigger_page_fault(env, vaddr, PGM_REG_SEC_TRANS, asc, rw, exc);
return -1;
}
break;
case _ASCE_TYPE_REGION3:
if (vaddr & 0xfffffc0000000000ULL) {
DPRINTF("%s: vaddr doesn't fit 0x%16" PRIx64
" 0xfffffc0000000000ULL\n", __func__, vaddr);
trigger_page_fault(env, vaddr, PGM_ASCE_TYPE, asc, rw, exc);
return -1;
}
if ((vaddr >> 40 & 3) > (asce & _ASCE_TABLE_LENGTH)) {
trigger_page_fault(env, vaddr, PGM_REG_THIRD_TRANS, asc, rw, exc);
return -1;
}
break;
case _ASCE_TYPE_SEGMENT:
if (vaddr & 0xffffffff80000000ULL) {
DPRINTF("%s: vaddr doesn't fit 0x%16" PRIx64
" 0xffffffff80000000ULL\n", __func__, vaddr);
trigger_page_fault(env, vaddr, PGM_ASCE_TYPE, asc, rw, exc);
return -1;
}
if ((vaddr >> 29 & 3) > (asce & _ASCE_TABLE_LENGTH)) {
trigger_page_fault(env, vaddr, PGM_SEGMENT_TRANS, asc, rw, exc);
return -1;
}
break;
}
r = mmu_translate_region(env, vaddr, asc, asce, level, raddr, flags, rw,
exc);
if (rw == MMU_DATA_STORE && !(*flags & PAGE_WRITE)) {
trigger_prot_fault(env, vaddr, asc, rw, exc);
return -1;
}
return r;
}
/**
* Translate a virtual (logical) address into a physical (absolute) address.
* @param vaddr the virtual address
* @param rw 0 = read, 1 = write, 2 = code fetch
* @param asc address space control (one of the PSW_ASC_* modes)
* @param raddr the translated address is stored to this pointer
* @param flags the PAGE_READ/WRITE/EXEC flags are stored to this pointer
* @param exc true = inject a program check if a fault occurred
* @return 0 if the translation was successful, -1 if a fault occurred
*/
int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
target_ulong *raddr, int *flags, bool exc)
{
int r = -1;
uint8_t *sk;
*flags = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
vaddr &= TARGET_PAGE_MASK;
if (!(env->psw.mask & PSW_MASK_DAT)) {
*raddr = vaddr;
r = 0;
goto out;
}
switch (asc) {
case PSW_ASC_PRIMARY:
PTE_DPRINTF("%s: asc=primary\n", __func__);
r = mmu_translate_asce(env, vaddr, asc, env->cregs[1], raddr, flags,
rw, exc);
break;
case PSW_ASC_HOME:
PTE_DPRINTF("%s: asc=home\n", __func__);
r = mmu_translate_asce(env, vaddr, asc, env->cregs[13], raddr, flags,
rw, exc);
break;
case PSW_ASC_SECONDARY:
PTE_DPRINTF("%s: asc=secondary\n", __func__);
/*
* Instruction: Primary
* Data: Secondary
*/
if (rw == MMU_INST_FETCH) {
r = mmu_translate_asce(env, vaddr, PSW_ASC_PRIMARY, env->cregs[1],
raddr, flags, rw, exc);
*flags &= ~(PAGE_READ | PAGE_WRITE);
} else {
r = mmu_translate_asce(env, vaddr, PSW_ASC_SECONDARY, env->cregs[7],
raddr, flags, rw, exc);
*flags &= ~(PAGE_EXEC);
}
break;
case PSW_ASC_ACCREG:
default:
hw_error("guest switched to unknown asc mode\n");
break;
}
out:
/* Convert real address -> absolute address */
*raddr = mmu_real2abs(env, *raddr);
if (*raddr < ram_size) {
sk = &env->storage_keys[*raddr / TARGET_PAGE_SIZE];
if (*flags & PAGE_READ) {
*sk |= SK_R;
}
if (*flags & PAGE_WRITE) {
*sk |= SK_C;
}
}
return r;
}
/**
* lowprot_enabled: Check whether low-address protection is enabled
*/
static bool lowprot_enabled(const CPUS390XState *env)
{
if (!(env->cregs[0] & CR0_LOWPROT)) {
return false;
}
if (!(env->psw.mask & PSW_MASK_DAT)) {
return true;
}
/* Check the private-space control bit */
switch (env->psw.mask & PSW_MASK_ASC) {
case PSW_ASC_PRIMARY:
return !(env->cregs[1] & _ASCE_PRIVATE_SPACE);
case PSW_ASC_SECONDARY:
return !(env->cregs[7] & _ASCE_PRIVATE_SPACE);
case PSW_ASC_HOME:
return !(env->cregs[13] & _ASCE_PRIVATE_SPACE);
default:
/* We don't support access register mode */
error_report("unsupported addressing mode");
exit(1);
}
}
/**
* translate_pages: Translate a set of consecutive logical page addresses
* to absolute addresses
*/
static int translate_pages(S390CPU *cpu, vaddr addr, int nr_pages,
target_ulong *pages, bool is_write)
{
bool lowprot = is_write && lowprot_enabled(&cpu->env);
uint64_t asc = cpu->env.psw.mask & PSW_MASK_ASC;
CPUS390XState *env = &cpu->env;
int ret, i, pflags;
for (i = 0; i < nr_pages; i++) {
/* Low-address protection? */
if (lowprot && (addr < 512 || (addr >= 4096 && addr < 4096 + 512))) {
trigger_access_exception(env, PGM_PROTECTION, ILEN_LATER_INC, 0);
return -EACCES;
}
ret = mmu_translate(env, addr, is_write, asc, &pages[i], &pflags, true);
if (ret) {
return ret;
}
if (!address_space_access_valid(&address_space_memory, pages[i],
TARGET_PAGE_SIZE, is_write)) {
program_interrupt(env, PGM_ADDRESSING, 0);
return -EFAULT;
}
addr += TARGET_PAGE_SIZE;
}
return 0;
}
/**
* s390_cpu_virt_mem_rw:
* @laddr: the logical start address
* @ar: the access register number
* @hostbuf: buffer in host memory. NULL = do only checks w/o copying
* @len: length that should be transferred
* @is_write: true = write, false = read
* Returns: 0 on success, non-zero if an exception occurred
*
* Copy from/to guest memory using logical addresses. Note that we inject a
* program interrupt in case there is an error while accessing the memory.
*/
int s390_cpu_virt_mem_rw(S390CPU *cpu, vaddr laddr, uint8_t ar, void *hostbuf,
int len, bool is_write)
{
int currlen, nr_pages, i;
target_ulong *pages;
int ret;
if (kvm_enabled()) {
ret = kvm_s390_mem_op(cpu, laddr, ar, hostbuf, len, is_write);
if (ret >= 0) {
return ret;
}
}
nr_pages = (((laddr & ~TARGET_PAGE_MASK) + len - 1) >> TARGET_PAGE_BITS)
+ 1;
pages = g_malloc(nr_pages * sizeof(*pages));
ret = translate_pages(cpu, laddr, nr_pages, pages, is_write);
if (ret == 0 && hostbuf != NULL) {
/* Copy data by stepping through the area page by page */
for (i = 0; i < nr_pages; i++) {
currlen = MIN(len, TARGET_PAGE_SIZE - (laddr % TARGET_PAGE_SIZE));
cpu_physical_memory_rw(pages[i] | (laddr & ~TARGET_PAGE_MASK),
hostbuf, currlen, is_write);
laddr += currlen;
hostbuf += currlen;
len -= currlen;
}
}
g_free(pages);
return ret;
}
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