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c3edd62851
xemu/target-s390x/mmu_helper.c
Thomas Huth c3edd62851 s390x/mmu: Add function for accessing guest memory 
According to the POP specification, the parameter blocks of various
functions like the IO instructions are accessed with logical addresses.
Thus we need a function that can read or write a buffer from/to the
guest's logical address space.

This patch now provides a function that can be used to access virtual
guest memory by using the mmu_translate function of QEMU to convert
the virtual addresses to physical.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2015-02-18 09:37:15 +01:00

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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 == 1 ? 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 == 1 ? 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 == 2) {
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 == 1) && !(*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 occured
* @return 0 if the translation was successfull, -1 if a fault occured
*/
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 == 2) {
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
* @hostbuf: buffer in host memory. NULL = do only checks w/o copying
* @len: length that should be transfered
* @is_write: true = write, false = read
* Returns: 0 on success, non-zero if an exception occured
*
* 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, void *hostbuf,
int len, bool is_write)
{
int currlen, nr_pages, i;
target_ulong *pages;
int 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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