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qemu-patch-raspberry4/target/s390x/mmu_helper.c
David Hildenbrand a780d096e6 s390x/mmu: Drop debug logging from MMU code 
Let's get it out of the way to make some further refactorings easier.
Personally, I've never used these debug statements at all. And if I had
to debug issues, I used plain GDB instead (debug prints are just way too
much noise in the MMU). We might want to introduce tracing at some point
instead, so we can able selected events on demand.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
2019-10-09 12:33:47 +02:00

549 lines
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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/osdep.h"
#include "qemu/error-report.h"
#include "exec/address-spaces.h"
#include "cpu.h"
#include "internal.h"
#include "kvm_s390x.h"
#include "sysemu/kvm.h"
#include "sysemu/tcg.h"
#include "exec/exec-all.h"
#include "trace.h"
#include "hw/hw.h"
#include "hw/s390x/storage-keys.h"
/* 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 = env_archcpu(env);
if (kvm_enabled()) {
kvm_s390_access_exception(cpu, type, tec);
} else {
CPUState *cs = env_cpu(env);
if (type != PGM_ADDRESSING) {
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;
if (!exc) {
return;
}
trigger_access_exception(env, PGM_PROTECTION, ILEN_AUTO, tec);
}
static void trigger_page_fault(CPUS390XState *env, target_ulong vaddr,
uint32_t type, uint64_t asc, int rw, bool exc)
{
int ilen = ILEN_AUTO;
uint64_t tec;
tec = vaddr | (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ) | asc >> 46;
if (!exc) {
return;
}
/* Code accesses have an undefined ilc. */
if (rw == MMU_INST_FETCH) {
ilen = 2;
}
trigger_access_exception(env, type, ilen, tec);
}
/* check whether the address would be proteted by Low-Address Protection */
static bool is_low_address(uint64_t addr)
{
return addr <= 511 || (addr >= 4096 && addr <= 4607);
}
/* check whether Low-Address Protection is enabled for mmu_translate() */
static bool lowprot_enabled(const CPUS390XState *env, uint64_t asc)
{
if (!(env->cregs[0] & CR0_LOWPROT)) {
return false;
}
if (!(env->psw.mask & PSW_MASK_DAT)) {
return true;
}
/* Check the private-space control bit */
switch (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 real address to absolute (= physical)
* address by taking care of the prefix mapping.
*/
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) {
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;
return 0;
}
/* 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 = env_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);
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);
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 = env_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
};
origin = entry & REGION_ENTRY_ORIGIN;
offs = (vaddr >> (17 + 11 * level / 4)) & 0x3ff8;
new_entry = ldq_phys(cs->as, origin + offs);
if ((new_entry & REGION_ENTRY_INV) != 0) {
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)) {
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) {
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) {
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) {
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 (!r && rw == MMU_DATA_STORE && !(*flags & PAGE_WRITE)) {
trigger_prot_fault(env, vaddr, asc, rw, exc);
return -1;
}
return r;
}
static void mmu_handle_skey(target_ulong addr, int rw, int *flags)
{
static S390SKeysClass *skeyclass;
static S390SKeysState *ss;
uint8_t key;
int rc;
if (unlikely(addr >= ram_size)) {
return;
}
if (unlikely(!ss)) {
ss = s390_get_skeys_device();
skeyclass = S390_SKEYS_GET_CLASS(ss);
}
/*
* Whenever we create a new TLB entry, we set the storage key reference
* bit. In case we allow write accesses, we set the storage key change
* bit. Whenever the guest changes the storage key, we have to flush the
* TLBs of all CPUs (the whole TLB or all affected entries), so that the
* next reference/change will result in an MMU fault and make us properly
* update the storage key here.
*
* Note 1: "record of references ... is not necessarily accurate",
* "change bit may be set in case no storing has occurred".
* -> We can set reference/change bits even on exceptions.
* Note 2: certain accesses seem to ignore storage keys. For example,
* DAT translation does not set reference bits for table accesses.
*
* TODO: key-controlled protection. Only CPU accesses make use of the
* PSW key. CSS accesses are different - we have to pass in the key.
*
* TODO: we have races between getting and setting the key.
*/
rc = skeyclass->get_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
if (rc) {
trace_get_skeys_nonzero(rc);
return;
}
switch (rw) {
case MMU_DATA_LOAD:
case MMU_INST_FETCH:
/*
* The TLB entry has to remain write-protected on read-faults if
* the storage key does not indicate a change already. Otherwise
* we might miss setting the change bit on write accesses.
*/
if (!(key & SK_C)) {
*flags &= ~PAGE_WRITE;
}
break;
case MMU_DATA_STORE:
key |= SK_C;
break;
default:
g_assert_not_reached();
}
/* Any store/fetch sets the reference bit */
key |= SK_R;
rc = skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
if (rc) {
trace_set_skeys_nonzero(rc);
}
}
/**
* 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)
{
uint64_t asce;
int r;
*flags = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
if (is_low_address(vaddr & TARGET_PAGE_MASK) && lowprot_enabled(env, asc)) {
/*
* If any part of this page is currently protected, make sure the
* TLB entry will not be reused.
*
* As the protected range is always the first 512 bytes of the
* two first pages, we are able to catch all writes to these areas
* just by looking at the start address (triggering the tlb miss).
*/
*flags |= PAGE_WRITE_INV;
if (is_low_address(vaddr) && rw == MMU_DATA_STORE) {
if (exc) {
trigger_access_exception(env, PGM_PROTECTION, ILEN_AUTO, 0);
}
return -EACCES;
}
}
vaddr &= TARGET_PAGE_MASK;
if (!(env->psw.mask & PSW_MASK_DAT)) {
*raddr = vaddr;
goto nodat;
}
switch (asc) {
case PSW_ASC_PRIMARY:
asce = env->cregs[1];
break;
case PSW_ASC_HOME:
asce = env->cregs[13];
break;
case PSW_ASC_SECONDARY:
asce = env->cregs[7];
break;
case PSW_ASC_ACCREG:
default:
hw_error("guest switched to unknown asc mode\n");
break;
}
/* perform the DAT translation */
r = mmu_translate_asce(env, vaddr, asc, asce, raddr, flags, rw, exc);
if (r) {
return r;
}
nodat:
/* Convert real address -> absolute address */
*raddr = mmu_real2abs(env, *raddr);
mmu_handle_skey(*raddr, rw, flags);
return 0;
}
/**
* translate_pages: Translate a set of consecutive logical page addresses
* to absolute addresses. This function is used for TCG and old KVM without
* the MEMOP interface.
*/
static int translate_pages(S390CPU *cpu, vaddr addr, int nr_pages,
target_ulong *pages, bool is_write)
{
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++) {
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,
MEMTXATTRS_UNSPECIFIED)) {
trigger_access_exception(env, PGM_ADDRESSING, ILEN_AUTO, 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.
*
* This function will always return (also for TCG), make sure to call
* s390_cpu_virt_mem_handle_exc() to properly exit the CPU loop.
*/
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;
}
void s390_cpu_virt_mem_handle_exc(S390CPU *cpu, uintptr_t ra)
{
/* KVM will handle the interrupt automatically, TCG has to exit the TB */
#ifdef CONFIG_TCG
if (tcg_enabled()) {
cpu_loop_exit_restore(CPU(cpu), ra);
}
#endif
}
/**
* Translate a real address into a physical (absolute) address.
* @param raddr the real address
* @param rw 0 = read, 1 = write, 2 = code fetch
* @param addr the translated address is stored to this pointer
* @param flags the PAGE_READ/WRITE/EXEC flags are stored to this pointer
* @return 0 if the translation was successful, < 0 if a fault occurred
*/
int mmu_translate_real(CPUS390XState *env, target_ulong raddr, int rw,
target_ulong *addr, int *flags)
{
const bool lowprot_enabled = env->cregs[0] & CR0_LOWPROT;
*flags = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
if (is_low_address(raddr & TARGET_PAGE_MASK) && lowprot_enabled) {
/* see comment in mmu_translate() how this works */
*flags |= PAGE_WRITE_INV;
if (is_low_address(raddr) && rw == MMU_DATA_STORE) {
trigger_access_exception(env, PGM_PROTECTION, ILEN_AUTO, 0);
return -EACCES;
}
}
*addr = mmu_real2abs(env, raddr & TARGET_PAGE_MASK);
mmu_handle_skey(*addr, rw, flags);
return 0;
}
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