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s390x/mmu: Convert to non-recursive page table walk 

A non-recursive implementation allows to make better use of the
branch predictor, avoids function calls, and makes the implementation of
new features only for a subset of region table levels easier.

We can now directly compare our implementation to the KVM gaccess
implementation in arch/s390/kvm/gaccess.c:guest_translate().

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
master
David Hildenbrand 2019-09-25 14:24:42 +02:00
parent 3fd0e85f3f
commit a4e95b41a1
1 changed files with 108 additions and 100 deletions
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208
target/s390x/mmu_helper.c
View File

@ -114,107 +114,16 @@ static inline bool read_table_entry(CPUS390XState *env, hwaddr gaddr,
return true;
}
/* 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_ENTRY_I) {
return PGM_PAGE_TRANS;
}
if (pt_entry & PAGE_ENTRY_0) {
return PGM_TRANS_SPEC;
}
if (pt_entry & PAGE_ENTRY_P) {
*flags &= ~PAGE_WRITE;
}
*raddr = pt_entry & TARGET_PAGE_MASK;
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)
{
uint64_t origin, offs, pt_entry;
if (st_entry & SEGMENT_ENTRY_P) {
*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 & SEGMENT_ENTRY_SFAA) |
(vaddr & ~SEGMENT_ENTRY_SFAA);
return 0;
}
/* Look up 4KB page entry */
origin = st_entry & SEGMENT_ENTRY_ORIGIN;
offs = VADDR_PAGE_TX(vaddr) * 8;
if (!read_table_entry(env, origin + offs, &pt_entry)) {
return PGM_ADDRESSING;
}
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)
{
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;
if (!read_table_entry(env, origin + offs, &new_entry)) {
return PGM_ADDRESSING;
}
if (new_entry & REGION_ENTRY_I) {
return pchks[level / 4];
}
if ((new_entry & REGION_ENTRY_TT) != level) {
return PGM_TRANS_SPEC;
}
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_TL)) {
return pchks[level / 4 - 1];
}
if ((env->cregs[0] & CR0_EDAT) && (new_entry & REGION_ENTRY_P)) {
*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)
{
const bool edat1 = (env->cregs[0] & CR0_EDAT) &&
s390_has_feat(S390_FEAT_EDAT);
const int asce_tl = asce & ASCE_TABLE_LENGTH;
int level;
const int asce_p = asce & ASCE_PRIVATE_SPACE;
hwaddr gaddr = asce & ASCE_ORIGIN;
uint64_t entry;
if (asce & ASCE_REAL_SPACE) {
/* direct mapping */
@ -222,12 +131,12 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
return 0;
}
level = asce & ASCE_TYPE_MASK;
switch (level) {
switch (asce & ASCE_TYPE_MASK) {
case ASCE_TYPE_REGION1:
if (VADDR_REGION1_TL(vaddr) > asce_tl) {
return PGM_REG_FIRST_TRANS;
}
gaddr += VADDR_REGION1_TX(vaddr) * 8;
break;
case ASCE_TYPE_REGION2:
if (VADDR_REGION1_TX(vaddr)) {
@ -236,6 +145,7 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
if (VADDR_REGION2_TL(vaddr) > asce_tl) {
return PGM_REG_SEC_TRANS;
}
gaddr += VADDR_REGION2_TX(vaddr) * 8;
break;
case ASCE_TYPE_REGION3:
if (VADDR_REGION1_TX(vaddr) || VADDR_REGION2_TX(vaddr)) {
@ -244,6 +154,7 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
if (VADDR_REGION3_TL(vaddr) > asce_tl) {
return PGM_REG_THIRD_TRANS;
}
gaddr += VADDR_REGION3_TX(vaddr) * 8;
break;
case ASCE_TYPE_SEGMENT:
if (VADDR_REGION1_TX(vaddr) || VADDR_REGION2_TX(vaddr) ||
@ -253,11 +164,108 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
if (VADDR_SEGMENT_TL(vaddr) > asce_tl) {
return PGM_SEGMENT_TRANS;
}
gaddr += VADDR_SEGMENT_TX(vaddr) * 8;
break;
}
return mmu_translate_region(env, vaddr, asc, asce, level, raddr, flags, rw,
exc);
switch (asce & ASCE_TYPE_MASK) {
case ASCE_TYPE_REGION1:
if (!read_table_entry(env, gaddr, &entry)) {
return PGM_ADDRESSING;
}
if (entry & REGION_ENTRY_I) {
return PGM_REG_FIRST_TRANS;
}
if ((entry & REGION_ENTRY_TT) != REGION_ENTRY_TT_REGION1) {
return PGM_TRANS_SPEC;
}
if (VADDR_REGION2_TL(vaddr) < (entry & REGION_ENTRY_TF) >> 6 ||
VADDR_REGION2_TL(vaddr) > (entry & REGION_ENTRY_TL)) {
return PGM_REG_SEC_TRANS;
}
if (edat1 && (entry & REGION_ENTRY_P)) {
*flags &= ~PAGE_WRITE;
}
gaddr = (entry & REGION_ENTRY_ORIGIN) + VADDR_REGION2_TX(vaddr) * 8;
/* fall through */
case ASCE_TYPE_REGION2:
if (!read_table_entry(env, gaddr, &entry)) {
return PGM_ADDRESSING;
}
if (entry & REGION_ENTRY_I) {
return PGM_REG_SEC_TRANS;
}
if ((entry & REGION_ENTRY_TT) != REGION_ENTRY_TT_REGION2) {
return PGM_TRANS_SPEC;
}
if (VADDR_REGION3_TL(vaddr) < (entry & REGION_ENTRY_TF) >> 6 ||
VADDR_REGION3_TL(vaddr) > (entry & REGION_ENTRY_TL)) {
return PGM_REG_THIRD_TRANS;
}
if (edat1 && (entry & REGION_ENTRY_P)) {
*flags &= ~PAGE_WRITE;
}
gaddr = (entry & REGION_ENTRY_ORIGIN) + VADDR_REGION3_TX(vaddr) * 8;
/* fall through */
case ASCE_TYPE_REGION3:
if (!read_table_entry(env, gaddr, &entry)) {
return PGM_ADDRESSING;
}
if (entry & REGION_ENTRY_I) {
return PGM_REG_THIRD_TRANS;
}
if ((entry & REGION_ENTRY_TT) != REGION_ENTRY_TT_REGION3) {
return PGM_TRANS_SPEC;
}
if (VADDR_SEGMENT_TL(vaddr) < (entry & REGION_ENTRY_TF) >> 6 ||
VADDR_SEGMENT_TL(vaddr) > (entry & REGION_ENTRY_TL)) {
return PGM_SEGMENT_TRANS;
}
if (edat1 && (entry & REGION_ENTRY_P)) {
*flags &= ~PAGE_WRITE;
}
gaddr = (entry & REGION_ENTRY_ORIGIN) + VADDR_SEGMENT_TX(vaddr) * 8;
/* fall through */
case ASCE_TYPE_SEGMENT:
if (!read_table_entry(env, gaddr, &entry)) {
return PGM_ADDRESSING;
}
if (entry & SEGMENT_ENTRY_I) {
return PGM_SEGMENT_TRANS;
}
if ((entry & SEGMENT_ENTRY_TT) != SEGMENT_ENTRY_TT_SEGMENT) {
return PGM_TRANS_SPEC;
}
if ((entry & SEGMENT_ENTRY_CS) && asce_p) {
return PGM_TRANS_SPEC;
}
if (entry & SEGMENT_ENTRY_P) {
*flags &= ~PAGE_WRITE;
}
if (edat1 && (entry & SEGMENT_ENTRY_FC)) {
*raddr = (entry & SEGMENT_ENTRY_SFAA) |
(vaddr & ~SEGMENT_ENTRY_SFAA);
return 0;
}
gaddr = (entry & SEGMENT_ENTRY_ORIGIN) + VADDR_PAGE_TX(vaddr) * 8;
break;
}
if (!read_table_entry(env, gaddr, &entry)) {
return PGM_ADDRESSING;
}
if (entry & PAGE_ENTRY_I) {
return PGM_PAGE_TRANS;
}
if (entry & PAGE_ENTRY_0) {
return PGM_TRANS_SPEC;
}
if (entry & PAGE_ENTRY_P) {
*flags &= ~PAGE_WRITE;
}
*raddr = entry & TARGET_PAGE_MASK;
return 0;
}
static void mmu_handle_skey(target_ulong addr, int rw, int *flags)