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s390x/mmu: Inject PGM_ADDRESSING on bogus table addresses

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Let's document how it works and inject PGM_ADDRESSING if reading of
table entries fails.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
This commit is contained in:
David Hildenbrand 2019-09-25 12:08:19 +02:00
parent 81d7e3bc45
commit 2ed0cd7cd7
1 changed files with 27 additions and 4 deletions
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31
target/s390x/mmu_helper.c
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@ -93,6 +93,27 @@ target_ulong mmu_real2abs(CPUS390XState *env, target_ulong raddr)
return raddr;
}
static inline bool read_table_entry(CPUS390XState *env, hwaddr gaddr,
uint64_t *entry)
{
CPUState *cs = env_cpu(env);
/*
* According to the PoP, these table addresses are "unpredictably real
* or absolute". Also, "it is unpredictable whether the address wraps
* or an addressing exception is recognized".
*
* We treat them as absolute addresses and don't wrap them.
*/
if (unlikely(address_space_read(cs->as, gaddr, MEMTXATTRS_UNSPECIFIED,
(uint8_t *)entry, sizeof(*entry)) !=
MEMTX_OK)) {
return false;
}
*entry = be64_to_cpu(*entry);
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,
@ -118,7 +139,6 @@ static int mmu_translate_segment(CPUS390XState *env, target_ulong vaddr,
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) {
@ -134,7 +154,9 @@ static int mmu_translate_segment(CPUS390XState *env, target_ulong vaddr,
/* Look up 4KB page entry */
origin = st_entry & SEGMENT_ENTRY_ORIGIN;
offs = (vaddr & VADDR_PX) >> 9;
pt_entry = ldq_phys(cs->as, origin + offs);
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);
}
@ -144,7 +166,6 @@ static int mmu_translate_region(CPUS390XState *env, target_ulong vaddr,
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,
@ -154,7 +175,9 @@ static int mmu_translate_region(CPUS390XState *env, target_ulong vaddr,
origin = entry & REGION_ENTRY_ORIGIN;
offs = (vaddr >> (17 + 11 * level / 4)) & 0x3ff8;
new_entry = ldq_phys(cs->as, origin + offs);
if (!read_table_entry(env, origin + offs, &new_entry)) {
return PGM_ADDRESSING;
}
if ((new_entry & REGION_ENTRY_INV) != 0) {
return pchks[level / 4];