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tcg: Widen CPUTLBEntry comparators to 64-bits

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This makes CPUTLBEntry agnostic to the address size of the guest.
When 32-bit addresses are in effect, we can simply read the low
32 bits of the 64-bit field.  Similarly when we need to update
the field for setting TLB_NOTDIRTY.

For TCG backends that could in theory be big-endian, but in
practice are not (arm, loongarch, riscv), use QEMU_BUILD_BUG_ON
to document and ensure this is not accidentally missed.

For s390x, which is always big-endian, use HOST_BIG_ENDIAN anyway,
to document the reason for the adjustment.

For sparc64 and ppc64, always perform a 64-bit load, and rely on
the following 32-bit comparison to ignore the high bits.

Rearrange mips and ppc if ladders for clarity.

Reviewed-by: Anton Johansson <anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-03-24 13:02:59 -07:00
parent ff0c61bf35
commit 238f43809a
11 changed files with 67 additions and 51 deletions
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19
include/exec/cpu_ldst.h
View file

@ -334,18 +334,25 @@ static inline target_ulong tlb_read_idx(const CPUTLBEntry *entry,
{
/* Do not rearrange the CPUTLBEntry structure members. */
QEMU_BUILD_BUG_ON(offsetof(CPUTLBEntry, addr_read) !=
MMU_DATA_LOAD * TARGET_LONG_SIZE);
MMU_DATA_LOAD * sizeof(uint64_t));
QEMU_BUILD_BUG_ON(offsetof(CPUTLBEntry, addr_write) !=
MMU_DATA_STORE * TARGET_LONG_SIZE);
MMU_DATA_STORE * sizeof(uint64_t));
QEMU_BUILD_BUG_ON(offsetof(CPUTLBEntry, addr_code) !=
MMU_INST_FETCH * TARGET_LONG_SIZE);
MMU_INST_FETCH * sizeof(uint64_t));
const target_ulong *ptr = &entry->addr_idx[access_type];
#if TCG_OVERSIZED_GUEST
return *ptr;
#if TARGET_LONG_BITS == 32
/* Use qatomic_read, in case of addr_write; only care about low bits. */
const uint32_t *ptr = (uint32_t *)&entry->addr_idx[access_type];
ptr += HOST_BIG_ENDIAN;
return qatomic_read(ptr);
#else
const uint64_t *ptr = &entry->addr_idx[access_type];
# if TCG_OVERSIZED_GUEST
return *ptr;
# else
/* ofs might correspond to .addr_write, so use qatomic_read */
return qatomic_read(ptr);
# endif
#endif
}