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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
Download patch file Download diff file Expand all files Collapse all files

37
include/exec/cpu-defs.h
View file

@ -65,11 +65,7 @@
/* use a fully associative victim tlb of 8 entries */
#define CPU_VTLB_SIZE 8
#if HOST_LONG_BITS == 32 && TARGET_LONG_BITS == 32
#define CPU_TLB_ENTRY_BITS 4
#else
#define CPU_TLB_ENTRY_BITS 5
#endif
#define CPU_TLB_DYN_MIN_BITS 6
#define CPU_TLB_DYN_DEFAULT_BITS 8
@ -95,33 +91,26 @@
# endif
/* Minimalized TLB entry for use by TCG fast path. */
typedef struct CPUTLBEntry {
/* bit TARGET_LONG_BITS to TARGET_PAGE_BITS : virtual address
bit TARGET_PAGE_BITS-1..4 : Nonzero for accesses that should not
go directly to ram.
bit 3 : indicates that the entry is invalid
bit 2..0 : zero
*/
union {
struct {
target_ulong addr_read;
target_ulong addr_write;
target_ulong addr_code;
/* Addend to virtual address to get host address. IO accesses
use the corresponding iotlb value. */
uintptr_t addend;
};
typedef union CPUTLBEntry {
struct {
uint64_t addr_read;
uint64_t addr_write;
uint64_t addr_code;
/*
* Padding to get a power of two size, as well as index
* access to addr_{read,write,code}.
* Addend to virtual address to get host address. IO accesses
* use the corresponding iotlb value.
*/
target_ulong addr_idx[(1 << CPU_TLB_ENTRY_BITS) / TARGET_LONG_SIZE];
uintptr_t addend;
};
/*
* Padding to get a power of two size, as well as index
* access to addr_{read,write,code}.
*/
uint64_t addr_idx[(1 << CPU_TLB_ENTRY_BITS) / sizeof(uint64_t)];
} CPUTLBEntry;
QEMU_BUILD_BUG_ON(sizeof(CPUTLBEntry) != (1 << CPU_TLB_ENTRY_BITS));
#endif /* !CONFIG_USER_ONLY && CONFIG_TCG */
#if !defined(CONFIG_USER_ONLY)

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
}