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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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8
accel/tcg/cputlb.c
View file

@ -1000,11 +1000,15 @@ static void tlb_reset_dirty_range_locked(CPUTLBEntry *tlb_entry,
addr &= TARGET_PAGE_MASK;
addr += tlb_entry->addend;
if ((addr - start) < length) {
#if TCG_OVERSIZED_GUEST
#if TARGET_LONG_BITS == 32
uint32_t *ptr_write = (uint32_t *)&tlb_entry->addr_write;
ptr_write += HOST_BIG_ENDIAN;
qatomic_set(ptr_write, *ptr_write | TLB_NOTDIRTY);
#elif TCG_OVERSIZED_GUEST
tlb_entry->addr_write |= TLB_NOTDIRTY;
#else
qatomic_set(&tlb_entry->addr_write,
tlb_entry->addr_write | TLB_NOTDIRTY);
tlb_entry->addr_write | TLB_NOTDIRTY);
#endif
}
}

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
}

1
tcg/aarch64/tcg-target.c.inc
View file

@ -1690,6 +1690,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
tcg_out_insn(s, 3502, ADD, 1, TCG_REG_TMP1, TCG_REG_TMP1, TCG_REG_TMP0);
/* Load the tlb comparator into TMP0, and the fast path addend into TMP1. */
QEMU_BUILD_BUG_ON(HOST_BIG_ENDIAN);
tcg_out_ld(s, addr_type, TCG_REG_TMP0, TCG_REG_TMP1,
is_ld ? offsetof(CPUTLBEntry, addr_read)
: offsetof(CPUTLBEntry, addr_write));

1
tcg/arm/tcg-target.c.inc
View file

@ -1430,6 +1430,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
* Add the tlb_table pointer, creating the CPUTLBEntry address in R1.
* Load the tlb comparator into R2/R3 and the fast path addend into R1.
*/
QEMU_BUILD_BUG_ON(HOST_BIG_ENDIAN);
if (cmp_off == 0) {
if (s->addr_type == TCG_TYPE_I32) {
tcg_out_ld32_rwb(s, COND_AL, TCG_REG_R2, TCG_REG_R1, TCG_REG_R0);

1
tcg/loongarch64/tcg-target.c.inc
View file

@ -875,6 +875,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
tcg_out_opc_add_d(s, TCG_REG_TMP2, TCG_REG_TMP2, TCG_REG_TMP1);
/* Load the tlb comparator and the addend. */
QEMU_BUILD_BUG_ON(HOST_BIG_ENDIAN);
tcg_out_ld(s, addr_type, TCG_REG_TMP0, TCG_REG_TMP2,
is_ld ? offsetof(CPUTLBEntry, addr_read)
: offsetof(CPUTLBEntry, addr_write));

13
tcg/mips/tcg-target.c.inc
View file

@ -1311,14 +1311,17 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
/* Add the tlb_table pointer, creating the CPUTLBEntry address in TMP3. */
tcg_out_opc_reg(s, ALIAS_PADD, TCG_TMP3, TCG_TMP3, TCG_TMP1);
if (TCG_TARGET_REG_BITS == 32 || addr_type == TCG_TYPE_I32) {
/* Load the (low half) tlb comparator. */
tcg_out_ld(s, TCG_TYPE_I32, TCG_TMP0, TCG_TMP3,
cmp_off + HOST_BIG_ENDIAN * 4);
} else {
tcg_out_ld(s, TCG_TYPE_I64, TCG_TMP0, TCG_TMP3, cmp_off);
}
if (TCG_TARGET_REG_BITS == 64 || addr_type == TCG_TYPE_I32) {
/* Load the tlb comparator. */
tcg_out_ld(s, addr_type, TCG_TMP0, TCG_TMP3, cmp_off);
/* Load the tlb addend for the fast path. */
tcg_out_ld(s, TCG_TYPE_PTR, TCG_TMP3, TCG_TMP3, add_off);
} else {
/* Load the low half of the tlb comparator. */
tcg_out_ldst(s, OPC_LW, TCG_TMP0, TCG_TMP3, cmp_off + LO_OFF);
}
/*

28
tcg/ppc/tcg-target.c.inc
View file

@ -2098,20 +2098,24 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
}
tcg_out32(s, AND | SAB(TCG_REG_TMP1, TCG_REG_TMP1, TCG_REG_R0));
/* Load the (low part) TLB comparator into TMP2. */
if (cmp_off == 0
&& (TCG_TARGET_REG_BITS == 64 || addr_type == TCG_TYPE_I32)) {
uint32_t lxu = (TCG_TARGET_REG_BITS == 32 || addr_type == TCG_TYPE_I32
? LWZUX : LDUX);
tcg_out32(s, lxu | TAB(TCG_REG_TMP2, TCG_REG_TMP1, TCG_REG_TMP2));
/*
* Load the (low part) TLB comparator into TMP2.
* For 64-bit host, always load the entire 64-bit slot for simplicity.
* We will ignore the high bits with tcg_out_cmp(..., addr_type).
*/
if (TCG_TARGET_REG_BITS == 64) {
if (cmp_off == 0) {
tcg_out32(s, LDUX | TAB(TCG_REG_TMP2, TCG_REG_TMP1, TCG_REG_TMP2));
} else {
tcg_out32(s, ADD | TAB(TCG_REG_TMP1, TCG_REG_TMP1, TCG_REG_TMP2));
tcg_out_ld(s, TCG_TYPE_I64, TCG_REG_TMP2, TCG_REG_TMP1, cmp_off);
}
} else if (cmp_off == 0 && !HOST_BIG_ENDIAN) {
tcg_out32(s, LWZUX | TAB(TCG_REG_TMP2, TCG_REG_TMP1, TCG_REG_TMP2));
} else {
tcg_out32(s, ADD | TAB(TCG_REG_TMP1, TCG_REG_TMP1, TCG_REG_TMP2));
if (TCG_TARGET_REG_BITS == 32 && addr_type != TCG_TYPE_I32) {
tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_TMP2,
TCG_REG_TMP1, cmp_off + 4 * HOST_BIG_ENDIAN);
} else {
tcg_out_ld(s, addr_type, TCG_REG_TMP2, TCG_REG_TMP1, cmp_off);
}
tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_TMP2, TCG_REG_TMP1,
cmp_off + 4 * HOST_BIG_ENDIAN);
}
/*

1
tcg/riscv/tcg-target.c.inc
View file

@ -1249,6 +1249,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, TCGReg *pbase,
}
/* Load the tlb comparator and the addend. */
QEMU_BUILD_BUG_ON(HOST_BIG_ENDIAN);
tcg_out_ld(s, addr_type, TCG_REG_TMP0, TCG_REG_TMP2,
is_ld ? offsetof(CPUTLBEntry, addr_read)
: offsetof(CPUTLBEntry, addr_write));

1
tcg/s390x/tcg-target.c.inc
View file

@ -1796,6 +1796,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
ofs = offsetof(CPUTLBEntry, addr_write);
}
if (addr_type == TCG_TYPE_I32) {
ofs += HOST_BIG_ENDIAN * 4;
tcg_out_insn(s, RX, C, TCG_REG_R0, TCG_TMP0, TCG_REG_NONE, ofs);
} else {
tcg_out_insn(s, RXY, CG, TCG_REG_R0, TCG_TMP0, TCG_REG_NONE, ofs);

8
tcg/sparc64/tcg-target.c.inc
View file

@ -1063,8 +1063,12 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
/* Add the tlb_table pointer, creating the CPUTLBEntry address into R2. */
tcg_out_arith(s, TCG_REG_T1, TCG_REG_T1, TCG_REG_T3, ARITH_ADD);
/* Load the tlb comparator and the addend. */
tcg_out_ld(s, addr_type, TCG_REG_T2, TCG_REG_T1, cmp_off);
/*
* Load the tlb comparator and the addend.
* Always load the entire 64-bit comparator for simplicity.
* We will ignore the high bits via BPCC_ICC below.
*/
tcg_out_ld(s, TCG_TYPE_I64, TCG_REG_T2, TCG_REG_T1, cmp_off);
tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_T1, TCG_REG_T1, add_off);
h->base = TCG_REG_T1;