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plugins: save value during memory accesses
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Different code paths handle memory accesses:
- tcg generated code
- load/store helpers
- atomic helpers

This value is saved in cpu->neg.plugin_mem_value_{high,low}. Values are
written only for accessed word size (upper bits are not set).

Atomic operations are doing read/write at the same time, so we generate
two memory callbacks instead of one, to allow plugins to access distinct
values.

For now, we can have access only up to 128 bits, thus split this in two
64 bits words. When QEMU will support wider operations, we'll be able to
reconsider this.

Reviewed-by: Richard Henderson <[email protected]>
Reviewed-by: Alex Bennée <[email protected]>
Signed-off-by: Pierrick Bouvier <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Alex Bennée <[email protected]>
Message-Id: <[email protected]>
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@pbo-linaro @stsquad
pbo-linaro authored and stsquad committed Sep 19, 2024
1 parent f63c987 commit b709da5
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Showing 7 changed files with 167 additions and 30 deletions.
13 changes: 12 additions & 1 deletion accel/tcg/atomic_common.c.inc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,9 +14,20 @@
*/

static void atomic_trace_rmw_post(CPUArchState *env, uint64_t addr,
uint64_t read_value_low,
uint64_t read_value_high,
uint64_t write_value_low,
uint64_t write_value_high,
MemOpIdx oi)
{
qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_RW);
if (cpu_plugin_mem_cbs_enabled(env_cpu(env))) {
qemu_plugin_vcpu_mem_cb(env_cpu(env), addr,
read_value_low, read_value_high,
oi, QEMU_PLUGIN_MEM_R);
qemu_plugin_vcpu_mem_cb(env_cpu(env), addr,
write_value_low, write_value_high,
oi, QEMU_PLUGIN_MEM_W);
}
}

/*
Expand Down
66 changes: 58 additions & 8 deletions accel/tcg/atomic_template.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,14 @@
# error unsupported data size
#endif

#if DATA_SIZE == 16
# define VALUE_LOW(val) int128_getlo(val)
# define VALUE_HIGH(val) int128_gethi(val)
#else
# define VALUE_LOW(val) val
# define VALUE_HIGH(val) 0
#endif

#if DATA_SIZE >= 4
# define ABI_TYPE DATA_TYPE
#else
Expand Down Expand Up @@ -83,7 +91,12 @@ ABI_TYPE ATOMIC_NAME(cmpxchg)(CPUArchState *env, abi_ptr addr,
ret = qatomic_cmpxchg__nocheck(haddr, cmpv, newv);
#endif
ATOMIC_MMU_CLEANUP;
atomic_trace_rmw_post(env, addr, oi);
atomic_trace_rmw_post(env, addr,
VALUE_LOW(ret),
VALUE_HIGH(ret),
VALUE_LOW(newv),
VALUE_HIGH(newv),
oi);
return ret;
}

Expand All @@ -97,7 +110,12 @@ ABI_TYPE ATOMIC_NAME(xchg)(CPUArchState *env, abi_ptr addr, ABI_TYPE val,

ret = qatomic_xchg__nocheck(haddr, val);
ATOMIC_MMU_CLEANUP;
atomic_trace_rmw_post(env, addr, oi);
atomic_trace_rmw_post(env, addr,
VALUE_LOW(ret),
VALUE_HIGH(ret),
VALUE_LOW(val),
VALUE_HIGH(val),
oi);
return ret;
}

Expand All @@ -109,7 +127,12 @@ ABI_TYPE ATOMIC_NAME(X)(CPUArchState *env, abi_ptr addr, \
haddr = atomic_mmu_lookup(env_cpu(env), addr, oi, DATA_SIZE, retaddr); \
ret = qatomic_##X(haddr, val); \
ATOMIC_MMU_CLEANUP; \
atomic_trace_rmw_post(env, addr, oi); \
atomic_trace_rmw_post(env, addr, \
VALUE_LOW(ret), \
VALUE_HIGH(ret), \
VALUE_LOW(val), \
VALUE_HIGH(val), \
oi); \
return ret; \
}

Expand Down Expand Up @@ -145,7 +168,12 @@ ABI_TYPE ATOMIC_NAME(X)(CPUArchState *env, abi_ptr addr, \
cmp = qatomic_cmpxchg__nocheck(haddr, old, new); \
} while (cmp != old); \
ATOMIC_MMU_CLEANUP; \
atomic_trace_rmw_post(env, addr, oi); \
atomic_trace_rmw_post(env, addr, \
VALUE_LOW(old), \
VALUE_HIGH(old), \
VALUE_LOW(xval), \
VALUE_HIGH(xval), \
oi); \
return RET; \
}

Expand Down Expand Up @@ -188,7 +216,12 @@ ABI_TYPE ATOMIC_NAME(cmpxchg)(CPUArchState *env, abi_ptr addr,
ret = qatomic_cmpxchg__nocheck(haddr, BSWAP(cmpv), BSWAP(newv));
#endif
ATOMIC_MMU_CLEANUP;
atomic_trace_rmw_post(env, addr, oi);
atomic_trace_rmw_post(env, addr,
VALUE_LOW(ret),
VALUE_HIGH(ret),
VALUE_LOW(newv),
VALUE_HIGH(newv),
oi);
return BSWAP(ret);
}

Expand All @@ -202,7 +235,12 @@ ABI_TYPE ATOMIC_NAME(xchg)(CPUArchState *env, abi_ptr addr, ABI_TYPE val,

ret = qatomic_xchg__nocheck(haddr, BSWAP(val));
ATOMIC_MMU_CLEANUP;
atomic_trace_rmw_post(env, addr, oi);
atomic_trace_rmw_post(env, addr,
VALUE_LOW(ret),
VALUE_HIGH(ret),
VALUE_LOW(val),
VALUE_HIGH(val),
oi);
return BSWAP(ret);
}

Expand All @@ -214,7 +252,12 @@ ABI_TYPE ATOMIC_NAME(X)(CPUArchState *env, abi_ptr addr, \
haddr = atomic_mmu_lookup(env_cpu(env), addr, oi, DATA_SIZE, retaddr); \
ret = qatomic_##X(haddr, BSWAP(val)); \
ATOMIC_MMU_CLEANUP; \
atomic_trace_rmw_post(env, addr, oi); \
atomic_trace_rmw_post(env, addr, \
VALUE_LOW(ret), \
VALUE_HIGH(ret), \
VALUE_LOW(val), \
VALUE_HIGH(val), \
oi); \
return BSWAP(ret); \
}

Expand Down Expand Up @@ -247,7 +290,12 @@ ABI_TYPE ATOMIC_NAME(X)(CPUArchState *env, abi_ptr addr, \
ldn = qatomic_cmpxchg__nocheck(haddr, ldo, BSWAP(new)); \
} while (ldo != ldn); \
ATOMIC_MMU_CLEANUP; \
atomic_trace_rmw_post(env, addr, oi); \
atomic_trace_rmw_post(env, addr, \
VALUE_LOW(old), \
VALUE_HIGH(old), \
VALUE_LOW(xval), \
VALUE_HIGH(xval), \
oi); \
return RET; \
}

Expand Down Expand Up @@ -281,3 +329,5 @@ GEN_ATOMIC_HELPER_FN(add_fetch, ADD, DATA_TYPE, new)
#undef SUFFIX
#undef DATA_SIZE
#undef SHIFT
#undef VALUE_LOW
#undef VALUE_HIGH
38 changes: 24 additions & 14 deletions accel/tcg/ldst_common.c.inc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -123,10 +123,15 @@ void helper_st_i128(CPUArchState *env, uint64_t addr, Int128 val, MemOpIdx oi)
* Load helpers for cpu_ldst.h
*/

static void plugin_load_cb(CPUArchState *env, abi_ptr addr, MemOpIdx oi)
static void plugin_load_cb(CPUArchState *env, abi_ptr addr,
uint64_t value_low,
uint64_t value_high,
MemOpIdx oi)
{
if (cpu_plugin_mem_cbs_enabled(env_cpu(env))) {
qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
qemu_plugin_vcpu_mem_cb(env_cpu(env), addr,
value_low, value_high,
oi, QEMU_PLUGIN_MEM_R);
}
}

Expand All @@ -136,7 +141,7 @@ uint8_t cpu_ldb_mmu(CPUArchState *env, abi_ptr addr, MemOpIdx oi, uintptr_t ra)

tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_UB);
ret = do_ld1_mmu(env_cpu(env), addr, oi, ra, MMU_DATA_LOAD);
plugin_load_cb(env, addr, oi);
plugin_load_cb(env, addr, ret, 0, oi);
return ret;
}

Expand All @@ -147,7 +152,7 @@ uint16_t cpu_ldw_mmu(CPUArchState *env, abi_ptr addr,

tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_16);
ret = do_ld2_mmu(env_cpu(env), addr, oi, ra, MMU_DATA_LOAD);
plugin_load_cb(env, addr, oi);
plugin_load_cb(env, addr, ret, 0, oi);
return ret;
}

Expand All @@ -158,7 +163,7 @@ uint32_t cpu_ldl_mmu(CPUArchState *env, abi_ptr addr,

tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_32);
ret = do_ld4_mmu(env_cpu(env), addr, oi, ra, MMU_DATA_LOAD);
plugin_load_cb(env, addr, oi);
plugin_load_cb(env, addr, ret, 0, oi);
return ret;
}

Expand All @@ -169,7 +174,7 @@ uint64_t cpu_ldq_mmu(CPUArchState *env, abi_ptr addr,

tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_64);
ret = do_ld8_mmu(env_cpu(env), addr, oi, ra, MMU_DATA_LOAD);
plugin_load_cb(env, addr, oi);
plugin_load_cb(env, addr, ret, 0, oi);
return ret;
}

Expand All @@ -180,58 +185,63 @@ Int128 cpu_ld16_mmu(CPUArchState *env, abi_ptr addr,

tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_128);
ret = do_ld16_mmu(env_cpu(env), addr, oi, ra);
plugin_load_cb(env, addr, oi);
plugin_load_cb(env, addr, int128_getlo(ret), int128_gethi(ret), oi);
return ret;
}

/*
* Store helpers for cpu_ldst.h
*/

static void plugin_store_cb(CPUArchState *env, abi_ptr addr, MemOpIdx oi)
static void plugin_store_cb(CPUArchState *env, abi_ptr addr,
uint64_t value_low,
uint64_t value_high,
MemOpIdx oi)
{
if (cpu_plugin_mem_cbs_enabled(env_cpu(env))) {
qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
qemu_plugin_vcpu_mem_cb(env_cpu(env), addr,
value_low, value_high,
oi, QEMU_PLUGIN_MEM_W);
}
}

void cpu_stb_mmu(CPUArchState *env, abi_ptr addr, uint8_t val,
MemOpIdx oi, uintptr_t retaddr)
{
helper_stb_mmu(env, addr, val, oi, retaddr);
plugin_store_cb(env, addr, oi);
plugin_store_cb(env, addr, val, 0, oi);
}

void cpu_stw_mmu(CPUArchState *env, abi_ptr addr, uint16_t val,
MemOpIdx oi, uintptr_t retaddr)
{
tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_16);
do_st2_mmu(env_cpu(env), addr, val, oi, retaddr);
plugin_store_cb(env, addr, oi);
plugin_store_cb(env, addr, val, 0, oi);
}

void cpu_stl_mmu(CPUArchState *env, abi_ptr addr, uint32_t val,
MemOpIdx oi, uintptr_t retaddr)
{
tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_32);
do_st4_mmu(env_cpu(env), addr, val, oi, retaddr);
plugin_store_cb(env, addr, oi);
plugin_store_cb(env, addr, val, 0, oi);
}

void cpu_stq_mmu(CPUArchState *env, abi_ptr addr, uint64_t val,
MemOpIdx oi, uintptr_t retaddr)
{
tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_64);
do_st8_mmu(env_cpu(env), addr, val, oi, retaddr);
plugin_store_cb(env, addr, oi);
plugin_store_cb(env, addr, val, 0, oi);
}

void cpu_st16_mmu(CPUArchState *env, abi_ptr addr, Int128 val,
MemOpIdx oi, uintptr_t retaddr)
{
tcg_debug_assert((get_memop(oi) & MO_SIZE) == MO_128);
do_st16_mmu(env_cpu(env), addr, val, oi, retaddr);
plugin_store_cb(env, addr, oi);
plugin_store_cb(env, addr, int128_getlo(val), int128_gethi(val), oi);
}

/*
Expand Down
4 changes: 4 additions & 0 deletions include/hw/core/cpu.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -350,6 +350,8 @@ typedef union IcountDecr {
* from CPUArchState, via small negative offsets.
* @can_do_io: True if memory-mapped IO is allowed.
* @plugin_mem_cbs: active plugin memory callbacks
* @plugin_mem_value_low: 64 lower bits of latest accessed mem value.
* @plugin_mem_value_high: 64 higher bits of latest accessed mem value.
*/
typedef struct CPUNegativeOffsetState {
CPUTLB tlb;
Expand All @@ -358,6 +360,8 @@ typedef struct CPUNegativeOffsetState {
* The callback pointer are accessed via TCG (see gen_empty_mem_helper).
*/
GArray *plugin_mem_cbs;
uint64_t plugin_mem_value_low;
uint64_t plugin_mem_value_high;
#endif
IcountDecr icount_decr;
bool can_do_io;
Expand Down
4 changes: 4 additions & 0 deletions include/qemu/plugin.h
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Original file line number Diff line number Diff line change
Expand Up @@ -167,6 +167,8 @@ qemu_plugin_vcpu_syscall(CPUState *cpu, int64_t num, uint64_t a1,
void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret);

void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr,
uint64_t value_low,
uint64_t value_high,
MemOpIdx oi, enum qemu_plugin_mem_rw rw);

void qemu_plugin_flush_cb(void);
Expand Down Expand Up @@ -251,6 +253,8 @@ void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret)
{ }

static inline void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr,
uint64_t value_low,
uint64_t value_high,
MemOpIdx oi,
enum qemu_plugin_mem_rw rw)
{ }
Expand Down
6 changes: 6 additions & 0 deletions plugins/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -602,6 +602,8 @@ void exec_inline_op(enum plugin_dyn_cb_type type,
}

void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr,
uint64_t value_low,
uint64_t value_high,
MemOpIdx oi, enum qemu_plugin_mem_rw rw)
{
GArray *arr = cpu->neg.plugin_mem_cbs;
Expand All @@ -610,6 +612,10 @@ void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr,
if (arr == NULL) {
return;
}

cpu->neg.plugin_mem_value_low = value_low;
cpu->neg.plugin_mem_value_high = value_high;

for (i = 0; i < arr->len; i++) {
struct qemu_plugin_dyn_cb *cb =
&g_array_index(arr, struct qemu_plugin_dyn_cb, i);
Expand Down
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