Commit ab2ddc7b66 for qemu.org
commit ab2ddc7b662d34c242ddfcfbe35996417b047ce2
Author: Eric Auger <eric.auger@redhat.com>
Date: Fri Mar 6 09:01:12 2026 +0000
target/arm/machine: Use VMSTATE_VARRAY_INT32_ALLOC for cpreg arrays
This removes the need for explicitly allocating cpreg_vmstate arrays.
On post save we simply point to cpreg arrays and set the length
accordingly.
Remove VMSTATE_VARRAY_INT32 for cpreg_vmstate_array_len as now
the array is dynamically allocated.
Also add a trace point on post_load to trace potential mismatch
between the number of incoming cpregs versus current ones.
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20260304101625.1962633-3-eric.auger@redhat.com
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 6bfab90981..7389f2988c 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -265,15 +265,10 @@ void arm_init_cpreg_list(ARMCPU *cpu)
if (arraylen) {
cpu->cpreg_indexes = g_new(uint64_t, arraylen);
cpu->cpreg_values = g_new(uint64_t, arraylen);
- cpu->cpreg_vmstate_indexes = g_new(uint64_t, arraylen);
- cpu->cpreg_vmstate_values = g_new(uint64_t, arraylen);
} else {
cpu->cpreg_indexes = NULL;
cpu->cpreg_values = NULL;
- cpu->cpreg_vmstate_indexes = NULL;
- cpu->cpreg_vmstate_values = NULL;
}
- cpu->cpreg_vmstate_array_len = arraylen;
cpu->cpreg_array_len = 0;
g_hash_table_foreach(cpu->cp_regs, add_cpreg_to_list, cpu);
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index eaa065d726..555083e7aa 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -864,12 +864,7 @@ static int kvm_arm_init_cpreg_list(ARMCPU *cpu)
cpu->cpreg_indexes = g_renew(uint64_t, cpu->cpreg_indexes, arraylen);
cpu->cpreg_values = g_renew(uint64_t, cpu->cpreg_values, arraylen);
- cpu->cpreg_vmstate_indexes = g_renew(uint64_t, cpu->cpreg_vmstate_indexes,
- arraylen);
- cpu->cpreg_vmstate_values = g_renew(uint64_t, cpu->cpreg_vmstate_values,
- arraylen);
cpu->cpreg_array_len = arraylen;
- cpu->cpreg_vmstate_array_len = arraylen;
for (i = 0, arraylen = 0; i < rlp->n; i++) {
uint64_t regidx = rlp->reg[i];
diff --git a/target/arm/machine.c b/target/arm/machine.c
index bbaae34449..d3d4f2ddc1 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -1,5 +1,6 @@
#include "qemu/osdep.h"
#include "cpu.h"
+#include "trace.h"
#include "qemu/error-report.h"
#include "system/kvm.h"
#include "system/tcg.h"
@@ -984,11 +985,14 @@ static int cpu_pre_save(void *opaque)
}
}
+ /*
+ * On outbound migration, send the data in our cpreg_{values,indexes}
+ * arrays. The migration code will not allocate anything, but just
+ * reads the data pointed to by the VMSTATE_VARRAY_INT32_ALLOC() fields.
+ */
+ cpu->cpreg_vmstate_indexes = cpu->cpreg_indexes;
+ cpu->cpreg_vmstate_values = cpu->cpreg_values;
cpu->cpreg_vmstate_array_len = cpu->cpreg_array_len;
- memcpy(cpu->cpreg_vmstate_indexes, cpu->cpreg_indexes,
- cpu->cpreg_array_len * sizeof(uint64_t));
- memcpy(cpu->cpreg_vmstate_values, cpu->cpreg_values,
- cpu->cpreg_array_len * sizeof(uint64_t));
return 0;
}
@@ -1001,6 +1005,9 @@ static int cpu_post_save(void *opaque)
pmu_op_finish(&cpu->env);
}
+ cpu->cpreg_vmstate_indexes = NULL;
+ cpu->cpreg_vmstate_values = NULL;
+
return 0;
}
@@ -1034,6 +1041,9 @@ static int cpu_pre_load(void *opaque)
pmu_op_start(env);
}
+ g_assert(!cpu->cpreg_vmstate_indexes);
+ g_assert(!cpu->cpreg_vmstate_values);
+
return 0;
}
@@ -1043,6 +1053,9 @@ static int cpu_post_load(void *opaque, int version_id)
CPUARMState *env = &cpu->env;
int i, v;
+ trace_cpu_post_load(cpu->cpreg_vmstate_array_len,
+ cpu->cpreg_array_len);
+
/*
* Handle migration compatibility from old QEMU which didn't
* send the irq-line-state subsection. A QEMU without it did not
@@ -1094,6 +1107,11 @@ static int cpu_post_load(void *opaque, int version_id)
}
}
+ g_free(cpu->cpreg_vmstate_indexes);
+ g_free(cpu->cpreg_vmstate_values);
+ cpu->cpreg_vmstate_indexes = NULL;
+ cpu->cpreg_vmstate_values = NULL;
+
/*
* Misaligned thumb pc is architecturally impossible. Fail the
* incoming migration. For TCG it would trigger the assert in
@@ -1167,16 +1185,17 @@ const VMStateDescription vmstate_arm_cpu = {
VMSTATE_UINT32_ARRAY(env.fiq_regs, ARMCPU, 5),
VMSTATE_UINT64_ARRAY(env.elr_el, ARMCPU, 4),
VMSTATE_UINT64_ARRAY(env.sp_el, ARMCPU, 4),
- /* The length-check must come before the arrays to avoid
- * incoming data possibly overflowing the array.
+ /*
+ * The length must come before the arrays so we can
+ * allocate the arrays before their data arrives
*/
- VMSTATE_INT32_POSITIVE_LE(cpreg_vmstate_array_len, ARMCPU),
- VMSTATE_VARRAY_INT32(cpreg_vmstate_indexes, ARMCPU,
- cpreg_vmstate_array_len,
- 0, vmstate_info_uint64, uint64_t),
- VMSTATE_VARRAY_INT32(cpreg_vmstate_values, ARMCPU,
- cpreg_vmstate_array_len,
- 0, vmstate_info_uint64, uint64_t),
+ VMSTATE_INT32(cpreg_vmstate_array_len, ARMCPU),
+ VMSTATE_VARRAY_INT32_ALLOC(cpreg_vmstate_indexes, ARMCPU,
+ cpreg_vmstate_array_len,
+ 0, vmstate_info_uint64, uint64_t),
+ VMSTATE_VARRAY_INT32_ALLOC(cpreg_vmstate_values, ARMCPU,
+ cpreg_vmstate_array_len,
+ 0, vmstate_info_uint64, uint64_t),
VMSTATE_UINT64(env.exclusive_addr, ARMCPU),
VMSTATE_UINT64(env.exclusive_val, ARMCPU),
VMSTATE_UINT64(env.exclusive_high, ARMCPU),
diff --git a/target/arm/trace-events b/target/arm/trace-events
index 676d29fe51..2de0406f78 100644
--- a/target/arm/trace-events
+++ b/target/arm/trace-events
@@ -26,3 +26,6 @@ arm_powerctl_reset_cpu(uint64_t mp_aff) "cpu %" PRIu64
# tcg/psci.c and hvf/hvf.c
arm_psci_call(uint64_t x0, uint64_t x1, uint64_t x2, uint64_t x3, uint32_t cpuid) "PSCI Call x0=0x%016"PRIx64" x1=0x%016"PRIx64" x2=0x%016"PRIx64" x3=0x%016"PRIx64" cpuid=0x%x"
+
+# machine.c
+cpu_post_load(uint32_t cpreg_vmstate_array_len, uint32_t cpreg_array_len) "cpreg_vmstate_array_len=%d cpreg_array_len=%d"
diff --git a/target/arm/whpx/whpx-all.c b/target/arm/whpx/whpx-all.c
index bb94eac7bf..c5b108166a 100644
--- a/target/arm/whpx/whpx-all.c
+++ b/target/arm/whpx/whpx-all.c
@@ -783,12 +783,6 @@ int whpx_init_vcpu(CPUState *cpu)
sregs_match_len);
arm_cpu->cpreg_values = g_renew(uint64_t, arm_cpu->cpreg_values,
sregs_match_len);
- arm_cpu->cpreg_vmstate_indexes = g_renew(uint64_t,
- arm_cpu->cpreg_vmstate_indexes,
- sregs_match_len);
- arm_cpu->cpreg_vmstate_values = g_renew(uint64_t,
- arm_cpu->cpreg_vmstate_values,
- sregs_match_len);
memset(arm_cpu->cpreg_values, 0, sregs_match_len * sizeof(uint64_t));
@@ -807,7 +801,6 @@ int whpx_init_vcpu(CPUState *cpu)
}
}
arm_cpu->cpreg_array_len = sregs_cnt;
- arm_cpu->cpreg_vmstate_array_len = sregs_cnt;
assert(write_cpustate_to_list(arm_cpu, false));