[v4,06/11] m68k/virt: do not re-randomize RNG seed on snapshot load

Commit Message

Jason A. Donenfeld Oct. 25, 2022, 12:43 a.m. UTC

Snapshot loading is supposed to be deterministic, so we shouldn't
re-randomize the various seeds used.

Signed-off-by: Jason A. Donenfeld <[e-mail]>
---
 hw/m68k/virt.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

Patch

diff --git a/hw/m68k/virt.c b/hw/m68k/virt.c
index 89c4108eb5..da5eafd275 100644
--- a/hw/m68k/virt.c
+++ b/hw/m68k/virt.c
@@ -89,7 +89,6 @@  typedef struct {
     M68kCPU *cpu;
     hwaddr initial_pc;
     hwaddr initial_stack;
-    struct bi_record *rng_seed;
 } ResetInfo;
 
 static void main_cpu_reset(void *opaque)
@@ -98,16 +97,18 @@  static void main_cpu_reset(void *opaque)
     M68kCPU *cpu = reset_info->cpu;
     CPUState *cs = CPU(cpu);
 
-    if (reset_info->rng_seed) {
-        qemu_guest_getrandom_nofail((void *)reset_info->rng_seed->data + 2,
-            be16_to_cpu(*(uint16_t *)reset_info->rng_seed->data));
-    }
-
     cpu_reset(cs);
     cpu->env.aregs[7] = reset_info->initial_stack;
     cpu->env.pc = reset_info->initial_pc;
 }
 
+static void rerandomize_rng_seed(void *opaque)
+{
+    struct bi_record *rng_seed = opaque;
+    qemu_guest_getrandom_nofail((void *)rng_seed->data + 2,
+                                be16_to_cpu(*(uint16_t *)rng_seed->data));
+}
+
 static void virt_init(MachineState *machine)
 {
     M68kCPU *cpu = NULL;
@@ -289,9 +290,10 @@  static void virt_init(MachineState *machine)
         BOOTINFO0(param_ptr, BI_LAST);
         rom_add_blob_fixed_as("bootinfo", param_blob, param_ptr - param_blob,
                               parameters_base, cs->as);
-        reset_info->rng_seed = rom_ptr_for_as(cs->as, parameters_base,
-                                              param_ptr - param_blob) +
-                               (param_rng_seed - param_blob);
+        qemu_register_reset_nosnapshotload(rerandomize_rng_seed,
+                            rom_ptr_for_as(cs->as, parameters_base,
+                                           param_ptr - param_blob) +
+                            (param_rng_seed - param_blob));
         g_free(param_blob);
     }
 }