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authorNicholas Piggin <npiggin@gmail.com>2023-08-08 14:19:58 +1000
committerCédric Le Goater <clg@kaod.org>2023-09-06 11:19:33 +0200
commitb27fcb288bbdb9e2d89ce9ee578a8869f14c579c (patch)
tree86e0d262b9b252c8cf2c882ee969b8c786a33483 /hw
parent9c7b7f01f982a22b06c0d2f49a0d2466b5f34485 (diff)
downloadfocaccia-qemu-b27fcb288bbdb9e2d89ce9ee578a8869f14c579c.tar.gz
focaccia-qemu-b27fcb288bbdb9e2d89ce9ee578a8869f14c579c.zip
spapr: Fix record-replay machine reset consuming too many events
spapr_machine_reset gets a random number to populate the device-tree
rng seed with. When loading a snapshot for record-replay, the machine
is reset again, and that tries to consume the random event record
again, crashing due to inconsistent record

Fix this by saving the seed to populate the device tree with, and
skipping the rng on snapshot load.

Acked-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Diffstat (limited to 'hw')
-rw-r--r--hw/ppc/spapr.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index c0b0ada121..f7cc6a890f 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1022,7 +1022,6 @@ static void spapr_dt_chosen(SpaprMachineState *spapr, void *fdt, bool reset)
 {
     MachineState *machine = MACHINE(spapr);
     SpaprMachineClass *smc = SPAPR_MACHINE_GET_CLASS(machine);
-    uint8_t rng_seed[32];
     int chosen;
 
     _FDT(chosen = fdt_add_subnode(fdt, 0, "chosen"));
@@ -1100,8 +1099,7 @@ static void spapr_dt_chosen(SpaprMachineState *spapr, void *fdt, bool reset)
         spapr_dt_ov5_platform_support(spapr, fdt, chosen);
     }
 
-    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
-    _FDT(fdt_setprop(fdt, chosen, "rng-seed", rng_seed, sizeof(rng_seed)));
+    _FDT(fdt_setprop(fdt, chosen, "rng-seed", spapr->fdt_rng_seed, 32));
 
     _FDT(spapr_dt_ovec(fdt, chosen, spapr->ov5_cas, "ibm,architecture-vec-5"));
 }
@@ -1654,6 +1652,14 @@ static void spapr_machine_reset(MachineState *machine, ShutdownCause reason)
     void *fdt;
     int rc;
 
+    if (reason != SHUTDOWN_CAUSE_SNAPSHOT_LOAD) {
+        /*
+         * Record-replay snapshot load must not consume random, this was
+         * already replayed from initial machine reset.
+         */
+        qemu_guest_getrandom_nofail(spapr->fdt_rng_seed, 32);
+    }
+
     pef_kvm_reset(machine->cgs, &error_fatal);
     spapr_caps_apply(spapr);