From b27fcb288bbdb9e2d89ce9ee578a8869f14c579c Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 8 Aug 2023 14:19:58 +1000 Subject: [PATCH] spapr: Fix record-replay machine reset consuming too many events MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Nicholas Piggin Signed-off-by: Cédric Le Goater --- hw/ppc/spapr.c | 12 +++++++++--- include/hw/ppc/spapr.h | 1 + 2 files changed, 10 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); diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index f47e8419a5..f4bd204d86 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -204,6 +204,7 @@ struct SpaprMachineState { uint32_t fdt_size; uint32_t fdt_initial_size; void *fdt_blob; + uint8_t fdt_rng_seed[32]; long kernel_size; bool kernel_le; uint64_t kernel_addr; -- 2.11.0