On 4/4/20 11:44 PM, Nathan Chancellor wrote:
> Hi Cédric,
>
> On Sat, Apr 04, 2020 at 05:36:55PM +0200, Cédric Le Goater wrote:
>> Commit e2392d4395dd ("ppc/pnv: Create BMC devices at machine init")
>> introduced default BMC devices which can be a problem when the same
>> devices are defined on the command line with :
>>
>> -device ipmi-bmc-sim,id=bmc0 -device isa-ipmi-bt,bmc=bmc0,irq=10
>>
>> QEMU fails with :
>>
>> qemu-system-ppc64: error creating device tree: node: FDT_ERR_EXISTS
>>
>> Use defaults_enabled() when creating the default BMC devices to let
>> the user provide its own BMC devices using '-nodefaults'. If no BMC
>> device are provided, output a warning but let QEMU run as this is a
>> supported configuration. However, when multiple BMC devices are
>> defined, stop QEMU with a clear error as the results are unexpected.
>>
>> Fixes: e2392d4395dd ("ppc/pnv: Create BMC devices at machine init")
>> Reported-by: Nathan Chancellor <natechancel...@gmail.com>
>> Signed-off-by: Cédric Le Goater <c...@kaod.org>
>
> This fixes my issue when -nodefaults is passed and that does not regress
> QEMU 3.1.0 or 4.2.0. Thank you for the quick fix!
>
> Tested-by: Nathan Chancellor <natechancel...@gmail.com>
>
> A few comments inline.
>
>> ---
>> include/hw/ppc/pnv.h | 2 ++
>> hw/ppc/pnv.c | 32 ++++++++++++++++++++++++++-----
>> hw/ppc/pnv_bmc.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 74 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/hw/ppc/pnv.h b/include/hw/ppc/pnv.h
>> index fb4d0c0234b3..d4b0b0e2ff71 100644
>> --- a/include/hw/ppc/pnv.h
>> +++ b/include/hw/ppc/pnv.h
>> @@ -241,6 +241,8 @@ struct PnvMachineState {
>> void pnv_dt_bmc_sensors(IPMIBmc *bmc, void *fdt);
>> void pnv_bmc_powerdown(IPMIBmc *bmc);
>> IPMIBmc *pnv_bmc_create(PnvPnor *pnor);
>> +IPMIBmc *pnv_bmc_find(Error **errp);
>> +void pnv_bmc_set_pnor(IPMIBmc *bmc, PnvPnor *pnor);
>>
>> /*
>> * POWER8 MMIO base addresses
>> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
>> index ac83b8698b8e..a3b7a8d0ff32 100644
>> --- a/hw/ppc/pnv.c
>> +++ b/hw/ppc/pnv.c
>> @@ -573,10 +573,29 @@ static void pnv_powerdown_notify(Notifier *n, void
>> *opaque)
>>
>> static void pnv_reset(MachineState *machine)
>> {
>> + PnvMachineState *pnv = PNV_MACHINE(machine);
>> + IPMIBmc *bmc;
>> void *fdt;
>>
>> qemu_devices_reset();
>>
>> + /*
>> + * The machine should provide by default an internal BMC simulator.
>> + * If not, try to use the BMC device that was provided on the command
>> + * line.
>> + */
>> + bmc = pnv_bmc_find(&error_fatal);
>> + if (!pnv->bmc) {
>> + if (!bmc) {
>> + warn_report("machine has no BMC device. Use '-device "
>> + "ipmi-bmc-sim,id=bmc0 -device
>> isa-ipmi-bt,bmc=bmc0,irq=10' "
>> + "to define one");
>
> If I pass no -device flags + -nodefaults, I don't see this message. Is
> that expected?
yes. Because the machine instantiates the default BMC devices.
>
>> + } else {
>> + pnv_bmc_set_pnor(bmc, pnv->pnor);
>> + pnv->bmc = bmc;
>> + }
>> + }
>> +
>> fdt = pnv_dt_create(machine);
>>
>> /* Pack resulting tree */
>> @@ -835,9 +854,6 @@ static void pnv_init(MachineState *machine)
>> }
>> g_free(chip_typename);
>>
>> - /* Create the machine BMC simulator */
>> - pnv->bmc = pnv_bmc_create(pnv->pnor);
>> -
>> /* Instantiate ISA bus on chip 0 */
>> pnv->isa_bus = pnv_isa_create(pnv->chips[0], &error_fatal);
>>
>> @@ -847,8 +863,14 @@ static void pnv_init(MachineState *machine)
>> /* Create an RTC ISA device too */
>> mc146818_rtc_init(pnv->isa_bus, 2000, NULL);
>>
>> - /* Create the IPMI BT device for communication with the BMC */
>> - pnv_ipmi_bt_init(pnv->isa_bus, pnv->bmc, 10);
>> + /*
>> + * Create the machine BMC simulator and the IPMI BT device for
>> + * communication with the BMC
>> + */
>> + if (defaults_enabled()) {
>> + pnv->bmc = pnv_bmc_create(pnv->pnor);
>> + pnv_ipmi_bt_init(pnv->isa_bus, pnv->bmc, 10);
>> + }
>>
>> /*
>> * OpenPOWER systems use a IPMI SEL Event message to notify the
>> diff --git a/hw/ppc/pnv_bmc.c b/hw/ppc/pnv_bmc.c
>> index 8863354c1c08..4e018b8b70e4 100644
>> --- a/hw/ppc/pnv_bmc.c
>> +++ b/hw/ppc/pnv_bmc.c
>> @@ -213,6 +213,18 @@ static const IPMINetfn hiomap_netfn = {
>> .cmd_handlers = hiomap_cmds
>> };
>>
>> +
>> +void pnv_bmc_set_pnor(IPMIBmc *bmc, PnvPnor *pnor)
>> +{
>> + object_ref(OBJECT(pnor));
>> + object_property_add_const_link(OBJECT(bmc), "pnor", OBJECT(pnor),
>> + &error_abort);
>> +
>> + /* Install the HIOMAP protocol handlers to access the PNOR */
>> + ipmi_sim_register_netfn(IPMI_BMC_SIMULATOR(bmc), IPMI_NETFN_OEM,
>> + &hiomap_netfn);
>> +}
>> +
>> /*
>> * Instantiate the machine BMC. PowerNV uses the QEMU internal
>> * simulator but it could also be external.
>> @@ -232,3 +244,36 @@ IPMIBmc *pnv_bmc_create(PnvPnor *pnor)
>>
>> return IPMI_BMC(obj);
>> }
>> +
>> +typedef struct ForeachArgs {
>> + const char *name;
>> + Object *obj;
>> +} ForeachArgs;
>> +
>> +static int bmc_find(Object *child, void *opaque)
>> +{
>> + ForeachArgs *args = opaque;
>> +
>> + if (object_dynamic_cast(child, args->name)) {
>> + if (args->obj) {
>> + return 1;
>> + }
>> + args->obj = child;
>> + }
>> + return 0;
>> +}
>> +
>> +IPMIBmc *pnv_bmc_find(Error **errp)
>> +{
>> + ForeachArgs args = { TYPE_IPMI_BMC_SIMULATOR, NULL };
>> + int ret;
>> +
>> + ret = object_child_foreach_recursive(object_get_root(), bmc_find,
>> &args);
>> + if (ret) {
>> + error_setg(errp, "machine should have only one BMC device. "
>> + "Use '-nodefaults'");
>
> When passing the -device flags in the commit message as I did in my
> original command without -nodefaults, I still see the
>
> qemu-system-ppc64: error creating device tree: node: FDT_ERR_EXISTS
>
> message. Is that expected?
object_child_foreach_recursive() is broken. Here is the fix :
http://patchwork.ozlabs.org/patch/1266419/
Sorry. I should have copied you.
But there are other ways to find multiple instances of the same type.
May be we will need to rework that part a bit.
Thanks,
C.
>
>> + return NULL;
>> + }
>> +
>> + return args.obj ? IPMI_BMC(args.obj) : NULL;
>> +}
>> --
>> 2.25.1
>>
