Re: [Qemu-devel] [RFC] ppc: qdev-ify CPU creation

["Hervé Poussineau" <hpoussin@reactos.org>]

Alexander Graf a écrit :
> On 21.12.2010, at 21:01, Andreas Färber wrote:
>
>   
>> From: Hervé Poussineau <hpoussin@reactos.org>
>>
>> v1:
>> * Coding style fixes.
>>
>> Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
>> Cc: Alexander Graf <agraf@suse.de>
>> Signed-off-by: Andreas Färber <andreas.faerber@web.de>
>> ---
>>
>> Hello Alex,
>>
>> Seeing the discussions about Leon3, is this the way to go for ppc? Is ppc.[hc] right?
>>
>> The unconditional use of 6xx looks suspicious to me, no?
>> Should we rename cpu_device_irq_request() to cpu_device_irq_request_6xx()?
>>
>> Regards,
>> Andreas
>>
>> hw/ppc.c            |   75 +++++++++++++++++++++++++++++++++++++++++++++++++++
>> hw/ppc.h            |    2 +
>> target-ppc/cpu.h    |    1 +
>> target-ppc/helper.c |   21 +++++++++++---
>> 4 files changed, 94 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/ppc.c b/hw/ppc.c
>> index 968aec1..0927326 100644
>> --- a/hw/ppc.c
>> +++ b/hw/ppc.c
>> @@ -30,6 +30,8 @@
>> #include "loader.h"
>> #include "kvm.h"
>> #include "kvm_ppc.h"
>> +#include "hw/qdev.h"
>> +#include "hw/sysbus.h"
>>
>> //#define PPC_DEBUG_IRQ
>> //#define PPC_DEBUG_TB
>> @@ -1286,3 +1288,76 @@ int PPC_NVRAM_set_params (nvram_t *nvram, uint16_t NVRAM_size,
>>
>>     return 0;
>> }
>> +
>> +DeviceState *cpu_ppc_create_simple(const char *cpu_model)
>> +{
>> +    DeviceState *dev;
>> +
>> +    dev = qdev_create(NULL, "cpu-ppc");
>> +    if (!dev) {
>> +        return NULL;
>> +    }
>> +    qdev_prop_set_string(dev, "model", qemu_strdup(cpu_model));
>> +    if (qdev_init(dev) < 0) {
>> +        return NULL;
>> +    }
>> +    return dev;
>> +}
>> +
>> +typedef struct CPUPPC {
>> +    SysBusDevice busdev;
>>     
>
> I'm not sure we really want CPUs on the sysbus. They belong to their own CPU bus. Basically, I think we should try to model our bus topology so that it reflects the bus topology in the device tree 1:1. Then generating a device tree from the bug information and some device specific callbacks would be possible.
>
>   
CPUs don't need a bus with specific capabilities, so I used the most 
simple existing one, ie SysBus.
>> +    char *model;
>> +    CPUPPCState state;
>> +} CPUPPC;
>> +
>> +static void cpu_device_irq_request(void *opaque, int pin, int level)
>> +{
>> +    CPUPPC* cpu = opaque;
>> +    CPUPPCState* env = &cpu->state;
>> +    ppc6xx_set_irq(env, pin, level);
>> +}
>> +
>> +static int cpu_device_init(SysBusDevice *dev)
>> +{
>> +    CPUPPC* cpu = FROM_SYSBUS(CPUPPC, dev);
>> +    CPUPPCState* env = &cpu->state;
>> +
>> +    if (cpu_ppc_init_inplace(env, cpu->model) < 0) {
>> +        return -1;
>> +    }
>> +
>> +    if (env->flags & POWERPC_FLAG_RTC_CLK) {
>>     
>
> Where does this flag suddenly come from? Is this related to qdev'ification?
>
>   
It's not related to qdev'ification. It is already set in CPU definitions 
since a long time.

>> +        /* POWER / PowerPC 601 RTC clock frequency is 7.8125 MHz */
>> +        cpu_ppc_tb_init(env, 7812500UL);
>> +    } else {
>> +        /* Set time-base frequency to 100 Mhz */
>> +        cpu_ppc_tb_init(env, 100UL * 1000UL * 1000UL);
>>     
>
> Usually we have a TB frequency of 400Mhz in our board/devtrees hardcoded in the TCG case. How about a qdev property that the creator could just modify to its needs? We won't need the special 601 flag then either - just move that into the PREP code.
>
>   
This code has been extracted from ppc_prep.c ; a qdev property is also 
fine.
>> +    }
>> +
>> +    qdev_init_gpio_in(&dev->qdev, cpu_device_irq_request, PPC6xx_INPUT_NB);
>> +    return 0;
>> +}
>> +
>> +static void cpu_device_reset(DeviceState *d)
>> +{
>> +    CPUPPC *s = FROM_SYSBUS(CPUPPC, sysbus_from_qdev(d));
>> +    cpu_reset(&s->state);
>> +}
>> +
>> +static SysBusDeviceInfo cpu_device_info = {
>> +    .qdev.name = "cpu-ppc",
>> +    .qdev.size = sizeof(CPUPPC),
>> +    .qdev.reset = cpu_device_reset,
>> +    .init = cpu_device_init,
>> +    .qdev.props = (Property[]) {
>> +        DEFINE_PROP_STRING("model", CPUPPC, model),
>> +        DEFINE_PROP_END_OF_LIST(),
>> +    },
>> +};
>> +
>> +static void ppc_register_devices(void)
>> +{
>> +    sysbus_register_withprop(&cpu_device_info);
>> +}
>> +
>> +device_init(ppc_register_devices)
>> diff --git a/hw/ppc.h b/hw/ppc.h
>> index 34f54cf..ae8dd97 100644
>> --- a/hw/ppc.h
>> +++ b/hw/ppc.h
>> @@ -37,6 +37,8 @@ void ppce500_irq_init (CPUState *env);
>> void ppc6xx_irq_init (CPUState *env);
>> void ppc970_irq_init (CPUState *env);
>>
>> +DeviceState *cpu_ppc_create_simple(const char *cpu_model);
>> +
>> /* PPC machines for OpenBIOS */
>> enum {
>>     ARCH_PREP = 0,
>> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
>> index deb8d7c..0f56d45 100644
>> --- a/target-ppc/cpu.h
>> +++ b/target-ppc/cpu.h
>> @@ -721,6 +721,7 @@ struct mmu_ctx_t {
>>
>> /*****************************************************************************/
>> CPUPPCState *cpu_ppc_init (const char *cpu_model);
>> +int cpu_ppc_init_inplace(CPUPPCState *env, const char *cpu_model);
>> void ppc_translate_init(void);
>> int cpu_ppc_exec (CPUPPCState *s);
>> void cpu_ppc_close (CPUPPCState *s);
>> diff --git a/target-ppc/helper.c b/target-ppc/helper.c
>> index 4b49101..99af1f6 100644
>> --- a/target-ppc/helper.c
>> +++ b/target-ppc/helper.c
>> @@ -2794,22 +2794,33 @@ void cpu_reset(CPUPPCState *env)
>>     tlb_flush(env, 1);
>> }
>>
>> -CPUPPCState *cpu_ppc_init (const char *cpu_model)
>> +int cpu_ppc_init_inplace(CPUPPCState *env, const char *cpu_model)
>> {
>> -    CPUPPCState *env;
>>     const ppc_def_t *def;
>>
>>     def = cpu_ppc_find_by_name(cpu_model);
>> -    if (!def)
>> -        return NULL;
>> +    if (!def) {
>> +        return -1;
>> +    }
>>
>> -    env = qemu_mallocz(sizeof(CPUPPCState));
>>     cpu_exec_init(env);
>>     ppc_translate_init();
>>     env->cpu_model_str = cpu_model;
>>     cpu_ppc_register_internal(env, def);
>>
>>     qemu_init_vcpu(env);
>> +    return 0;
>> +}
>> +
>> +CPUPPCState *cpu_ppc_init(const char *cpu_model)
>> +{
>> +    CPUPPCState *env;
>> +
>> +    env = qemu_mallocz(sizeof(CPUPPCState));
>> +    if (cpu_ppc_init_inplace(env, cpu_model) < 0) {
>>     
>
> Why would we need this function again if the CPUs are qdev'ified?
>   
This function is not added ; it is already an existing one (see 25 lines 
before). I kept it to not put in the same patch the CPU qdev'ification 
and the change of all the callers.
Indeed, a second patch may be created to change all callers to use 
cpu_ppc_create_simple() and to remove this function.

> Overall, I really like the idea of moving CPUs to qdev though. Makes things a lot more structured.
>   
Thanks

Hervé