Re: [Qemu-devel] [v4][PATCH 3/5] I440FX_PCI_DEVICE: add pci_type to index

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 2014/8/7 5:07, Michael S. Tsirkin wrote:
> On Wed, Aug 06, 2014 at 06:17:02PM +0800, Chen, Tiejun wrote:
>> On 2014/8/6 17:45, Michael S. Tsirkin wrote:
>>> On Wed, Aug 06, 2014 at 02:50:33PM +0800, Tiejun Chen wrote:
>>>> We need to use this index to reuse this macro later
>>>>
>>>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
>>>
>>> Which index?
>>> Most users don't need to change.
>>> Just open-code OBJECT_CHECK where necessary, or add
>>> a new wrapper.
>>
>> Okay so what about this?
>>
>>      hw:pci-host:piix: define I440FX_PCI_DEVICE_FROM_TYPE
>>
>>      We need to introduce I440FX_PCI_DEVICE_FROM_TYPE to get
>>      object with type, then we can reuse i440fx_init() simply.
>>
>>      Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
>>
>> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
>> index 0cd82b8..8c74653 100644
>> --- a/hw/pci-host/piix.c
>> +++ b/hw/pci-host/piix.c
>> @@ -93,6 +93,9 @@ typedef struct PIIX3State {
>>   #define I440FX_PCI_DEVICE(obj) \
>>       OBJECT_CHECK(PCII440FXState, (obj), TYPE_I440FX_PCI_DEVICE)
>>
>> +#define I440FX_PCI_DEVICE_FROM_TYPE(obj, type) \
>> +    OBJECT_CHECK(PCII440FXState, (obj), type)
>
> This is just wrong. If you are casting to PCII440FXState,

Why? We will have two different QOM typenames of PCII440FXStates.

> there is no reason not to use TYPE_I440FX_PCI_DEVICE.

As you know we already have this original,

static const TypeInfo i440fx_info = {
     .name          = TYPE_I440FX_PCI_DEVICE,
     .parent        = TYPE_PCI_DEVICE,
     .instance_size = sizeof(PCII440FXState),
     .class_init    = i440fx_class_init,
};

and in patch #4, we will register that new host bridge to IGD passthrough:

static const TypeInfo xen_igd_passthrough_i440fx_info = {
     .name          = TYPE_XEN_IGD_PASSTHROUGH_I440FX_PCI_DEVICE,
     .parent        = TYPE_PCI_DEVICE,
     .instance_size = sizeof(PCII440FXState),
     .class_init    = xen_igd_passthrough_i440fx_class_init,
};

After that, we have two different QOM typenames of PCII440FXStates, 
TYPE_I440FX_PCI_DEVICE and TYPE_XEN_IGD_PASSTHROUGH_I440FX_PCI_DEVICE, 
right? So if you think we still should use this original,

#define I440FX_PCI_DEVICE(obj) \
	OBJECT_CHECK(PCII440FXState, (obj), TYPE_I440FX_PCI_DEVICE)

I really don't understand how to distinguish TYPE_I440FX_PCI_DEVICE and 
TYPE_XEN_IGD_PASSTHROUGH_I440FX_PCI_DEVICE just with I440FX_PCI_DEVICE(obj).

This should involve two places:

#1: static int i440fx_initfn(PCIDevice *dev)
{
     PCII440FXState *d = I440FX_PCI_DEVICE(dev);
     ...

#2: PCIBus *i440fx_init(const char *host_type, const char *pci_type,
                     PCII440FXState **pi440fx_state,
                     int *piix3_devfn,
                     ISABus **isa_bus, qemu_irq *pic,
                     MemoryRegion *address_space_mem,
                     MemoryRegion *address_space_io,
                     ram_addr_t ram_size,
                     ram_addr_t below_4g_mem_size,
                     ram_addr_t above_4g_mem_size,
                     MemoryRegion *pci_address_space,
                     MemoryRegion *ram_memory)
{
     ...
     PCIDevice *d;
     ...
     *pi440fx_state = I440FX_PCI_DEVICE(d);
     ...

So if you think I'm wrong please show me how to do just with 
I440FX_PCI_DEVICE() to work all scenarios from your point of view, then 
I'd like to followup yours to validate.

Thanks
Tiejun

>
>> +
>>   struct PCII440FXState {
>>       /*< private >*/
>>       PCIDevice parent_obj;
>> @@ -333,7 +336,7 @@ PCIBus *i440fx_init(const char *host_type, const char
>> *pci_type,
>>       qdev_init_nofail(dev);
>>
>>       d = pci_create_simple(b, 0, pci_type);
>> -    *pi440fx_state = I440FX_PCI_DEVICE(d);
>> +    *pi440fx_state = I440FX_PCI_DEVICE_FROM_TYPE(d, pci_type);
>>       f = *pi440fx_state;
>>       f->system_memory = address_space_mem;
>>       f->pci_address_space = pci_address_space;
>>
>>
>> Thanks
>> Tiejun
>>
>>>
>>>> ---
>>>>   hw/pci-host/piix.c | 10 +++++-----
>>>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>>>
>>>> v4:
>>>>
>>>> * New patch to extend I440FX_PCI_DEVICE
>>>>
>>>> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
>>>> index 0cd82b8..4330599 100644
>>>> --- a/hw/pci-host/piix.c
>>>> +++ b/hw/pci-host/piix.c
>>>> @@ -90,8 +90,8 @@ typedef struct PIIX3State {
>>>>       MemoryRegion rcr_mem;
>>>>   } PIIX3State;
>>>>
>>>> -#define I440FX_PCI_DEVICE(obj) \
>>>> -    OBJECT_CHECK(PCII440FXState, (obj), TYPE_I440FX_PCI_DEVICE)
>>>> +#define I440FX_PCI_DEVICE(obj, type) \
>>>> +    OBJECT_CHECK(PCII440FXState, (obj), type)
>>>>
>>>>   struct PCII440FXState {
>>>>       /*< private >*/
>>>> @@ -155,7 +155,7 @@ static void i440fx_set_smm(int val, void *arg)
>>>>   static void i440fx_write_config(PCIDevice *dev,
>>>>                                   uint32_t address, uint32_t val, int len)
>>>>   {
>>>> -    PCII440FXState *d = I440FX_PCI_DEVICE(dev);
>>>> +    PCII440FXState *d = I440FX_PCI_DEVICE(dev, TYPE_I440FX_PCI_DEVICE);
>>>>
>>>>       /* XXX: implement SMRAM.D_LOCK */
>>>>       pci_default_write_config(dev, address, val, len);
>>>> @@ -295,7 +295,7 @@ static void i440fx_pcihost_realize(DeviceState *dev, Error **errp)
>>>>
>>>>   static int i440fx_initfn(PCIDevice *dev)
>>>>   {
>>>> -    PCII440FXState *d = I440FX_PCI_DEVICE(dev);
>>>> +    PCII440FXState *d = I440FX_PCI_DEVICE(dev, TYPE_I440FX_PCI_DEVICE);
>>>>
>>>>       dev->config[I440FX_SMRAM] = 0x02;
>>>>
>>>> @@ -333,7 +333,7 @@ PCIBus *i440fx_init(const char *host_type, const char *pci_type,
>>>>       qdev_init_nofail(dev);
>>>>
>>>>       d = pci_create_simple(b, 0, pci_type);
>>>> -    *pi440fx_state = I440FX_PCI_DEVICE(d);
>>>> +    *pi440fx_state = I440FX_PCI_DEVICE(d, pci_type);
>>>>       f = *pi440fx_state;
>>>>       f->system_memory = address_space_mem;
>>>>       f->pci_address_space = pci_address_space;
>>>> --
>>>> 1.9.1
>>>
>>>
>