Re: [PATCH v2 6/6] hw/isa/piix: Resolve redundant TYPE_PIIX3_XEN_DEVICE

[Bernhard Beschow <shentey@xxxxxxxxx>]

Am 4. Januar 2023 15:35:33 UTC schrieb "Philippe Mathieu-Daudé" 
<philmd@xxxxxxxxxx>:
>+Markus/Thomas
>
>On 4/1/23 15:44, Bernhard Beschow wrote:
>> During the last patches, TYPE_PIIX3_XEN_DEVICE turned into a clone of
>> TYPE_PIIX3_DEVICE. Remove this redundancy.
>> 
>> Signed-off-by: Bernhard Beschow <shentey@xxxxxxxxx>
>> ---
>>   hw/i386/pc_piix.c             |  4 +---
>>   hw/isa/piix.c                 | 20 --------------------
>>   include/hw/southbridge/piix.h |  1 -
>>   3 files changed, 1 insertion(+), 24 deletions(-)
>> 
>> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>> index 5738d9cdca..6b8de3d59d 100644
>> --- a/hw/i386/pc_piix.c
>> +++ b/hw/i386/pc_piix.c
>> @@ -235,8 +235,6 @@ static void pc_init1(MachineState *machine,
>>       if (pcmc->pci_enabled) {
>>           DeviceState *dev;
>>           PCIDevice *pci_dev;
>> -        const char *type = xen_enabled() ? TYPE_PIIX3_XEN_DEVICE
>> -                                         : TYPE_PIIX3_DEVICE;
>>           int i;
>>             pci_bus = i440fx_init(pci_type,
>> @@ -250,7 +248,7 @@ static void pc_init1(MachineState *machine,
>>                                          : pci_slot_get_pirq);
>>           pcms->bus = pci_bus;
>>   -        pci_dev = pci_new_multifunction(-1, true, type);
>> +        pci_dev = pci_new_multifunction(-1, true, TYPE_PIIX3_DEVICE);
>>           object_property_set_bool(OBJECT(pci_dev), "has-usb",
>>                                    machine_usb(machine), &error_abort);
>>           object_property_set_bool(OBJECT(pci_dev), "has-acpi",
>> diff --git a/hw/isa/piix.c b/hw/isa/piix.c
>> index 98e9b12661..e4587352c9 100644
>> --- a/hw/isa/piix.c
>> +++ b/hw/isa/piix.c
>> @@ -33,7 +33,6 @@
>>   #include "hw/qdev-properties.h"
>>   #include "hw/ide/piix.h"
>>   #include "hw/isa/isa.h"
>> -#include "hw/xen/xen.h"
>>   #include "sysemu/runstate.h"
>>   #include "migration/vmstate.h"
>>   #include "hw/acpi/acpi_aml_interface.h"
>> @@ -465,24 +464,6 @@ static const TypeInfo piix3_info = {
>>       .class_init    = piix3_class_init,
>>   };
>>   -static void piix3_xen_class_init(ObjectClass *klass, void *data)
>> -{
>> -    DeviceClass *dc = DEVICE_CLASS(klass);
>> -    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
>> -
>> -    k->realize = piix3_realize;
>> -    /* 82371SB PIIX3 PCI-to-ISA bridge (Step A1) */
>> -    k->device_id = PCI_DEVICE_ID_INTEL_82371SB_0;
>> -    dc->vmsd = &vmstate_piix3;
>
>IIUC, since this device is user-creatable, we can't simply remove it
>without going thru the deprecation process.

AFAICS this device is actually not user-creatable since dc->user_creatable is 
set to false once in the base class. I think it is safe to remove the Xen class 
unless there are ABI issues.

Best regards,
Bernhard

>Alternatively we could
>add a type alias:
>
>-- >8 --
>diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
>index 4b0ef65780..d94f7ea369 100644
>--- a/softmmu/qdev-monitor.c
>+++ b/softmmu/qdev-monitor.c
>@@ -64,6 +64,7 @@ typedef struct QDevAlias
>                               QEMU_ARCH_LOONGARCH)
> #define QEMU_ARCH_VIRTIO_CCW (QEMU_ARCH_S390X)
> #define QEMU_ARCH_VIRTIO_MMIO (QEMU_ARCH_M68K)
>+#define QEMU_ARCH_XEN (QEMU_ARCH_ARM | QEMU_ARCH_I386)
>
> /* Please keep this table sorted by typename. */
> static const QDevAlias qdev_alias_table[] = {
>@@ -111,6 +112,7 @@ static const QDevAlias qdev_alias_table[] = {
>     { "virtio-tablet-device", "virtio-tablet", QEMU_ARCH_VIRTIO_MMIO },
>     { "virtio-tablet-ccw", "virtio-tablet", QEMU_ARCH_VIRTIO_CCW },
>     { "virtio-tablet-pci", "virtio-tablet", QEMU_ARCH_VIRTIO_PCI },
>+    { "PIIX3", "PIIX3-xen", QEMU_ARCH_XEN },
>     { }
> };
>---
>
>But I'm not sure due to this comment from commit ee46d8a503
>(2011-12-22 15:24:20 -0600):
>
>47) /*
>48)  * Aliases were a bad idea from the start.  Let's keep them
>49)  * from spreading further.
>50)  */
>
>Maybe using qdev_alias_table[] during device deprecation is
>acceptable?
>
>> -}
>> -
>> -static const TypeInfo piix3_xen_info = {
>> -    .name          = TYPE_PIIX3_XEN_DEVICE,
>> -    .parent        = TYPE_PIIX_PCI_DEVICE,
>> -    .instance_init = piix3_init,
>> -    .class_init    = piix3_xen_class_init,
>> -};
>> -
>>   static void piix4_realize(PCIDevice *dev, Error **errp)
>>   {
>>       ERRP_GUARD();
>> @@ -534,7 +515,6 @@ static void piix3_register_types(void)
>>   {
>>       type_register_static(&piix_pci_type_info);
>>       type_register_static(&piix3_info);
>> -    type_register_static(&piix3_xen_info);
>>       type_register_static(&piix4_info);
>>   }
>>   diff --git a/include/hw/southbridge/piix.h b/include/hw/southbridge/piix.h
>> index 65ad8569da..b1fc94a742 100644
>> --- a/include/hw/southbridge/piix.h
>> +++ b/include/hw/southbridge/piix.h
>> @@ -77,7 +77,6 @@ struct PIIXState {
>>   OBJECT_DECLARE_SIMPLE_TYPE(PIIXState, PIIX_PCI_DEVICE)
>>     #define TYPE_PIIX3_DEVICE "PIIX3"
>> -#define TYPE_PIIX3_XEN_DEVICE "PIIX3-xen"
>>   #define TYPE_PIIX4_PCI_DEVICE "piix4-isa"
>>     #endif
>