diff mbox series

[v4,1/9] hw/pci-host/i440fx: Inline sysbus_add_io()

Message ID 20230213162004.2797-2-shentey@gmail.com
State New
Headers show
Series PC cleanups | expand

Commit Message

Bernhard Beschow Feb. 13, 2023, 4:19 p.m. UTC 
sysbus_add_io() just wraps memory_region_add_subregion() while also
obscuring where the memory is attached. So use
memory_region_add_subregion() directly and attach it to the existing
memory region s->bus->address_space_io which is set as an alias to
get_system_io() by the pc machine.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 hw/pci-host/i440fx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Philippe Mathieu-Daudé Feb. 22, 2023, 10:58 a.m. UTC | #1 
On 13/2/23 17:19, Bernhard Beschow wrote:
> sysbus_add_io() just wraps memory_region_add_subregion() while also
> obscuring where the memory is attached. So use
> memory_region_add_subregion() directly and attach it to the existing
> memory region s->bus->address_space_io which is set as an alias to
> get_system_io() by the pc machine.
> 
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> ---
>   hw/pci-host/i440fx.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
> index 262f82c303..9c6882d3fc 100644
> --- a/hw/pci-host/i440fx.c
> +++ b/hw/pci-host/i440fx.c
> @@ -27,6 +27,7 @@
>   #include "qemu/range.h"
>   #include "hw/i386/pc.h"
>   #include "hw/pci/pci.h"
> +#include "hw/pci/pci_bus.h"
>   #include "hw/pci/pci_host.h"
>   #include "hw/pci-host/i440fx.h"
>   #include "hw/qdev-properties.h"
> @@ -217,10 +218,10 @@ static void i440fx_pcihost_realize(DeviceState *dev, Error **errp)
>       PCIHostState *s = PCI_HOST_BRIDGE(dev);
>       SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
>   
> -    sysbus_add_io(sbd, 0xcf8, &s->conf_mem);
> +    memory_region_add_subregion(s->bus->address_space_io, 0xcf8, &s->conf_mem);

To avoid accessing internal fields we should stick to the PCI API:

     memory_region_add_subregion(pci_address_space_io(PCI_DEVICE(dev)),
                                 0xcf8, &s->conf_mem);

>       sysbus_init_ioports(sbd, 0xcf8, 4);
>   
> -    sysbus_add_io(sbd, 0xcfc, &s->data_mem);
> +    memory_region_add_subregion(s->bus->address_space_io, 0xcfc, &s->data_mem);
>       sysbus_init_ioports(sbd, 0xcfc, 4);

Now all classes implementing PCI_HOST_BRIDGE register conf/data in I/O
space, so this could be a pattern justifying reworking a bit the
PCIHostBridgeClass or adding an helper in "hw/pci/pci_host.h" to do
that generically.
Bernhard Beschow Feb. 22, 2023, 6:05 p.m. UTC | #2 
Am 22. Februar 2023 10:58:08 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>On 13/2/23 17:19, Bernhard Beschow wrote:
>> sysbus_add_io() just wraps memory_region_add_subregion() while also
>> obscuring where the memory is attached. So use
>> memory_region_add_subregion() directly and attach it to the existing
>> memory region s->bus->address_space_io which is set as an alias to
>> get_system_io() by the pc machine.
>> 
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>> ---
>>   hw/pci-host/i440fx.c | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>> 
>> diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
>> index 262f82c303..9c6882d3fc 100644
>> --- a/hw/pci-host/i440fx.c
>> +++ b/hw/pci-host/i440fx.c
>> @@ -27,6 +27,7 @@
>>   #include "qemu/range.h"
>>   #include "hw/i386/pc.h"
>>   #include "hw/pci/pci.h"
>> +#include "hw/pci/pci_bus.h"
>>   #include "hw/pci/pci_host.h"
>>   #include "hw/pci-host/i440fx.h"
>>   #include "hw/qdev-properties.h"
>> @@ -217,10 +218,10 @@ static void i440fx_pcihost_realize(DeviceState *dev, Error **errp)
>>       PCIHostState *s = PCI_HOST_BRIDGE(dev);
>>       SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
>>   -    sysbus_add_io(sbd, 0xcf8, &s->conf_mem);
>> +    memory_region_add_subregion(s->bus->address_space_io, 0xcf8, &s->conf_mem);
>
>To avoid accessing internal fields we should stick to the PCI API:
>
>    memory_region_add_subregion(pci_address_space_io(PCI_DEVICE(dev)),
>                                0xcf8, &s->conf_mem);

dev is of type PCIHostState which derives from SysBusDevice, not PCIDevice. AFAICS there is no getter implemented on PCIBus.

>
>>       sysbus_init_ioports(sbd, 0xcf8, 4);
>>   -    sysbus_add_io(sbd, 0xcfc, &s->data_mem);
>> +    memory_region_add_subregion(s->bus->address_space_io, 0xcfc, &s->data_mem);
>>       sysbus_init_ioports(sbd, 0xcfc, 4);
>
>Now all classes implementing PCI_HOST_BRIDGE register conf/data in I/O
>space, so this could be a pattern justifying reworking a bit the
>PCIHostBridgeClass or adding an helper in "hw/pci/pci_host.h" to do
>that generically.

What do you mean exactly? There are PCI hosts spawning two PCI buses and therefore have two such spaces.

Best regards,
Bernhard
Bernhard Beschow March 6, 2023, 6:57 a.m. UTC | #3 
Am 22. Februar 2023 18:05:51 UTC schrieb Bernhard Beschow <shentey@gmail.com>:
>
>
>Am 22. Februar 2023 10:58:08 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>>On 13/2/23 17:19, Bernhard Beschow wrote:
>>> sysbus_add_io() just wraps memory_region_add_subregion() while also
>>> obscuring where the memory is attached. So use
>>> memory_region_add_subregion() directly and attach it to the existing
>>> memory region s->bus->address_space_io which is set as an alias to
>>> get_system_io() by the pc machine.
>>> 
>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>>> ---
>>>   hw/pci-host/i440fx.c | 5 +++--
>>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>> 
>>> diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
>>> index 262f82c303..9c6882d3fc 100644
>>> --- a/hw/pci-host/i440fx.c
>>> +++ b/hw/pci-host/i440fx.c
>>> @@ -27,6 +27,7 @@
>>>   #include "qemu/range.h"
>>>   #include "hw/i386/pc.h"
>>>   #include "hw/pci/pci.h"
>>> +#include "hw/pci/pci_bus.h"
>>>   #include "hw/pci/pci_host.h"
>>>   #include "hw/pci-host/i440fx.h"
>>>   #include "hw/qdev-properties.h"
>>> @@ -217,10 +218,10 @@ static void i440fx_pcihost_realize(DeviceState *dev, Error **errp)
>>>       PCIHostState *s = PCI_HOST_BRIDGE(dev);
>>>       SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
>>>   -    sysbus_add_io(sbd, 0xcf8, &s->conf_mem);
>>> +    memory_region_add_subregion(s->bus->address_space_io, 0xcf8, &s->conf_mem);
>>
>>To avoid accessing internal fields we should stick to the PCI API:
>>
>>    memory_region_add_subregion(pci_address_space_io(PCI_DEVICE(dev)),
>>                                0xcf8, &s->conf_mem);
>
>dev is of type PCIHostState which derives from SysBusDevice, not PCIDevice. AFAICS there is no getter implemented on PCIBus.

Ping

>
>>
>>>       sysbus_init_ioports(sbd, 0xcf8, 4);
>>>   -    sysbus_add_io(sbd, 0xcfc, &s->data_mem);
>>> +    memory_region_add_subregion(s->bus->address_space_io, 0xcfc, &s->data_mem);
>>>       sysbus_init_ioports(sbd, 0xcfc, 4);
>>
>>Now all classes implementing PCI_HOST_BRIDGE register conf/data in I/O
>>space, so this could be a pattern justifying reworking a bit the
>>PCIHostBridgeClass or adding an helper in "hw/pci/pci_host.h" to do
>>that generically.
>
>What do you mean exactly? There are PCI hosts spawning two PCI buses and therefore have two such spaces.
>
>Best regards,
>Bernhard
Philippe Mathieu-Daudé March 7, 2023, 10:32 p.m. UTC | #4 
On 6/3/23 07:57, Bernhard Beschow wrote:
> 
> 
> Am 22. Februar 2023 18:05:51 UTC schrieb Bernhard Beschow <shentey@gmail.com>:
>>
>>
>> Am 22. Februar 2023 10:58:08 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>>> On 13/2/23 17:19, Bernhard Beschow wrote:
>>>> sysbus_add_io() just wraps memory_region_add_subregion() while also
>>>> obscuring where the memory is attached. So use
>>>> memory_region_add_subregion() directly and attach it to the existing
>>>> memory region s->bus->address_space_io which is set as an alias to
>>>> get_system_io() by the pc machine.
>>>>
>>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>>>> ---
>>>>    hw/pci-host/i440fx.c | 5 +++--
>>>>    1 file changed, 3 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
>>>> index 262f82c303..9c6882d3fc 100644
>>>> --- a/hw/pci-host/i440fx.c
>>>> +++ b/hw/pci-host/i440fx.c
>>>> @@ -27,6 +27,7 @@
>>>>    #include "qemu/range.h"
>>>>    #include "hw/i386/pc.h"
>>>>    #include "hw/pci/pci.h"
>>>> +#include "hw/pci/pci_bus.h"
>>>>    #include "hw/pci/pci_host.h"
>>>>    #include "hw/pci-host/i440fx.h"
>>>>    #include "hw/qdev-properties.h"
>>>> @@ -217,10 +218,10 @@ static void i440fx_pcihost_realize(DeviceState *dev, Error **errp)
>>>>        PCIHostState *s = PCI_HOST_BRIDGE(dev);
>>>>        SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
>>>>    -    sysbus_add_io(sbd, 0xcf8, &s->conf_mem);
>>>> +    memory_region_add_subregion(s->bus->address_space_io, 0xcf8, &s->conf_mem);
>>>
>>> To avoid accessing internal fields we should stick to the PCI API:
>>>
>>>     memory_region_add_subregion(pci_address_space_io(PCI_DEVICE(dev)),
>>>                                 0xcf8, &s->conf_mem);
>>
>> dev is of type PCIHostState which derives from SysBusDevice, not PCIDevice. AFAICS there is no getter implemented on PCIBus.

You are right, there is no getter for PCIBus::address_space_io,
it is accessed directly:

   MemoryRegion *pci_address_space_io(PCIDevice *dev)
   {
       return pci_get_bus(dev)->address_space_io;
   }

If it is considered a property, probably no need for getter.

So:
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> 
>>
>>>
>>>>        sysbus_init_ioports(sbd, 0xcf8, 4);
>>>>    -    sysbus_add_io(sbd, 0xcfc, &s->data_mem);
>>>> +    memory_region_add_subregion(s->bus->address_space_io, 0xcfc, &s->data_mem);
>>>>        sysbus_init_ioports(sbd, 0xcfc, 4);
>>>
>>> Now all classes implementing PCI_HOST_BRIDGE register conf/data in I/O
>>> space, so this could be a pattern justifying reworking a bit the
>>> PCIHostBridgeClass or adding an helper in "hw/pci/pci_host.h" to do
>>> that generically.

(this comment is besides the scope of this patch)

>> What do you mean exactly? There are PCI hosts spawning two PCI buses and therefore have two such spaces.

I haven't checked but IIRC each PCI host exposing I/O registers
to access buses via ISA I/O open-code it. Even if it exposes
multiple buses, the same pattern is used (1 time per bus).

Anyway, no need to worry about that now...
diff mbox series

Patch

diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
index 262f82c303..9c6882d3fc 100644
--- a/hw/pci-host/i440fx.c
+++ b/hw/pci-host/i440fx.c
@@ -27,6 +27,7 @@ 
 #include "qemu/range.h"
 #include "hw/i386/pc.h"
 #include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
 #include "hw/pci/pci_host.h"
 #include "hw/pci-host/i440fx.h"
 #include "hw/qdev-properties.h"
@@ -217,10 +218,10 @@  static void i440fx_pcihost_realize(DeviceState *dev, Error **errp)
     PCIHostState *s = PCI_HOST_BRIDGE(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 
-    sysbus_add_io(sbd, 0xcf8, &s->conf_mem);
+    memory_region_add_subregion(s->bus->address_space_io, 0xcf8, &s->conf_mem);
     sysbus_init_ioports(sbd, 0xcf8, 4);
 
-    sysbus_add_io(sbd, 0xcfc, &s->data_mem);
+    memory_region_add_subregion(s->bus->address_space_io, 0xcfc, &s->data_mem);
     sysbus_init_ioports(sbd, 0xcfc, 4);
 
     /* register i440fx 0xcf8 port as coalesced pio */