Re: [Qemu-devel] [PATCH v2 06/11] memory: add ref/unref calls

[Jan Kiszka]

On 2013-07-02 10:18, Paolo Bonzini wrote:
> Il 02/07/2013 09:11, Jan Kiszka ha scritto:
>> On 2013-07-02 08:42, Paolo Bonzini wrote:
>>> Il 01/07/2013 20:33, Jan Kiszka ha scritto:
>>>> On 2013-06-28 18:58, Paolo Bonzini wrote:
>>>>> Add ref/unref calls at the following places:
>>>>>
>>>>> - places where memory regions are stashed by a listener and
>>>>>   used outside the BQL (including in Xen or KVM).
>>>>>
>>>>> - memory_region_find callsites
>>>>
>>>> You missed some recently added ones. Check hw/acpi/piix4.c and
>>>> hw/isa/lpc_ich9.c (both will require some refactorings for this).
>>>
>>> Here are the required changes:
>>>
>>> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
>>> index 3b95c69..0310053 100644
>>> --- a/hw/acpi/piix4.c
>>> +++ b/hw/acpi/piix4.c
>>> @@ -380,6 +380,16 @@ static void piix4_pm_powerdown_req(Notifier *n, void 
>>> *opaque)
>>>      acpi_pm1_evt_power_down(&s->ar);
>>>  }
>>>  
>>> +static bool memory_region_present(MemoryRegion *io, hwaddr port)
>>> +{
>>> +    MemoryRegion *mr = memory_region_find(io, port, 1);
>>> +    if (!mr) {
>>> +        return false;
>>> +    }
>>> +    memory_region_unref(mr);
>>> +    return true;
>>> +}
>>> +
>>>  static void piix4_pm_machine_ready(Notifier *n, void *opaque)
>>>  {
>>>      PIIX4PMState *s = container_of(n, PIIX4PMState, machine_ready);
>>> @@ -388,10 +398,10 @@ static void piix4_pm_machine_ready(Notifier *n, void 
>>> *opaque)
>>>  
>>>      pci_conf = s->dev.config;
>>>      pci_conf[0x5f] = 0x10 |
>>> -        (memory_region_find(io_as, 0x378, 1).mr ? 0x80 : 0);
>>> +        (memory_region_present(io_as, 0x378, 1) ? 0x80 : 0);
>>>      pci_conf[0x63] = 0x60;
>>> -    pci_conf[0x67] = (memory_region_find(io_as, 0x3f8, 1).mr ? 0x08 : 0) |
>>> -        (memory_region_find(io_as, 0x2f8, 1).mr ? 0x90 : 0);
>>> +    pci_conf[0x67] = (memory_region_present(io_as, 0x3f8, 1) ? 0x08 : 0) |
>>> +        (memory_region_present(io_as, 0x2f8, 1) ? 0x90 : 0);
>>>  }
>>>  
>>>  static int piix4_pm_initfn(PCIDevice *dev)
>>> diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
>>> index 82f8ea6..205ac26 100644
>>> --- a/hw/isa/lpc_ich9.c
>>> +++ b/hw/isa/lpc_ich9.c
>>> @@ -478,24 +478,33 @@ static void ich9_lpc_machine_ready(Notifier *n, void 
>>> *opaque)
>>>  {
>>>      ICH9LPCState *s = container_of(n, ICH9LPCState, machine_ready);
>>>      MemoryRegion *io_as = pci_address_space_io(&s->d);
>>> +    MemoryRegion *mr;
>>>      uint8_t *pci_conf;
>>>  
>>>      pci_conf = s->d.config;
>>> -    if (memory_region_find(io_as, 0x3f8, 1).mr) {
>>> +    mr = memory_region_find(io_as, 0x3f8, 1).mr;
>>> +    if (mr) {
>>>          /* com1 */
>>>          pci_conf[0x82] |= 0x01;
>>> +        memory_region_unref(mr);
>>>      }
>>> -    if (memory_region_find(io_as, 0x2f8, 1).mr) {
>>> +    mr = memory_region_find(io_as, 0x2f8, 1).mr;
>>> +    if (mr) {
>>>          /* com2 */
>>>          pci_conf[0x82] |= 0x02;
>>> +        memory_region_unref(mr);
>>>      }
>>> -    if (memory_region_find(io_as, 0x378, 1).mr) {
>>> +    mr = memory_region_find(io_as, 0x378, 1).mr;
>>> +    if (mr) {
>>>          /* lpt */
>>>          pci_conf[0x82] |= 0x04;
>>> +        memory_region_unref(mr);
>>>      }
>>> -    if (memory_region_find(io_as, 0x3f0, 1).mr) {
>>> +    mr = memory_region_find(io_as, 0x3f0, 1).mr;
>>> +    if (mr) {
>>>          /* floppy */
>>>          pci_conf[0x82] |= 0x08;
>>> +        memory_region_unref(mr);
>>>      }
>>>  }
>>>  
>>>
>>>
>>
>> Hmm, two solutions for one problem - can we improve this in the next round?
> 
> Sure, I can adapt the hw/acpi/piix4.c to use ifs in the same style as
> hw/isa/lpc_ich9.c (I find the code easier to read).

I was more referring to memory_region_present vs. open-coding.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux