Re: [Qemu-devel] [PATCH 06/16] acpi: Save PCMachineState on AcpiBuildState

[Marcel Apfelbaum <marcel.apfelbaum@gmail.com>]

On 12/08/2015 07:59 PM, Eduardo Habkost wrote:
> On Mon, Dec 07, 2015 at 05:39:29PM +0200, Marcel Apfelbaum wrote:
>> On 12/02/2015 03:47 AM, Eduardo Habkost wrote:
>>> PCMachineState will be used in some of the steps of ACPI table
>>> building.
>>>
>>> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
>>> ---
>>>   hw/i386/acpi-build.c | 8 ++++----
>>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
>>> index 85a5c53..ca11c88 100644
>>> --- a/hw/i386/acpi-build.c
>>> +++ b/hw/i386/acpi-build.c
>>> @@ -1644,7 +1644,7 @@ struct AcpiBuildState {
>>>       MemoryRegion *table_mr;
>>>       /* Is table patched? */
>>>       uint8_t patched;
>>> -    PcGuestInfo *guest_info;
>>> +    PCMachineState *pcms;
>>>       void *rsdp;
>>>       MemoryRegion *rsdp_mr;
>>>       MemoryRegion *linker_mr;
>>> @@ -1855,7 +1855,7 @@ static void acpi_build_update(void *build_opaque, uint32_t offset)
>>>
>>>       acpi_build_tables_init(&tables);
>>>
>>> -    acpi_build(build_state->guest_info, &tables);
>>> +    acpi_build(&build_state->pcms->acpi_guest_info, &tables);
>>>
>>>       acpi_ram_update(build_state->table_mr, tables.table_data);
>>>
>>> @@ -1916,12 +1916,12 @@ void acpi_setup(PCMachineState *pcms)
>>>
>>>       build_state = g_malloc0(sizeof *build_state);
>>>
>>> -    build_state->guest_info = guest_info;
>>> +    build_state->pcms = pcms;
>>
>> I am not "sold" on keeping a reference to machine in the build_state.
>> We can always query current machine using qdev_machine() or something.
>>
>> Keeping the "guest info" made sense since is used especially for ACPI,
>> however the machine has a wider scope. (And not having to keep it
>> around is a very good thing!)
>
> I wouldn't mind using qdev_get_machine() if preferred by the
> maintainer of that code, but I like to avoid it when possible. To
> me, qdev_get_machine() is just a global variable disguised as a
> harder-to-understand API.

Really? Hmm, for me is looking like the other way around :)
I see it as "query the QOM tree", instead of "keep the reference around" everywhere.
But it may be just a personal preference.

Thanks,
Marcel



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