Re: [Qemu-devel] [PATCH V3 3/3] hw/i386: extend pxb query for all PC machines

[Eduardo Habkost]

On Tue, Dec 01, 2015 at 10:53:07PM +0200, Marcel Apfelbaum wrote:
> On 12/01/2015 08:20 PM, Eduardo Habkost wrote:
> >On Thu, Nov 26, 2015 at 06:00:28PM +0200, Marcel Apfelbaum wrote:
> >>Add bus property to PC machines and use it when looking
> >>for primary PCI root bus (bus 0).
> >>
> >>Signed-off-by: Marcel Apfelbaum <address@hidden>
> >>---
> >>  hw/i386/acpi-build.c | 3 +--
> >>  hw/i386/pc.c         | 2 +-
> >>  hw/i386/pc_piix.c    | 1 +
> >>  hw/i386/pc_q35.c     | 1 +
> >>  include/hw/i386/pc.h | 1 +
> >>  5 files changed, 5 insertions(+), 3 deletions(-)
> >>
> >>diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >>index 736b252..bca3f06 100644
> >>--- a/hw/i386/acpi-build.c
> >>+++ b/hw/i386/acpi-build.c
> >>@@ -950,8 +950,7 @@ build_ssdt(GArray *table_data, GArray *linker,
> >>      /* Reserve space for header */
> >>      acpi_data_push(ssdt->buf, sizeof(AcpiTableHeader));
> >>
> >>-    /* Extra PCI root buses are implemented  only for i440fx */
> >>-    bus = find_i440fx();
> >>+    bus = PC_MACHINE(machine)->bus;
> >
> >You can use acpi_get_i386_pci_host()->bus here, so we can reduce
> >the amount of PC-specific code inside acpi-build.c.
> >
> >(Making acpi_get_i386_pci_host() more generic and not depend on
> >piix- and q35-specific checks is also on my plans)
> 
> Well, at this point, looking at the names PC_MACHINE and 
> acpi_get_i386_pci_host,
> I don't see much difference :)

I'm a bit confused by how generic acpi-build.c is supposed to be.
It has some code that seems to be an attempt to be more generic
(e.g. the "if (pci_host)" check at build_ssdt()), but lots of
other code that only work with PC machines. Maybe we should stop
pretending and simply use PCMachineState everywhere inside
acpi-build.c?

> I think we can change this later when acpi_get_i386_pci_host will be generic.

No problem to me. :)

-- 
Eduardo