Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug.

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

>> Yes. Reason I ask is because q35 is adding bridges by default now.
>> Would it be possible to only add them if requested on command line by user
>> instead? I realize some guests expect devices at specific slots
>> but this does not apply to bridges I think?
> 
> I just tried out getting rid of the bridges by default.

That clearly raises the question which devices should be created
automatically by -M q35.  I think the devices which are part of the ich9
chipset should be there by default.  /me looks at my laptop which
happens to have a ich9 chipset.

> So 'lspci' goes from:
> 
> 00:00.0 Host bridge: Intel Corporation 82G33/G31/P35/P31 Express DRAM Controller

Keep.

> 00:01.0 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)

That looks bogous.  Drop.

> 00:02.0 VGA compatible controller: Cirrus Logic GD 5446

Our default vga.

> 00:03.0 Ethernet controller: Intel Corporation 82540EM Gigabit Ethernet Controller (rev 03)

Real ich9 has the e1000 @ 00:19.0, so it would make sense to place one
there.  Adding a default nic will probably create some headache though,
so maybe better don't.

> 00:17.0 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)
> 00:18.0 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)

Looks bogous too, drop.

> 00:1c.0 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)
> 00:1c.1 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)
> 00:1c.2 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)
> 00:1c.3 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)

Real ich9 has these, keep.

> 00:1c.4 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)
> 00:1c.5 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express Root Port 0 (rev 02)

Dunno.  Not present in my laptop, other chipset variants might have more
pcie ports though ...

> 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 92)

Present on real hardware, keep.

> 00:1f.0 ISA bridge: Intel Corporation 82801IB (ICH9) LPC Interface Controller (rev 02)
> 00:1f.2 SATA controller: Intel Corporation 82801IR/IO/IH (ICH9R/DO/DH) 6 port SATA AHCI Controller (rev 02)
> 00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 02)

Keep.

> 03:00.0 PCI bridge: Texas Instruments XIO3130 PCI Express Switch (Upstream) (rev 02)
> 04:00.0 PCI bridge: Texas Instruments XIO3130 PCI Express Switch (Downstream) (rev 01)
> 0c:1c.0 PCI bridge: Digital Equipment Corporation DECchip 21154 (rev 05)
> 0c:1d.0 PCI bridge: Digital Equipment Corporation DECchip 21154 (rev 05)
> 0c:1e.0 PCI bridge: Digital Equipment Corporation DECchip 21154 (rev 05)
> 0c:1f.0 PCI bridge: Digital Equipment Corporation DECchip 21154 (rev 05)

Drop them.  I guess those are just there to simplify bridge device testing.

Real hardware also has:

00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio
Controller (rev 03)

Emulated by intel-hda.

00:1d.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI
Controller #1 (rev 03)
00:1d.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI
Controller #2 (rev 03)
00:1d.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI
Controller #3 (rev 03)
00:1d.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI
Controller #1 (rev 03)

We can emulate those too (see docs/docs/ich9-ehci-uhci.cfg).

I think we should add audio+usb to q35.

cheers,
  Gerd