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Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug.
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug. |
Date: |
Thu, 11 Oct 2012 22:40:04 +0200 |
On Thu, Oct 11, 2012 at 11:34:08AM -0400, Jason Baron wrote:
> On Thu, Oct 11, 2012 at 04:46:56PM +0200, Michael S. Tsirkin wrote:
> > On Thu, Oct 11, 2012 at 10:21:22AM -0400, Jason Baron wrote:
> > > On Thu, Oct 11, 2012 at 12:57:06PM +0200, Michael S. Tsirkin wrote:
> > > > On Mon, Oct 08, 2012 at 11:30:39PM -0400, Jason Baron wrote:
> > > > > From: Jason Baron <address@hidden>
> > > > >
> > > > > Add piix style acpi hotplug to q35.
> > > > >
> > > > > Signed-off-by: Jason Baron <address@hidden>
> > > >
> > > > Something I don't understand here: this only handles hotplug
> > > > of devices behind the root, no?
> > > > Don't we need support for hotplug/hot remove of devices behind
> > > > bridges?
> > > >
> > >
> > > Yes, this only handles acpi hotplug of devices behind the root. I'm
> > > trying to reach minimal set of q35 patches that we can build upon. I
> > > think that this patch gives us at least the same functionality as piix
> > > does. (Plus there is pcie hotplug).
> > >
> > > As you know, I have a proof of concept patch series providing a second
> > > level of hotplug behind bridges. Unfortunately, it was based on the
> > > static acpi tables, before Paolo made the hotplug table generation
> > > dynamic. So it needs quite a bit of re-work. But I know that it should
> > > work :)
> > >
> > > Thanks,
> > >
> > > -Jason
> >
> > 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.
>
> So 'lspci' goes from:
>
> 00:00.0 Host bridge: Intel Corporation 82G33/G31/P35/P31 Express DRAM
> Controller
> 00:01.0 PCI bridge: Intel Corporation 5500 Non-Legacy I/O Hub PCI Express
> Root Port 0 (rev 02)
> 00:02.0 VGA compatible controller: Cirrus Logic GD 5446
> 00:03.0 Ethernet controller: Intel Corporation 82540EM Gigabit Ethernet
> Controller (rev 03)
> 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)
> 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)
> 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)
> 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 92)
> 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)
> 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)
>
> To:
>
> 00:00.0 Host bridge: Intel Corporation 82G33/G31/P35/P31 Express DRAM
> Controller
> 00:01.0 VGA compatible controller: Cirrus Logic GD 5446
> 00:02.0 Ethernet controller: Intel Corporation 82540EM Gigabit Ethernet
> Controller (rev 03)
> 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 92)
> 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)
>
>
> Windows and Linux guests seem fine with either layout. Slots 1-2 are
> specific to my setup. So this is a pretty minimal set.
I guess we can remove the PCI bridge too?
One interesting side effect here is that there are less free pci slots
on root bus now. I guess at minimum management needs to be taught about
this, and I'm not sure how.
> I think that providing the minimal set of devices is good, since it
> allows the user to configure things as much as possible. So I am in
> favor of this more minimal set. My only hesitation is that we pull out,
> or that I have not included some important piece h/w at a specific slot
> that a guest might need. Thus potentially breaking existing setups.
> Perhaps, that might mean a new machine type in the future, if we've
> messed up?
Yes, that's one solution.
> These devices and slots are pulled from the Intel docs on ICH9 and Q35
> specs. See:
>
> http://www.intel.com/content/www/us/en/io/io-controller-hub-9-datasheet.html
>
> Perhaps, Yamahata can comment further on the specific set of bridges?
>
> > It would also be nice to add comments explaining why
> > specific slots were selected e.g. /* BSD XYZ fails to boot unless ahci is
> > at alow 2 */
> > etc.
>
> Right, its basically just pulled from the Intel spec as mentioned above.
>
> >
> > Also - will adding this code now mean that when adding bridges
> > we'll need to add compatibility code in bios/qemu in the future?
> >
>
> I don't think so, but maybe you can elaborate this concern more
> specifically?
>
> Thanks,
>
> -Jason
Just this: can same bios work on this interface and the one
you intend for hotplug behind bridge? Or will we need to version
interface?
--
MST
- Re: [Qemu-devel] [PATCH v2 20/21] q35: automatically load the q35 dsdt table, (continued)
- [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Jason Baron, 2012/10/08
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Paolo Bonzini, 2012/10/09
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Michael S. Tsirkin, 2012/10/11
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Jason Baron, 2012/10/11
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug.,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Jason Baron, 2012/10/12
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Michael S. Tsirkin, 2012/10/13
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Gerd Hoffmann, 2012/10/12
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Michael S. Tsirkin, 2012/10/12
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Gerd Hoffmann, 2012/10/12
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Michael S. Tsirkin, 2012/10/12
- Re: [Qemu-devel] [PATCH v2 21/21] q35: add acpi-based pci hotplug., Jason Baron, 2012/10/12
[Qemu-devel] [PATCH v2 13/21] q35: Re-base q35, Jason Baron, 2012/10/08