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Re: [Qemu-devel] [PATCH v4 for-2.3 13/25] hw/acpi: remove from root bus
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v4 for-2.3 13/25] hw/acpi: remove from root bus 0 the crs resources used by other busses. |
Date: |
Tue, 10 Mar 2015 13:09:36 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Mon, Mar 09, 2015 at 09:44:24AM +0100, Michael S. Tsirkin wrote:
> On Sun, Mar 08, 2015 at 02:46:28PM -0400, Kevin O'Connor wrote:
> > On Sun, Mar 08, 2015 at 07:34:34PM +0100, Michael S. Tsirkin wrote:
> > > On Sun, Mar 08, 2015 at 12:13:40PM -0400, Kevin O'Connor wrote:
> > > > If I read this correctly, it looks like a machine with two root buses
> > > > and 20 devices, each with one memory range and one io range, would end
> > > > up with 40 CRS ranges (ie, a CRS range for every resource).
> > >
> > > I think that's only if you stick multiple devices directly behind the
> > > bridge. Looks like with a single pci bridge behind root, there will
> > > only be 2 ranges.
> >
> > Yeah, that makes sense, so doesn't seem to be a problem.
> >
> > > Maybe try to enforce this sane topology?
> > >
> > > > It also
> > > > looks like this furthers the requirement that the guest firmware
> > > > assign the PCI resources prior to QEMU being able to generate the ACPI
> > > > tables.
> > >
> > > That seems unavoidable unless we want to assign ranges from
> > > hardware/management.
> > > Which I think would be a mistake: management doesn't really know,
> > > or care.
> >
> > I understand. I think what would help me is if we could document
> > somewhere that the firmware has to assign PCI resources before
> > querying the bios tables and that it is the *only* pre-requisite for
> > querying them. Looking now, though, I don't see any fw_cfg
> > documentation in the repo, so I'm not sure where that could be added.
> >
> > Thanks,
> > -Kevin
>
> Sigh. Might make a GSoC project?
Documentation projects are not possible under Google Summer of Code:
https://www.google-melange.com/gsoc/document/show/gsoc_program/google/gsoc2015/help_page#12._Are_proposals_for_documentation_work
If there is a coding project you are interested in mentoring, there is a
project idea template to fill out here:
http://qemu-project.org/Google_Summer_of_Code_2015#Project_idea_template
Stefan
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- Re: [Qemu-devel] [PATCH v4 for-2.3 12/25] hw/acpi: add _CRS method for extra root busses, (continued)
[Qemu-devel] [PATCH v4 for-2.3 15/25] hw/pci: made pci_bus_is_root a PCIBusClass method, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 16/25] hw/pci: made pci_bus_num a PCIBusClass method, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 14/25] hw/pci: move pci bus related code to separate files, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 18/25] hw/pci: removed 'rootbus nr is 0' assumption from qmp_pci_query, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 17/25] hw/pci: introduce TYPE_PCI_MAIN_HOST_BRIDGE interface, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 19/25] hw/pci: implement iteration over multiple host bridges, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 20/25] hw/pci: introduce PCI Expander Bridge (PXB), Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 22/25] hw/pci: piix - suport multiple host bridges, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 24/25] hw/pci_bus: add support for NUMA nodes, Marcel Apfelbaum, 2015/03/08
[Qemu-devel] [PATCH v4 for-2.3 21/25] hw/pci: inform bios if the system has more than one pci bridge, Marcel Apfelbaum, 2015/03/08