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Date: Fri, 1 Dec 2023 16:45:56 -0600
From: Bjorn Helgaas <helgaas@kernel.org>
To: Rob Herring <robh@kernel.org>
Cc: Herve Codina <herve.codina@bootlin.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>, Lizhi Hou <lizhi.hou@amd.com>,
	Max Zhen <max.zhen@amd.com>, Sonal Santan <sonal.santan@amd.com>,
	Stefano Stabellini <stefano.stabellini@xilinx.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	PCI <linux-pci@vger.kernel.org>,
	Allan Nielsen <allan.nielsen@microchip.com>,
	Horatiu Vultur <horatiu.vultur@microchip.com>,
	Steen Hegelund <steen.hegelund@microchip.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v2 0/2] Attach DT nodes to existing PCI devices
Message-ID: <20231201224556.GA534342@bhelgaas>
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On Fri, Dec 01, 2023 at 04:26:45PM -0600, Rob Herring wrote:
> On Thu, Nov 30, 2023 at 10:57 AM Herve Codina <herve.codina@bootlin.com> wrote:
> ...

> Also, no idea if the bridge part works because my qemu setup doesn't
> create bridges (anyone got a magic cmdline to create them?).

I probably copied this from somewhere and certainly couldn't construct
it from scratch, but it did create a hierarchy like this:

  00:04.0 bridge to [bus 01-04] (Root Port)
  01:00.0 bridge to [bus 02-04] (Switch Upstream Port)
  02:00.0 bridge to [bus 03] (Switch Downstream Port)
  02:01.0 bridge to [bus 04] (Switch Downstream Port)
  03:00.0 endpoint
  04:00.0 endpoint

  IMAGE=ubuntu.img
  KERNEL=~/linux/arch/x86/boot/bzImage
  IMGDIR=~/virt/img/

  qemu-system-x86_64 -enable-kvm -s -m 2048 $IMAGE \
      -device pcie-root-port,id=root_port1,chassis=1,slot=1 \
      -device x3130-upstream,id=upstream_port1,bus=root_port1 \
      -device xio3130-downstream,id=downstream_port1,bus=upstream_port1,chassis=2,slot=1 \
      -device xio3130-downstream,id=downstream_port2,bus=upstream_port1,chassis=2,slot=2 \
      -drive file=${IMGDIR}/nvme.qcow2,if=none,id=nvme1,snapshot=on \
      -device nvme,drive=nvme1,serial=nvme1,cmb_size_mb=2048,bus=downstream_port1 \
      -drive file=${IMGDIR}/nvme2.qcow2,if=none,id=nvme2,snapshot=on \
      -device nvme,drive=nvme2,serial=nvme1,bus=downstream_port2 \
      -virtfs local,id=home,path=/home/,security_model=mapped,mount_tag=home \
      -nographic \
      -kernel $KERNEL \
      -append "root=/dev/sda2 rootfstype=ext4 console=ttyS0,38400n8"