[Feature] Volume Management Device (VMD) Driver

[XiongZhang]

The Volume Management Device (VMD) is a secondary PCI Express host bridge provided by the Intel CPU. Individual CPU-attached root ports, and all devices behind them, may be configured by BIOS to appear underneath VMD instead of underneath the primary root bus.
VMD is represented by a root bus integrated endpoint, which serves as a proxy to the devices beneath it for access to configuration space, MMIO, DMA, and MSI.
The VMD driver implements Linux's PCI host bridge interface. When probed, the driver dynamically creates a new PCI domain(segment). The PCI subsystem enumerates the VMD PCI domain and loads drivers for devices and ports it finds.
A software validation team is testing the driver with VMD-enabled servers, PCIe switches, and NVMe PCIe SSDs. They will also be testing error handling and hotplug for SSDs behind VMD-owned root ports.
http://www.intel.com/cd/edesign/library/asmo-na/eng/546831.htm (CNDA)
http://www.intel.com/cd/edesign/library/asmo-na/eng/546833.htm (CNDA).

HW: Purley

Upstream statues:
v4.5 kernel implement this with:
185a383 x86/PCI: Add driver for Intel Volume Management Device (VMD)
28ef241 PCI/AER: Use 32 bit PCI domain numbers
d9c3d6f x86/PCI: Allow DMA ops specific to a PCI domain
64bce3e irqdomain: Export irq_domain_set_info() for module use
bf6f869 genirq/MSI: Relax msi_domain_alloc() to support parentless MSI irqdomain

[Leann Ogasawara (leannogasawara)]

The v4.8 based kernel has been uploaded to the Yakkety 16.10 archive. I'm setting this to Fix Released.

[Leann Ogasawara (leannogasawara)]

git describe --contains 185a383
v4.5-rc1~33^2~2^2

commit 185a383ada2e7794b0e82e040223e741b24d2bf8
Author: Keith Busch <email address hidden>
Date: Tue Jan 12 13:18:10 2016 -0700

    x86/PCI: Add driver for Intel Volume Management Device (VMD)

git describe --contains 28ef241
v4.5-rc1~33^2~2^2~1

commit 28ef241f05c20c2f04b349d43c615438f7e6f811
Author: Keith Busch <email address hidden>
Date: Tue Jan 12 13:18:09 2016 -0700

    PCI/AER: Use 32 bit PCI domain numbers

git describe --contains d9c3d6f
v4.5-rc1~33^2~2^2~2

commit d9c3d6ff227cbdf05399ba8303bdcd0d35bbfccb
Author: Keith Busch <email address hidden>
Date: Tue Jan 12 13:18:08 2016 -0700

    x86/PCI: Allow DMA ops specific to a PCI domain

git describe --contains 64bce3e
v4.5-rc1~33^2~2^2~3

commit 64bce3e8bfb3cf2cbc638296390af3e02e747347
Author: Keith Busch <email address hidden>
Date: Tue Jan 12 13:18:07 2016 -0700

    irqdomain: Export irq_domain_set_info() for module use

git describe --contains bf6f869
v4.5-rc1~33^2~2^2~4

commit bf6f869f8c111ba265cd199c64b25c646987500a
Author: Liu Jiang <email address hidden>
Date: Tue Jan 12 13:18:06 2016 -0700

    genirq/MSI: Relax msi_domain_alloc() to support parentless MSI irqdomains