PCI: vmd: Assign VMD IRQ domain before enumeration

PCI: vmd: Assign VMD IRQ domain before enumeration

commit 886e67100b904cb1b106ed1dfa8a60696aff519a upstream.

During the boot process all the PCI devices are assigned default PCI-MSI
IRQ domain including VMD endpoint devices. If interrupt-remapping is
enabled by IOMMU, the PCI devices except VMD get new INTEL-IR-MSI IRQ
domain. And VMD is supposed to create and assign a separate VMD-MSI IRQ
domain for its child devices in order to support MSI-X remapping
capabilities.

Now when MSI-X remapping in VMD is disabled in order to improve
performance, VMD skips VMD-MSI IRQ domain assignment process to its
child devices. Thus the devices behind VMD get default PCI-MSI IRQ
domain instead of INTEL-IR-MSI IRQ domain when VMD creates root bus and
configures child devices.

As a result host OS fails to boot and DMAR errors were observed when
interrupt remapping was enabled on Intel Icelake CPUs. For instance:

  DMAR: DRHD: handling fault status reg 2
  DMAR: [INTR-REMAP] Request device [0xe2:0x00.0] fault index 0xa00 [fault reason 0x25] Blocked a compatibility format interrupt request

To fix this issue, dev_msi_info struct in dev struct maintains correct
value of IRQ domain. VMD will use this information to assign proper IRQ
domain to its child devices when it doesn't create a separate IRQ domain.

Link: https://lore.kernel.org/r/20220511095707.25403-2-nirmal.patel@linux.intel.com
Signed-off-by: Nirmal Patel <nirmal.patel@linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[ This patch has already been backported to the Ubuntu 5.15 kernel
  and fixes boot issues on Intel platforms with VMD rev 04,
  confirmed on version 5.15.189. ]
Signed-off-by: Artur Piechocki <artur.piechocki@open-e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>