From: Nirmal Patel nirmal.patel@linux.intel.com
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.co... Cc: stable@vger.kernel.org Signed-off-by: Nirmal Patel nirmal.patel@linux.intel.com Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Signed-off-by: Artur Piechocki artur.piechocki@open-e.com --- drivers/pci/controller/vmd.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index eb05cceab964..5015adc04d19 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -853,6 +853,9 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) vmd_attach_resources(vmd); if (vmd->irq_domain) dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain); + else + dev_set_msi_domain(&vmd->bus->dev, + dev_get_msi_domain(&vmd->dev->dev));
vmd_acpi_begin();