From: Nirmal Patel <nirmal.patel(a)linux.intel.com>
[ Upstream commit 886e67100b904cb1b106ed1dfa8a60696aff519a ]
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.c…
Signed-off-by: Nirmal Patel <nirmal.patel(a)linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi(a)arm.com>
(cherry picked from commit 886e67100b904cb1b106ed1dfa8a60696aff519a)
[ 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(a)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 846590706a38..d0d18e9c6968 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -799,6 +799,9 @@ 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));
WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj,
"domain"), "Can't create symlink to domain\n");
--
2.50.1