From 886e67100b904cb1b106ed1dfa8a60696aff519a Mon Sep 17 00:00:00 2001 From: Nirmal Patel Date: Wed, 11 May 2022 02:57:06 -0700 Subject: [PATCH 1/2] PCI: vmd: Assign VMD IRQ domain before enumeration 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 Signed-off-by: Lorenzo Pieralisi --- 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(); From c94f732e8001a860b42aa740b0a178a29907463c Mon Sep 17 00:00:00 2001 From: Nirmal Patel Date: Wed, 11 May 2022 02:57:07 -0700 Subject: [PATCH 2/2] PCI: vmd: Revert 2565e5b69c44 ("PCI: vmd: Do not disable MSI-X remapping if interrupt remapping is enabled by IOMMU.") Revert 2565e5b69c44 ("PCI: vmd: Do not disable MSI-X remapping if interrupt remapping is enabled by IOMMU.") The commit 2565e5b69c44 was added as a workaround to keep MSI-X remapping enabled if IOMMU enables interrupt remapping. VMD would keep running in low performance mode. There is no dependency between MSI-X remapping by VMD and interrupt remapping by IOMMU. Link: https://lore.kernel.org/r/20220511095707.25403-3-nirmal.patel@linux.intel.com Signed-off-by: Nirmal Patel Signed-off-by: Lorenzo Pieralisi --- drivers/pci/controller/vmd.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index 5015adc04d19..94a14a3d7e55 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -6,7 +6,6 @@ #include #include -#include #include #include #include @@ -813,8 +812,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) * acceptable because the guest is usually CPU-limited and MSI * remapping doesn't become a performance bottleneck. */ - if (iommu_capable(vmd->dev->dev.bus, IOMMU_CAP_INTR_REMAP) || - !(features & VMD_FEAT_CAN_BYPASS_MSI_REMAP) || + if (!(features & VMD_FEAT_CAN_BYPASS_MSI_REMAP) || offset[0] || offset[1]) { ret = vmd_alloc_irqs(vmd); if (ret)