From 2565e5b69c44b4e42469afea3cc5a97e74d1ed45 Mon Sep 17 00:00:00 2001 From: Adrian Huang Date: Wed, 1 Sep 2021 20:40:47 +0800 Subject: [PATCH] PCI: vmd: Do not disable MSI-X remapping if interrupt remapping is enabled by IOMMU When enabling VMD in BIOS setup (Ice Lake Processor: Whitley platform), the host OS cannot boot successfully with the following error message: nvme nvme0: I/O 12 QID 0 timeout, completion polled nvme nvme0: Shutdown timeout set to 6 seconds DMAR: DRHD: handling fault status reg 2 DMAR: [INTR-REMAP] Request device [0x00:0x00.5] fault index 0xa00 [fault reason 0x25] Blocked a compatibility format interrupt request The request device is the VMD controller: # lspci -s 0000:00.5 -nn 0000:00:00.5 RAID bus controller [0104]: Intel Corporation Volume Management Device NVMe RAID Controller [8086:28c0] (rev 04) `git bisect` points to this offending commit ee81ee84f873 ("PCI: vmd: Disable MSI-X remapping when possible"), which disables VMD MSI remapping. The IOMMU hardware blocks the compatibility format interrupt request because Interrupt Remapping Enable Status (IRES) and Extended Interrupt Mode Enable (EIME) are enabled. Please refer to section "5.1.4 Interrupt-Remapping Hardware Operation" in Intel VT-d spec. To fix the issue, VMD driver still enables the interrupt remapping irrespective of VMD_FEAT_CAN_BYPASS_MSI_REMAP if the IOMMU subsystem enables the interrupt remapping. Test configuration is shown as follows: * Two VMD controllers 1. 8086:28c0 (Whitley's VMD) 2. 8086:201d (Purley's VMD: The issue does not appear in this controller. Just make sure if any side effect occurs.) * w/wo intremap=off Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214219 Link: https://lore.kernel.org/r/20210901124047.1615-1-adrianhuang0701@gmail.com Signed-off-by: Adrian Huang Signed-off-by: Lorenzo Pieralisi Reviewed-by: Jon Derrick Cc: Jon Derrick Cc: Nirmal Patel Cc: Joerg Roedel --- drivers/pci/controller/vmd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index 1b3e94a96414..1979fc5eac27 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -6,6 +6,7 @@ #include #include +#include #include #include #include @@ -765,7 +766,8 @@ 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 (!(features & VMD_FEAT_CAN_BYPASS_MSI_REMAP) || + if (iommu_capable(vmd->dev->dev.bus, IOMMU_CAP_INTR_REMAP) || + !(features & VMD_FEAT_CAN_BYPASS_MSI_REMAP) || offset[0] || offset[1]) { ret = vmd_alloc_irqs(vmd); if (ret)