From 074835f0143b83845af5044af2739c52c9f53808 Mon Sep 17 00:00:00 2001 From: Youquan Song Date: Wed, 9 Sep 2009 12:05:39 -0400 Subject: [PATCH] intel-iommu: Fix kernel hang if interrupt remapping disabled in BIOS BIOS clear DMAR table INTR_REMAP flag to disable interrupt remapping. Current kernel only check interrupt remapping(IR) flag in DRHD's extended capability register to decide interrupt remapping support or not. But IR flag will not change when BIOS disable/enable interrupt remapping. When user disable interrupt remapping in BIOS or BIOS often defaultly disable interrupt remapping feature when BIOS is not mature.Though BIOS disable interrupt remapping but intr_remapping_supported function will always report to OS support interrupt remapping if VT-d2 chipset populated. On this cases, kernel will continue enable interrupt remapping and result kernel panic. This bug exist on almost all platforms with interrupt remapping support. This patch add DMAR table INTR_REMAP flag check before enable interrupt remapping. Signed-off-by: Youquan Song Signed-off-by: David Woodhouse --- drivers/pci/dmar.c | 10 ++++++++++ drivers/pci/intr_remapping.c | 3 +++ include/linux/intel-iommu.h | 2 ++ 3 files changed, 15 insertions(+) diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c index fba4f6891680..270ed222a075 100644 --- a/drivers/pci/dmar.c +++ b/drivers/pci/dmar.c @@ -1316,3 +1316,13 @@ int dmar_reenable_qi(struct intel_iommu *iommu) return 0; } + +/* + * Check interrupt remapping support in DMAR table description. + */ +int dmar_ir_support(void) +{ + struct acpi_table_dmar *dmar; + dmar = (struct acpi_table_dmar *)dmar_tbl; + return dmar->flags & 0x1; +} diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c index ebfa47b79c5b..ac065144c01c 100644 --- a/drivers/pci/intr_remapping.c +++ b/drivers/pci/intr_remapping.c @@ -611,6 +611,9 @@ int __init intr_remapping_supported(void) if (disable_intremap) return 0; + if (!dmar_ir_support()) + return 0; + for_each_drhd_unit(drhd) { struct intel_iommu *iommu = drhd->iommu; diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index 482dc91fd53a..4f0a72a9740c 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -360,4 +360,6 @@ extern void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 qdep, extern int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu); +extern int dmar_ir_support(void); + #endif -- 2.39.2