iommu/vt-d: Copy IR table from old kernel when in kdump mode

When we are booting into a kdump kernel and find IR enabled,
copy over the contents of the previous IR table so that
spurious interrupts will not be target aborted.

Tested-by: ZhenHua Li <zhen-hual@hp.com>
Tested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 84970281b754a4fc4d55ba6856969b07fc403c74..2a901219f953065746b92dab03abb1e5b56ed5e6 100644 (file)
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -11,6 +11,7 @@
 #include <linux/irq.h>
 #include <linux/intel-iommu.h>
 #include <linux/acpi.h>
+#include <linux/crash_dump.h>
 #include <asm/io_apic.h>
 #include <asm/smp.h>
 #include <asm/cpu.h>
@@ -54,8 +55,28 @@ static struct hpet_scope ir_hpet[MAX_HPET_TBS];
  */
 static DEFINE_RAW_SPINLOCK(irq_2_ir_lock);
 
+static void iommu_disable_irq_remapping(struct intel_iommu *iommu);
 static int __init parse_ioapics_under_ir(void);
 
+static bool ir_pre_enabled(struct intel_iommu *iommu)
+{
+       return (iommu->flags & VTD_FLAG_IRQ_REMAP_PRE_ENABLED);
+}
+
+static void clear_ir_pre_enabled(struct intel_iommu *iommu)
+{
+       iommu->flags &= ~VTD_FLAG_IRQ_REMAP_PRE_ENABLED;
+}
+
+static void init_ir_status(struct intel_iommu *iommu)
+{
+       u32 gsts;
+
+       gsts = readl(iommu->reg + DMAR_GSTS_REG);
+       if (gsts & DMA_GSTS_IRES)
+               iommu->flags |= VTD_FLAG_IRQ_REMAP_PRE_ENABLED;
+}
+
 static struct irq_2_iommu *irq_2_iommu(unsigned int irq)
 {
        struct irq_cfg *cfg = irq_cfg(irq);
@@ -426,6 +447,44 @@ static int set_msi_sid(struct irte *irte, struct pci_dev *dev)
        return 0;
 }
 
+static int iommu_load_old_irte(struct intel_iommu *iommu)
+{
+       struct irte *old_ir_table;
+       phys_addr_t irt_phys;
+       size_t size;
+       u64 irta;
+
+       if (!is_kdump_kernel()) {
+               pr_warn("IRQ remapping was enabled on %s but we are not in kdump mode\n",
+                       iommu->name);
+               clear_ir_pre_enabled(iommu);
+               iommu_disable_irq_remapping(iommu);
+               return -EINVAL;
+       }
+
+       /* Check whether the old ir-table has the same size as ours */
+       irta = dmar_readq(iommu->reg + DMAR_IRTA_REG);
+       if ((irta & INTR_REMAP_TABLE_REG_SIZE_MASK)
+            != INTR_REMAP_TABLE_REG_SIZE)
+               return -EINVAL;
+
+       irt_phys = irta & VTD_PAGE_MASK;
+       size     = INTR_REMAP_TABLE_ENTRIES*sizeof(struct irte);
+
+       /* Map the old IR table */
+       old_ir_table = ioremap_cache(irt_phys, size);
+       if (!old_ir_table)
+               return -ENOMEM;
+
+       /* Copy data over */
+       memcpy(iommu->ir_table->base, old_ir_table, size);
+
+       __iommu_flush_cache(iommu, iommu->ir_table->base, size);
+
+       return 0;
+}
+
+
 static void iommu_set_irq_remapping(struct intel_iommu *iommu, int mode)
 {
        unsigned long flags;
@@ -531,6 +590,17 @@ static int intel_setup_irq_remapping(struct intel_iommu *iommu)
                }
        }
 
+       init_ir_status(iommu);
+
+       if (ir_pre_enabled(iommu)) {
+               if (iommu_load_old_irte(iommu))
+                       pr_err("Failed to copy IR table for %s from previous kernel\n",
+                              iommu->name);
+               else
+                       pr_info("Copied IR table for %s from previous kernel\n",
+                               iommu->name);
+       }
+
        iommu_set_irq_remapping(iommu, eim_mode);
 
        return 0;

diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index b85b81ad5ebae59c4d57c1390e3dc314c7e0a8af..9e14edcf7f6e31245f0ef13950e1166e0f9e51d2 100644 (file)
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -296,6 +296,7 @@ struct q_inval {
 /* 1MB - maximum possible interrupt remapping table size */
 #define INTR_REMAP_PAGE_ORDER  8
 #define INTR_REMAP_TABLE_REG_SIZE      0xf
+#define INTR_REMAP_TABLE_REG_SIZE_MASK  0xf
 
 #define INTR_REMAP_TABLE_ENTRIES       65536