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 8497028..2a90121 100644
--- 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 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 @@
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 @@
}
}
+ 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;