1 files changed, 25 insertions, 14 deletions

diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index 9eff36a293e0..3a0cb0bb0593 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -15,6 +15,14 @@ static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
 static int ir_ioapic_num;
 int intr_remapping_enabled;
 
+static int disable_intremap;
+static __init int setup_nointremap(char *str)
+{
+        disable_intremap = 1;
+        return 0;
+}
+early_param("nointremap", setup_nointremap);
+
 struct irq_2_iommu {
         struct intel_iommu *iommu;
         u16 irte_index;
@@ -420,20 +428,6 @@ static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
                       readl, (sts & DMA_GSTS_IRTPS), sts);
         spin_unlock_irqrestore(&iommu->register_lock, flags);
 
-        if (mode == 0) {
-                spin_lock_irqsave(&iommu->register_lock, flags);
-
-                /* enable comaptiblity format interrupt pass through */
-                cmd = iommu->gcmd | DMA_GCMD_CFI;
-                iommu->gcmd |= DMA_GCMD_CFI;
-                writel(cmd, iommu->reg + DMAR_GCMD_REG);
-
-                IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
-                              readl, (sts & DMA_GSTS_CFIS), sts);
-
-                spin_unlock_irqrestore(&iommu->register_lock, flags);
-        }
-
         /*
          * global invalidation of interrupt entry cache before enabling
          * interrupt-remapping.
@@ -513,6 +507,23 @@ end:
         spin_unlock_irqrestore(&iommu->register_lock, flags);
 }
 
+int __init intr_remapping_supported(void)
+{
+        struct dmar_drhd_unit *drhd;
+
+        if (disable_intremap)
+                return 0;
+
+        for_each_drhd_unit(drhd) {
+                struct intel_iommu *iommu = drhd->iommu;
+
+                if (!ecap_ir_support(iommu->ecap))
+                        return 0;
+        }
+
+        return 1;
+}
+
 int __init enable_intr_remapping(int eim)
 {
         struct dmar_drhd_unit *drhd;