3 files changed, 70 insertions, 27 deletions

diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index f5a662a50acb..26c536b51c5a 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -330,6 +330,14 @@ parse_dmar_table(void)
         entry_header = (struct acpi_dmar_header *)(dmar + 1);
         while (((unsigned long)entry_header) <
                         (((unsigned long)dmar) + dmar_tbl->length)) {
+                /* Avoid looping forever on bad ACPI tables */
+                if (entry_header->length == 0) {
+                        printk(KERN_WARNING PREFIX
+                                "Invalid 0-length structure\n");
+                        ret = -EINVAL;
+                        break;
+                }
+
                 dmar_table_print_dmar_entry(entry_header);
 
                 switch (entry_header->type) {
@@ -491,7 +499,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
         int map_size;
         u32 ver;
         static int iommu_allocated = 0;
-        int agaw;
+        int agaw = 0;
 
         iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
         if (!iommu)
@@ -507,6 +515,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
         iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
         iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
 
+#ifdef CONFIG_DMAR
         agaw = iommu_calculate_agaw(iommu);
         if (agaw < 0) {
                 printk(KERN_ERR
@@ -514,6 +523,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
                         iommu->seq_id);
                 goto error;
         }
+#endif
         iommu->agaw = agaw;
 
         /* the registers might be more than one page */
@@ -571,19 +581,49 @@ static inline void reclaim_free_desc(struct q_inval *qi)
         }
 }
 
+static int qi_check_fault(struct intel_iommu *iommu, int index)
+{
+        u32 fault;
+        int head;
+        struct q_inval *qi = iommu->qi;
+        int wait_index = (index + 1) % QI_LENGTH;
+
+        fault = readl(iommu->reg + DMAR_FSTS_REG);
+
+        /*
+         * If IQE happens, the head points to the descriptor associated
+         * with the error. No new descriptors are fetched until the IQE
+         * is cleared.
+         */
+        if (fault & DMA_FSTS_IQE) {
+                head = readl(iommu->reg + DMAR_IQH_REG);
+                if ((head >> 4) == index) {
+                        memcpy(&qi->desc[index], &qi->desc[wait_index],
+                                        sizeof(struct qi_desc));
+                        __iommu_flush_cache(iommu, &qi->desc[index],
+                                        sizeof(struct qi_desc));
+                        writel(DMA_FSTS_IQE, iommu->reg + DMAR_FSTS_REG);
+                        return -EINVAL;
+                }
+        }
+
+        return 0;
+}
+
 /*
  * Submit the queued invalidation descriptor to the remapping
  * hardware unit and wait for its completion.
  */
-void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
+int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
 {
+        int rc = 0;
         struct q_inval *qi = iommu->qi;
         struct qi_desc *hw, wait_desc;
         int wait_index, index;
         unsigned long flags;
 
         if (!qi)
-                return;
+                return 0;
 
         hw = qi->desc;
 
@@ -601,7 +641,8 @@ void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
 
         hw[index] = *desc;
 
-        wait_desc.low = QI_IWD_STATUS_DATA(2) | QI_IWD_STATUS_WRITE | QI_IWD_TYPE;
+        wait_desc.low = QI_IWD_STATUS_DATA(QI_DONE) |
+                        QI_IWD_STATUS_WRITE | QI_IWD_TYPE;
         wait_desc.high = virt_to_phys(&qi->desc_status[wait_index]);
 
         hw[wait_index] = wait_desc;
@@ -612,13 +653,11 @@ void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
         qi->free_head = (qi->free_head + 2) % QI_LENGTH;
         qi->free_cnt -= 2;
 
-        spin_lock(&iommu->register_lock);
         /*
          * update the HW tail register indicating the presence of
          * new descriptors.
          */
         writel(qi->free_head << 4, iommu->reg + DMAR_IQT_REG);
-        spin_unlock(&iommu->register_lock);
 
         while (qi->desc_status[wait_index] != QI_DONE) {
                 /*
@@ -628,15 +667,21 @@ void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
                  * a deadlock where the interrupt context can wait indefinitely
                  * for free slots in the queue.
                  */
+                rc = qi_check_fault(iommu, index);
+                if (rc)
+                        goto out;
+
                 spin_unlock(&qi->q_lock);
                 cpu_relax();
                 spin_lock(&qi->q_lock);
         }
-
-        qi->desc_status[index] = QI_DONE;
+out:
+        qi->desc_status[index] = qi->desc_status[wait_index] = QI_DONE;
 
         reclaim_free_desc(qi);
         spin_unlock_irqrestore(&qi->q_lock, flags);
+
+        return rc;
 }
 
 /*
@@ -649,13 +694,13 @@ void qi_global_iec(struct intel_iommu *iommu)
         desc.low = QI_IEC_TYPE;
         desc.high = 0;
 
+        /* should never fail */
         qi_submit_sync(&desc, iommu);
 }
 
 int qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid, u8 fm,
                      u64 type, int non_present_entry_flush)
 {
-
         struct qi_desc desc;
 
         if (non_present_entry_flush) {
@@ -669,10 +714,7 @@ int qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid, u8 fm,
                         | QI_CC_GRAN(type) | QI_CC_TYPE;
         desc.high = 0;
 
-        qi_submit_sync(&desc, iommu);
-
-        return 0;
-
+        return qi_submit_sync(&desc, iommu);
 }
 
 int qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
@@ -702,10 +744,7 @@ int qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
         desc.high = QI_IOTLB_ADDR(addr) | QI_IOTLB_IH(ih)
                 | QI_IOTLB_AM(size_order);
 
-        qi_submit_sync(&desc, iommu);
-
-        return 0;
-
+        return qi_submit_sync(&desc, iommu);
 }
 
 /*
diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index f78371b22529..45effc5726c0 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -207,7 +207,7 @@ int alloc_irte(struct intel_iommu *iommu, int irq, u16 count)
         return index;
 }
 
-static void qi_flush_iec(struct intel_iommu *iommu, int index, int mask)
+static int qi_flush_iec(struct intel_iommu *iommu, int index, int mask)
 {
         struct qi_desc desc;
 
@@ -215,7 +215,7 @@ static void qi_flush_iec(struct intel_iommu *iommu, int index, int mask)
                    | QI_IEC_SELECTIVE;
         desc.high = 0;
 
-        qi_submit_sync(&desc, iommu);
+        return qi_submit_sync(&desc, iommu);
 }
 
 int map_irq_to_irte_handle(int irq, u16 *sub_handle)
@@ -283,6 +283,7 @@ int clear_irte_irq(int irq, struct intel_iommu *iommu, u16 index)
 
 int modify_irte(int irq, struct irte *irte_modified)
 {
+        int rc;
         int index;
         struct irte *irte;
         struct intel_iommu *iommu;
@@ -303,14 +304,15 @@ int modify_irte(int irq, struct irte *irte_modified)
         set_64bit((unsigned long *)irte, irte_modified->low | (1 << 1));
         __iommu_flush_cache(iommu, irte, sizeof(*irte));
 
-        qi_flush_iec(iommu, index, 0);
-
+        rc = qi_flush_iec(iommu, index, 0);
         spin_unlock(&irq_2_ir_lock);
-        return 0;
+
+        return rc;
 }
 
 int flush_irte(int irq)
 {
+        int rc;
         int index;
         struct intel_iommu *iommu;
         struct irq_2_iommu *irq_iommu;
@@ -326,10 +328,10 @@ int flush_irte(int irq)
 
         index = irq_iommu->irte_index + irq_iommu->sub_handle;
 
-        qi_flush_iec(iommu, index, irq_iommu->irte_mask);
+        rc = qi_flush_iec(iommu, index, irq_iommu->irte_mask);
         spin_unlock(&irq_2_ir_lock);
 
-        return 0;
+        return rc;
 }
 
 struct intel_iommu *map_ioapic_to_ir(int apic)
@@ -355,6 +357,7 @@ struct intel_iommu *map_dev_to_ir(struct pci_dev *dev)
 
 int free_irte(int irq)
 {
+        int rc = 0;
         int index, i;
         struct irte *irte;
         struct intel_iommu *iommu;
@@ -375,7 +378,7 @@ int free_irte(int irq)
         if (!irq_iommu->sub_handle) {
                 for (i = 0; i < (1 << irq_iommu->irte_mask); i++)
                         set_64bit((unsigned long *)irte, 0);
-                qi_flush_iec(iommu, index, irq_iommu->irte_mask);
+                rc = qi_flush_iec(iommu, index, irq_iommu->irte_mask);
         }
 
         irq_iommu->iommu = NULL;
@@ -385,7 +388,7 @@ int free_irte(int irq)
 
         spin_unlock(&irq_2_ir_lock);
 
-        return 0;
+        return rc;
 }
 
 static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index c4f6c101dbcd..d2e3cbfba14f 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -194,6 +194,7 @@ static inline void dmar_writeq(void __iomem *addr, u64 val)
 /* FSTS_REG */
 #define DMA_FSTS_PPF ((u32)2)
 #define DMA_FSTS_PFO ((u32)1)
+#define DMA_FSTS_IQE (1 << 4)
 #define dma_fsts_fault_record_index(s) (((s) >> 8) & 0xff)
 
 /* FRCD_REG, 32 bits access */
@@ -328,7 +329,7 @@ extern int qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
                           unsigned int size_order, u64 type,
                           int non_present_entry_flush);
 
-extern void qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu);
+extern int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu);
 
 extern void *intel_alloc_coherent(struct device *, size_t, dma_addr_t *, gfp_t);
 extern void intel_free_coherent(struct device *, size_t, void *, dma_addr_t);