--- a/xen/arch/x86/msi.c
+++ b/xen/arch/x86/msi.c
@@ -207,10 +207,22 @@ static void read_msi_msg(struct msi_desc
 
 static void write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 {
+ if(!(msg->data & MSI_DATA_VECTOR_MASK) || !(msg->data & MSI_DATA_LEVEL_ASSERT)//temp
+    || (msg->data & MSI_DATA_DELIVERY_MODE_MASK) > MSI_DATA_DELIVERY_LOWPRI) {//temp
+  printk("MSI: addr=%08x%08x data=%08x dest=%08x bogus!\n", msg->address_hi, msg->address_lo, msg->data, msg->dest32);
+  dump_execution_state();
+ }
     entry->msg = *msg;
 
     if ( iommu_enabled )
+    {
+        ASSERT(msg != &entry->msg);
         iommu_update_ire_from_msi(entry, msg);
+ if(!(entry->msg.data & MSI_DATA_VECTOR_MASK) || !(entry->msg.data & MSI_DATA_LEVEL_ASSERT)//temp
+    || (entry->msg.data & MSI_DATA_DELIVERY_MODE_MASK) > MSI_DATA_DELIVERY_LOWPRI)//temp
+  printk("MSI: addr=%08x%08x data=%08x dest=%08x (%08x) bogus!\n",//temp
+         entry->msg.address_hi, entry->msg.address_lo, entry->msg.data, entry->msg.dest32, msg->address_lo);//temp
+    }
 
     switch ( entry->msi_attrib.type )
     {
@@ -268,6 +280,11 @@ static void set_msi_affinity(struct irq_
 
     memset(&msg, 0, sizeof(msg));
     read_msi_msg(msi_desc, &msg);
+ if(!(msg.data & MSI_DATA_VECTOR_MASK) || !(msg.data & MSI_DATA_LEVEL_ASSERT)//temp
+    || (msg.data & MSI_DATA_DELIVERY_MODE_MASK) > MSI_DATA_DELIVERY_LOWPRI) {//temp
+  printk("MSI: addr=%08x%08x data=%08x bogus!\n", msg.address_hi, msg.address_lo, msg.data);
+  dump_execution_state();
+ }
 
     msg.data &= ~MSI_DATA_VECTOR_MASK;
     msg.data |= MSI_DATA_VECTOR(desc->arch.vector);
@@ -996,6 +1013,7 @@ int pci_restore_msi_state(struct pci_dev
     int ret;
     struct msi_desc *entry, *tmp;
     struct irq_desc *desc;
+    struct msi_msg msg;
 
     ASSERT(spin_is_locked(&pcidevs_lock));
 
@@ -1024,13 +1042,17 @@ int pci_restore_msi_state(struct pci_dev
             spin_unlock_irqrestore(&desc->lock, flags);
             return -EINVAL;
         }
+printk("MSI[%04x:%02x:%02x:%u]: addr=%08x%08x data=%08x dest=%08x\n",//temp
+       pdev->seg, pdev->bus, PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),//temp
+       entry->msg.address_hi, entry->msg.address_lo, entry->msg.data, entry->msg.dest32);//temp
 
         if ( entry->msi_attrib.type == PCI_CAP_ID_MSI )
             msi_set_enable(pdev, 0);
         else if ( entry->msi_attrib.type == PCI_CAP_ID_MSIX )
             msix_set_enable(pdev, 0);
 
-        write_msi_msg(entry, &entry->msg);
+        msg = entry->msg;
+        write_msi_msg(entry, &msg);
 
         msi_set_mask_bit(desc, entry->msi_attrib.masked);
 
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1040,8 +1040,6 @@ static void dma_msi_mask(struct irq_desc
     unsigned long flags;
     struct iommu *iommu = desc->action->dev_id;
 
-    irq_complete_move(desc);
-
     /* mask it */
     spin_lock_irqsave(&iommu->register_lock, flags);
     dmar_writel(iommu->reg, DMAR_FECTL_REG, DMA_FECTL_IM);
@@ -1054,6 +1052,13 @@ static unsigned int dma_msi_startup(stru
     return 0;
 }
 
+static void dma_msi_ack(struct irq_desc *desc)
+{
+    irq_complete_move(desc);
+    dma_msi_mask(desc);
+    move_masked_irq(desc);
+}
+
 static void dma_msi_end(struct irq_desc *desc, u8 vector)
 {
     dma_msi_unmask(desc);
@@ -1115,7 +1120,7 @@ static hw_irq_controller dma_msi_type = 
     .shutdown = dma_msi_mask,
     .enable = dma_msi_unmask,
     .disable = dma_msi_mask,
-    .ack = dma_msi_mask,
+    .ack = dma_msi_ack,
     .end = dma_msi_end,
     .set_affinity = dma_msi_set_affinity,
 };