VT-d: don't suppress invalidation address write when it is zero

GFN zero is a valid address, and hence may need invalidation done for
it just like for any other GFN.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Yang Zhang <yang.z.zhang@intel.com>

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 82549376cfa64f311c0981bdd74418a0295d3ff9..d95f4d4720c86e7797bc2e1525bdfa07c98c0859 100644 (file)
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -414,7 +414,7 @@ static int flush_iotlb_reg(void *_iommu, u16 did,
 {
     struct iommu *iommu = (struct iommu *) _iommu;
     int tlb_offset = ecap_iotlb_offset(iommu->ecap);
-    u64 val = 0, val_iva = 0;
+    u64 val = 0;
     unsigned long flags;
 
     /*
@@ -435,7 +435,6 @@ static int flush_iotlb_reg(void *_iommu, u16 did,
     switch ( type )
     {
     case DMA_TLB_GLOBAL_FLUSH:
-        /* global flush doesn't need set IVA_REG */
         val = DMA_TLB_GLOBAL_FLUSH|DMA_TLB_IVT;
         break;
     case DMA_TLB_DSI_FLUSH:
@@ -443,8 +442,6 @@ static int flush_iotlb_reg(void *_iommu, u16 did,
         break;
     case DMA_TLB_PSI_FLUSH:
         val = DMA_TLB_PSI_FLUSH|DMA_TLB_IVT|DMA_TLB_DID(did);
-        /* Note: always flush non-leaf currently */
-        val_iva = size_order | addr;
         break;
     default:
         BUG();
@@ -457,8 +454,11 @@ static int flush_iotlb_reg(void *_iommu, u16 did,
 
     spin_lock_irqsave(&iommu->register_lock, flags);
     /* Note: Only uses first TLB reg currently */
-    if ( val_iva )
-        dmar_writeq(iommu->reg, tlb_offset, val_iva);
+    if ( type == DMA_TLB_PSI_FLUSH )
+    {
+        /* Note: always flush non-leaf currently. */
+        dmar_writeq(iommu->reg, tlb_offset, size_order | addr);
+    }
     dmar_writeq(iommu->reg, tlb_offset + 8, val);
 
     /* Make sure hardware complete it */