[Xen-devel] [Patch RFC 13/13] vt-d: Set the IF bit in Invalidation Wait Descriptor When submit Device-TLB

[Quan Xu <quan.xu@xxxxxxxxx>]

invalidataion requests. If the IF bit is Set, the interrupt based mechanism
will be used to track the Device-TLB invalidation requests. Do not do polling
to detect whether hardware completes the Device-TLB invalidation during Device-
TLB invalidation.

Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>
---
 xen/drivers/passthrough/vtd/qinval.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/qinval.c 
b/xen/drivers/passthrough/vtd/qinval.c
index 0d85ce7..b330d02 100644
--- a/xen/drivers/passthrough/vtd/qinval.c
+++ b/xen/drivers/passthrough/vtd/qinval.c
@@ -176,7 +176,15 @@ static int queue_invalidate_wait(struct iommu *iommu,
     qinval_update_qtail(iommu, index);
     spin_unlock_irqrestore(&iommu->register_lock, flags);
 
-    /* Now we don't support interrupt method */
+    /*
+     * If the iflag is Set, the interrupt based mechanism will be used to track
+     * the Device-TLB invalidation status. Do not do polling to detect whether
+     * hardware completes the Device-TLB invalidation during submitting 
Device-TLB
+     * invalidation requests.
+     */
+    if ( iflag )
+        return 0;
+
     if ( sw )
     {
         /* In case all wait descriptor writes to same addr with same data */
@@ -322,6 +330,15 @@ static int flush_context_qi(
     return ret;
 }
 
+static int invalidate_async(struct iommu *iommu, u16 device_id)
+{
+    struct qi_ctrl *qi_ctrl = iommu_qi_ctrl(iommu);
+
+    if ( qi_ctrl->qinval_maddr )
+        return queue_invalidate_wait(iommu, 1, 1, 1, device_id);
+    return 0;
+}
+
 static int flush_iotlb_qi(
     void *_iommu, u16 did,
     u64 addr, unsigned int size_order, u64 type,
@@ -360,8 +377,13 @@ static int flush_iotlb_qi(
                                type >> DMA_TLB_FLUSH_GRANU_OFFSET, dr,
                                dw, did, size_order, 0, addr);
         if ( flush_dev_iotlb )
+        {
             ret = dev_invalidate_iotlb(iommu, did, addr, size_order, type);
-        rc = invalidate_sync(iommu);
+            rc = invalidate_async(iommu, did);
+        } else {
+            rc = invalidate_sync(iommu);
+        }
+
         if ( !ret )
             ret = rc;
     }
-- 
1.8.3.2


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