[Xen-devel] [PATCH v4 5/6] VT-d: No need to set irq affinity for posted format IRTE

[Feng Wu <feng.wu@xxxxxxxxx>]

We don't set the affinity for posted format IRTE, since the
destination of these interrupts is vCPU and the vCPU affinity
is set during vCPU scheduling.

Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
---
v4:
- Keep the construction of new_ire and only modify the hardware
IRTE when it is not in posted mode.

 xen/drivers/passthrough/vtd/intremap.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/intremap.c 
b/xen/drivers/passthrough/vtd/intremap.c
index bfd468b..4537714 100644
--- a/xen/drivers/passthrough/vtd/intremap.c
+++ b/xen/drivers/passthrough/vtd/intremap.c
@@ -637,9 +637,12 @@ static int msi_msg_to_remap_entry(
     remap_rte->address_hi = 0;
     remap_rte->data = index - i;
 
-    memcpy(iremap_entry, &new_ire, sizeof(struct iremap_entry));
-    iommu_flush_cache_entry(iremap_entry, sizeof(struct iremap_entry));
-    iommu_flush_iec_index(iommu, 0, index);
+    if ( !iremap_entry->remap.p || !iremap_entry->remap.im )
+    {
+        memcpy(iremap_entry, &new_ire, sizeof(struct iremap_entry));
+        iommu_flush_cache_entry(iremap_entry, sizeof(struct iremap_entry));
+        iommu_flush_iec_index(iommu, 0, index);
+    }
 
     unmap_vtd_domain_page(iremap_entries);
     spin_unlock_irqrestore(&ir_ctrl->iremap_lock, flags);
-- 
2.1.0


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