[Xen-devel] [PATCH] VT-d: return full destination ID for IO-APIC reads

["Jan Beulich" <JBeulich@xxxxxxxx>]

In x2APIC mode it is 32 bits wide. Not having returned the full value
was mostly benign: We never modify the ID based on its original value;
full new values get written at all times. It was "just" debug logging
which ended up wrong this way (and which will need adjustment itself as
well, to also consume the full value).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/drivers/passthrough/vtd/intremap.c
+++ b/xen/drivers/passthrough/vtd/intremap.c
@@ -314,8 +314,13 @@ static int remap_entry_to_ioapic_rte(
     old_rte->dest_mode = iremap_entry->remap.dm;
     old_rte->trigger = iremap_entry->remap.tm;
     old_rte->__reserved_2 = 0;
-    old_rte->dest.logical.__reserved_1 = 0;
-    old_rte->dest.logical.logical_dest = iremap_entry->remap.dst >> 8;
+    if ( x2apic_enabled )
+        old_rte->dest.dest32 = iremap_entry->remap.dst;
+    else
+    {
+        old_rte->dest.logical.__reserved_1 = 0;
+        old_rte->dest.logical.logical_dest = iremap_entry->remap.dst >> 8;
+    }
 
     unmap_vtd_domain_page(iremap_entries);
     spin_unlock_irqrestore(&ir_ctrl->iremap_lock, flags);



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