vt-d: Support intra-domain shared interrupt.

Inter-domain shared interrupt has been supported by timeout method,
but it still doesn't support intra-domain shared interrupt, that is
assigning multiple devices which share a physical irq to the same
domain. This patch implements intra-domain shared interrupt
support. In addition, this patch maps link to guest device/intx
instead of directly mapping isairq in pt_irq_create_bind_vtd(),
because at this point the isairqs got from pci_link are always 0.

Note that assigning multiple devices to guests which uses PIC to
handle interrupts may be failed, because different links possibly
connect to same irq.

Signed-off-by: Weidong Han <weidong.han@intel.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c
index b4f85cb562..ecff77f01f 100644
--- a/xen/arch/x86/hvm/irq.c
+++ b/xen/arch/x86/hvm/irq.c
@@ -192,15 +192,12 @@ void hvm_set_pci_link_route(struct domain *d, u8 link, u8 isa_irq)
     hvm_irq->pci_link.route[link] = isa_irq;
 
     /* PCI pass-through fixup. */
-    if ( hvm_irq->dpci && hvm_irq->dpci->girq[old_isa_irq].valid )
+    if ( hvm_irq->dpci && hvm_irq->dpci->link[link].valid )
     {
-        uint32_t device = hvm_irq->dpci->girq[old_isa_irq].device;
-        uint32_t intx = hvm_irq->dpci->girq[old_isa_irq].intx;
-        if ( link == hvm_pci_intx_link(device, intx) )
-        {
-            hvm_irq->dpci->girq[isa_irq] = hvm_irq->dpci->girq[old_isa_irq];
+        hvm_irq->dpci->girq[isa_irq] = hvm_irq->dpci->link[link];
+        if ( hvm_irq->dpci->girq[old_isa_irq].device ==
+             hvm_irq->dpci->link[link].device )
             hvm_irq->dpci->girq[old_isa_irq].valid = 0;
-        }
     }
 
     if ( hvm_irq->pci_link_assert_count[link] == 0 )