From: ddugger@redhat.com <ddugger@redhat.com>
Date: Wed, 24 Jun 2009 17:16:21 -0600
Subject: [xen] allow msi reconfigure for pt_bind_irq
Message-id: 200906242316.n5ONGL5w027924@sobek.n0ano.com
O-Subject: [RHEL 5.4 PATCH] BZ 507970: xen: allow msi reconfigure for pt_bind_irq
Bugzilla: 507970
RH-Acked-by: Don Dutile <ddutile@redhat.com>
RH-Acked-by: Justin M. Forbes <jforbes@redhat.com>
RH-Acked-by: Rik van Riel <riel@redhat.com>

backporting xen-unstable c.s. 19548

	changeset:   19548:3e64dfebabd7
	user:        Keir Fraser <keir.fraser@citrix.com>
	date:        Wed Apr 15 15:38:57 2009 +0100
	files:       xen/drivers/passthrough/io.c
	description:
	passthrough: allow pt_bind_irq for msi update

	Extend pt_bind_irq to handle the update of msi guest
	vector and flag.

	Unbind and rebind using separate hypercalls may not be viable
	sometime.
	For example, the guest may update MSI address/data on fly without
	disabling it first (e.g. change delivery/destination), implement these
	updates in such a way may result in interrupt loss.

	Signed-off-by: Qing He <qing.he@intel.com>

Upstream Status: Accepted

Brew build: http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1861081

Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Don Dugger <donald.d.dugger@intel.com>

diff --git a/drivers/passthrough/io.c b/drivers/passthrough/io.c
index a627b99..f62421b 100644
--- a/drivers/passthrough/io.c
+++ b/drivers/passthrough/io.c
@@ -110,12 +110,22 @@ int pt_irq_create_bind_vtd(
                 return rc;
             }
         }
-        else if (hvm_irq_dpci->mirq[pirq].gmsi.gvec != pt_irq_bind->u.msi.gvec
-                ||hvm_irq_dpci->msi_gvec_pirq[pt_irq_bind->u.msi.gvec] != pirq)
-
+        else
         {
-            spin_unlock(&d->event_lock);
-            return -EBUSY;
+            uint32_t old_gvec;
+
+            if ( !test_bit(_HVM_IRQ_DPCI_MSI, &hvm_irq_dpci->mirq[pirq].flags) )
+            {
+	            spin_unlock(&d->event_lock);
+        	    return -EBUSY;
+            }
+
+            /* if pirq is already mapped as vmsi, update the guest data/addr */
+            old_gvec = hvm_irq_dpci->mirq[pirq].gmsi.gvec;
+            hvm_irq_dpci->msi_gvec_pirq[old_gvec] = 0;
+            hvm_irq_dpci->mirq[pirq].gmsi.gvec = pt_irq_bind->u.msi.gvec;
+            hvm_irq_dpci->mirq[pirq].gmsi.gflags = pt_irq_bind->u.msi.gflags;
+            hvm_irq_dpci->msi_gvec_pirq[pt_irq_bind->u.msi.gvec] = pirq;
         }
     }
     else