From 4ec18f1f504556545e497ff1338bc23be4ced00b Mon Sep 17 00:00:00 2001
Message-Id: <4ec18f1f504556545e497ff1338bc23be4ced00b.1341315334.git.minovotn@redhat.com>
From: Don Dutile <ddutile@redhat.com>
Date: Thu, 21 Jun 2012 20:32:53 +0200
Subject: [PATCH 1/2] kvm: dev-assignment: tag pci dev when assigned to guest

RH-Author: Don Dutile <ddutile@redhat.com>
Message-id: <1340310773-62228-1-git-send-email-ddutile@redhat.com>
Patchwork-id: 40061
O-Subject: [RHEL5 PATCH] kvm: dev-assignment: tag pci dev when assigned to guest
Bugzilla: 784899
RH-Acked-by: Alex Williamson <alex.williamson@redhat.com>
RH-Acked-by: Stefan Assmann <sassmann@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>

Backport of kvm portion of upstream
commit 6777829cfe1c4ed78319ad40aaee60254222da76
Upstream description:

     Author: Greg Rose <gregory.v.rose@intel.com>
     Date:   Fri Jul 22 05:46:07 2011 +0000

     pci: Add flag indicating device has been assigned by KVM

     Device drivers that create and destroy SR-IOV virtual functions via
     calls to pci_enable_sriov() and pci_disable_sriov can cause catastrophic
     failures if they attempt to destroy VFs while they are assigned to
     guest virtual machines.  By adding a flag for use by the KVM module
     to indicate that a device is assigned a device driver can check that
     flag and avoid destroying VFs while they are assigned and avoid system
     failures.

Backport of kvm portion of RHEL6
commit cc8bde656a9ecdb97aaa8e3723a5140f9bd01af7

RH Bugzilla 784899.

Brew-build:
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=4504589
(brew build results gone now; I saved the rpms if interested to try)

Note: the kvm.spec file requires the kernel version to be changed
      to 2.6.18-317, minimum; the brew build is against -318.
      -- Not sure if I submit a spec file patch to make that happen,
         or is this note sufficient to start another process to
         change the package's spec file.
         -- I had to get dist-5E-test updated to -318 to enable
            the brew build to work with an updated kvm.spec file.

Testing:
The rhel5 igb[vf] and ixgbe[vf] drivers need to be updated
to test that this patch enables the resolution of the (upstream)
described problem.
Stefan Assmann & Andy Gospodarek are working those backports, resp.,
and I am awaiting their testing results.  Posting now to get
initial ack's, even if they are contingent on test results.

Please review and ack.
---
 virt/kvm/iommu.c    | 4 ++++
 virt/kvm/kvm_main.c | 2 ++
 2 files changed, 6 insertions(+)

Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
 virt/kvm/iommu.c    |    4 ++++
 virt/kvm/kvm_main.c |    2 ++
 2 files changed, 6 insertions(+)

diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 17aed9b..3e70943 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -107,6 +107,8 @@ int kvm_assign_device(struct kvm *kvm,
 		return r;
 	}
 
+	pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
+
 	printk(KERN_DEBUG "assign device: host bdf = %x:%x:%x\n",
 		assigned_dev->host_busnr,
 		PCI_SLOT(assigned_dev->host_devfn),
@@ -131,6 +133,8 @@ int kvm_deassign_device(struct kvm *kvm,
 
 	iommu_detach_device(domain, &pdev->dev);
 
+	pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
+
 	printk(KERN_DEBUG "deassign device: host bdf = %x:%x:%x\n",
 		assigned_dev->host_busnr,
 		PCI_SLOT(assigned_dev->host_devfn),
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 40b9328..469be3d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -313,6 +313,8 @@ static void kvm_free_assigned_device(struct kvm *kvm,
 
 	pci_reset_function(assigned_dev->dev);
 
+	assigned_dev->dev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
+
 	pci_release_regions(assigned_dev->dev);
 	pci_disable_device(assigned_dev->dev);
 	pci_dev_put(assigned_dev->dev);
-- 
1.7.10.4