From 9f13c7165566f442484fa6c335950465ed6a2050 Mon Sep 17 00:00:00 2001

From: Cornelia Huck <cohuck@redhat.com>

Date: Wed, 17 Apr 2019 13:57:38 +0100

Subject: [PATCH 21/24] s390x/pci: Warn when adding PCI devices without the

 'zpci' feature

RH-Author: Cornelia Huck <cohuck@redhat.com>

Message-id: <20190417135741.25297-22-cohuck@redhat.com>

Patchwork-id: 85803

O-Subject: [RHEL-8.1.0 qemu-kvm PATCH v2 21/24] s390x/pci: Warn when adding PCI devices without the 'zpci' feature

Bugzilla: 1699070

RH-Acked-by: David Hildenbrand <david@redhat.com>

RH-Acked-by: Thomas Huth <thuth@redhat.com>

RH-Acked-by: Jens Freimann <jfreimann@redhat.com>

From: David Hildenbrand <david@redhat.com>

We decided to always create the PCI host bridge, even if 'zpci' is not

enabled (due to migration compatibility). This however right now allows

to add zPCI/PCI devices to a VM although the guest will never actually see

them, confusing people that are using a simple CPU model that has no

'zpci' enabled - "Why isn't this working" (David Hildenbrand)

Let's check for 'zpci' and at least print a warning that this will not

work as expected. We could also bail out, however that might break

existing QEMU commandlines.

Reviewed-by: Thomas Huth <thuth@redhat.com>

Signed-off-by: David Hildenbrand <david@redhat.com>

Message-Id: <20190130155733.32742-4-david@redhat.com>

Reviewed-by: Collin Walling <walling@linux.ibm.com>

Signed-off-by: Cornelia Huck <cohuck@redhat.com>

(cherry picked from commit 703fef6fcf3edcbf169c90b6196fcf88f9e9765a)

Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 hw/s390x/s390-pci-bus.c | 6 ++++++

 1 file changed, 6 insertions(+)

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c

index a0f7245..1ba7873 100644

--- a/hw/s390x/s390-pci-bus.c

+++ b/hw/s390x/s390-pci-bus.c

@@ -864,6 +864,12 @@ static void s390_pcihost_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,

 {

     S390pciState *s = S390_PCI_HOST_BRIDGE(hotplug_dev);

+    if (!s390_has_feat(S390_FEAT_ZPCI)) {

+        warn_report("Plugging a PCI/zPCI device without the 'zpci' CPU "

+                    "feature enabled; the guest will not be able to see/use "

+                    "this device");

+    }

+

     if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {

         PCIDevice *pdev = PCI_DEVICE(dev);

-- 

1.8.3.1