[PULL 2/5] s390x/s390-virtio-ccw: Switch off zPCI enhancements on older machines

[Thomas Huth <thuth@redhat.com>]

From: Cédric Le Goater <clg@redhat.com>

zPCI enhancement features (interpretation and forward assist) were
recently introduced to improve performance on PCI passthrough devices.
To maintain the same behaviour on older Z machines, deactivate the
features with the associated properties.

Signed-off-by: Cédric Le Goater <clg@redhat.com>
Message-Id: <20221107161349.1032730-3-clg@kaod.org>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 hw/s390x/s390-virtio-ccw.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index bb98d40792..7d80bc1837 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -844,9 +844,14 @@ static void ccw_machine_7_1_instance_options(MachineState *machine)
 static void ccw_machine_7_1_class_options(MachineClass *mc)
 {
     S390CcwMachineClass *s390mc = S390_CCW_MACHINE_CLASS(mc);
+    static GlobalProperty compat[] = {
+        { TYPE_S390_PCI_DEVICE, "interpret", "off", },
+        { TYPE_S390_PCI_DEVICE, "forwarding-assist", "off", },
+    };
 
     ccw_machine_7_2_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_7_1, hw_compat_7_1_len);
+    compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));
     s390mc->max_threads = S390_MAX_CPUS;
 }
 DEFINE_CCW_MACHINE(7_1, "7.1", false);
-- 
2.31.1