qemu: Allow creating ppc64 guests with graphics and no USB mouse

The existing behavior for ppc64 guests is to always add a USB
keyboard and mouse combo if graphics are present; unfortunately,
this means any attempt to use a USB tablet will cause both pointing
devices to show up in the guest, which in turn will result in poor
user experience.

We can't just stop adding the USB mouse or start adding a USB tablet
instead, because existing applications and users might rely on the
current behavior; however, we can avoid adding the USB mouse if a USB
tablet is already present, thus allowing users and applications to
create guests that contain a single pointing device.

https://bugzilla.redhat.com/show_bug.cgi?id=1683681

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 5cb5ac801f5f791ff2d3d681c4ec39d35645ad6e..1659e8847869f01a28946a4cff5477fe4a8ecbbd 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -3474,6 +3474,26 @@ qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
         virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_S390) && def->memballoon)
         def->memballoon->model = VIR_DOMAIN_MEMBALLOON_MODEL_NONE;
 
+    if (addDefaultUSBMouse) {
+        bool hasUSBTablet = false;
+        size_t j;
+
+        for (j = 0; j < def->ninputs; j++) {
+            if (def->inputs[j]->type == VIR_DOMAIN_INPUT_TYPE_TABLET &&
+                def->inputs[j]->bus == VIR_DOMAIN_INPUT_BUS_USB) {
+                hasUSBTablet = true;
+                break;
+            }
+        }
+
+        /* Historically, we have automatically added USB keyboard and
+         * mouse to some guests. While the former device is generally
+         * safe to have, adding the latter is undesiderable if a USB
+         * tablet is already present in the guest */
+        if (hasUSBTablet)
+            addDefaultUSBMouse = false;
+    }
+
     if (addDefaultUSBKBD &&
         def->ngraphics > 0 &&
         virDomainDefMaybeAddInput(def,

diff --git a/tests/qemuxml2argvdata/ppc64-pseries-graphics.ppc64-latest.args b/tests/qemuxml2argvdata/ppc64-pseries-graphics.ppc64-latest.args
index 1c6c25ed24d4923c624a69f2f8c38b543538782a..b81648f07815d3a31cff37bb304d588e15faded7 100644 (file)
--- a/tests/qemuxml2argvdata/ppc64-pseries-graphics.ppc64-latest.args
+++ b/tests/qemuxml2argvdata/ppc64-pseries-graphics.ppc64-latest.args
@@ -37,7 +37,6 @@ addr=0x1 \
 id=channel0,name=org.qemu.guest_agent.0 \
 -device usb-tablet,id=input0,bus=usb.0,port=1 \
 -device usb-kbd,id=input1,bus=usb.0,port=2 \
--device usb-mouse,id=input2,bus=usb.0,port=3 \
 -vnc 127.0.0.1:0 \
 -device VGA,id=video0,vgamem_mb=16,bus=pci.0,addr=0x7 \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 \