qemu: ensure vhostuser FD is initialized to -1

The video private data was not initializing the vhostuser FD
causing us to attempt to close FD 0 many times over.

Fixes

  commit ca60ecfa
  Author: Marc-André Lureau <marcandre.lureau@redhat.com>
  Date:   Mon Sep 23 14:44:36 2019 +0400

      qemu: add qemuDomainVideoPrivate

Since the test suite does not invoke qemuExtDevicesStart(), no
vhost_user_fd will be present when generating test XML. To deal
with this we can must a fake FD number. While the current XML
is using FD == 0, we pick a very interesting number that's unlikely
to be a real FD, so that we're more likely to see any mistakes
closing the invalid FD.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

src/qemu/qemu_domain.c

@@ -1368,6 +1368,8 @@ qemuDomainVideoPrivateNew(void)
     if (!(priv = virObjectNew(qemuDomainVideoPrivateClass)))
         return NULL;
 
+    priv->vhost_user_fd = -1;
+
     return (virObjectPtr) priv;
 }
 

tests/qemuxml2argvdata/vhost-user-gpu-secondary.x86_64-latest.args

@@ -31,8 +31,8 @@ file=/tmp/lib/domain--1-QEMUGuest1/master-key.aes \
 -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \
 -drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \
 -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
--chardev socket,id=chr-vu-video0,fd=0 \
--chardev socket,id=chr-vu-video1,fd=0 \
+-chardev socket,id=chr-vu-video0,fd=1729 \
+-chardev socket,id=chr-vu-video1,fd=1729 \
 -device vhost-user-vga,id=video0,max_outputs=1,chardev=chr-vu-video0,bus=pci.0,\
 addr=0x2 \
 -device vhost-user-gpu-pci,id=video1,max_outputs=1,chardev=chr-vu-video1,\

tests/qemuxml2argvdata/vhost-user-vga.x86_64-latest.args

@@ -31,7 +31,7 @@ file=/tmp/lib/domain--1-QEMUGuest1/master-key.aes \
 -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \
 -drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \
 -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \
--chardev socket,id=chr-vu-video0,fd=0 \
+-chardev socket,id=chr-vu-video0,fd=1729 \
 -device vhost-user-vga,id=video0,max_outputs=1,chardev=chr-vu-video0,bus=pci.0,\
 addr=0x2 \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 \

tests/qemuxml2argvdata/virtio-options.args

@@ -49,7 +49,7 @@ ats=on \
 ats=on \
 -device virtio-input-host-pci,id=input3,evdev=/dev/input/event1234,bus=pci.0,\
 addr=0x12,iommu_platform=on,ats=on \
--chardev socket,id=chr-vu-video0,fd=0 \
+-chardev socket,id=chr-vu-video0,fd=1729 \
 -device vhost-user-gpu-pci,id=video0,max_outputs=1,chardev=chr-vu-video0,\
 bus=pci.0,addr=0x2,iommu_platform=on,ats=on \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xc,iommu_platform=on,\

tests/qemuxml2argvtest.c

@@ -528,6 +528,16 @@ testCompareXMLToArgv(const void *data)
        }
     }
 
+    for (i = 0; i < vm->def->nvideos; i++) {
+        virDomainVideoDefPtr video = vm->def->videos[i];
+
+        if (video->backend == VIR_DOMAIN_VIDEO_BACKEND_TYPE_VHOSTUSER) {
+            qemuDomainVideoPrivatePtr vpriv = QEMU_DOMAIN_VIDEO_PRIVATE(video);
+
+            vpriv->vhost_user_fd = 1729;
+        }
+    }
+
     if (flags & FLAG_SLIRP_HELPER) {
         for (i = 0; i < vm->def->nnets; i++) {
             virDomainNetDefPtr net = vm->def->nets[i];