qemu: Introduce QEMU_CAPS_DEVICE_NVDIMM

Introduce a qemu capability for -device nvdimm.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_capabilities.c

@@ -359,6 +359,7 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
               "query-cpu-model-expansion", /* 245 */
               "virtio-net.host_mtu",
               "spice-rendernode",
+              "nvdimm",
     );
 
 
@@ -1619,6 +1620,7 @@ struct virQEMUCapsStringFlags virQEMUCapsObjectTypes[] = {
     { "ivshmem-plain", QEMU_CAPS_DEVICE_IVSHMEM_PLAIN },
     { "ivshmem-doorbell", QEMU_CAPS_DEVICE_IVSHMEM_DOORBELL },
     { "vhost-scsi", QEMU_CAPS_DEVICE_VHOST_SCSI },
+    { "nvdimm", QEMU_CAPS_DEVICE_NVDIMM },
 };
 
 static struct virQEMUCapsStringFlags virQEMUCapsObjectPropsVirtioBalloon[] = {
@@ -4542,6 +4544,13 @@ virQEMUCapsInitQMPMonitor(virQEMUCapsPtr qemuCaps,
         virQEMUCapsProbeQMPGICCapabilities(qemuCaps, mon) < 0)
         goto cleanup;
 
+    /* Prealloc on NVDIMMs is broken on older QEMUs leading to
+     * user data corruption. If we are dealing with such version
+     * of QEMU pretend we don't know how to NVDIMM. */
+    if (qemuCaps->version < 2009000 &&
+        virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_NVDIMM))
+        virQEMUCapsClear(qemuCaps, QEMU_CAPS_DEVICE_NVDIMM);
+
     ret = 0;
  cleanup:
     return ret;

src/qemu/qemu_capabilities.h

@@ -394,6 +394,7 @@ typedef enum {
     QEMU_CAPS_QUERY_CPU_MODEL_EXPANSION, /* qmp query-cpu-model-expansion */
     QEMU_CAPS_VIRTIO_NET_HOST_MTU, /* virtio-net-*.host_mtu */
     QEMU_CAPS_SPICE_RENDERNODE, /* -spice rendernode */
+    QEMU_CAPS_DEVICE_NVDIMM, /* -device nvdimm */
 
     QEMU_CAPS_LAST /* this must always be the last item */
 } virQEMUCapsFlags;