qemu: Build command line for virtio-pmem

Now we have everything prepared for generating the command line.
The device alias prefix was chosen to be 'virtiopmem'.

Since virtio-pmem-pci device goes onto PCI bus generating device
alias must have been changed slightly because
qemuAssignDeviceMemoryAlias() might have used DIMM slot number to
generate the alias. This obviously won't work and thus the "old"
way (which includes qemuDomainDeviceAliasIndex()) must be used.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1735375
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>

src/qemu/qemu_alias.c

@@ -466,6 +466,29 @@ qemuAssignDeviceRNGAlias(virDomainDefPtr def,
 }
 
 
+static int
+qemuDeviceMemoryGetAliasID(virDomainDefPtr def,
+                           virDomainMemoryDefPtr mem,
+                           bool oldAlias,
+                           const char *prefix)
+{
+    size_t i;
+    int maxidx = 0;
+
+    /* virtio-pmem goes onto PCI bus and thus DIMM address is not valid */
+    if (!oldAlias && mem->model != VIR_DOMAIN_MEMORY_MODEL_VIRTIO_PMEM)
+        return mem->info.addr.dimm.slot;
+
+    for (i = 0; i < def->nmems; i++) {
+        int idx;
+        if ((idx = qemuDomainDeviceAliasIndex(&def->mems[i]->info, prefix)) >= maxidx)
+            maxidx = idx + 1;
+    }
+
+    return maxidx;
+}
+
+
 /**
  * qemuAssignDeviceMemoryAlias:
  * @def: domain definition. Necessary only if @oldAlias is true.
@@ -483,29 +506,32 @@ qemuAssignDeviceMemoryAlias(virDomainDefPtr def,
                             virDomainMemoryDefPtr mem,
                             bool oldAlias)
 {
-    size_t i;
-    int maxidx = 0;
-    int idx;
-    const char *prefix;
+    const char *prefix = NULL;
+    int idx = 0;
 
     if (mem->info.alias)
         return 0;
 
-    if (mem->model == VIR_DOMAIN_MEMORY_MODEL_DIMM)
+    switch (mem->model) {
+    case VIR_DOMAIN_MEMORY_MODEL_DIMM:
         prefix = "dimm";
-    else
+        break;
+    case VIR_DOMAIN_MEMORY_MODEL_NVDIMM:
         prefix = "nvdimm";
-
-    if (oldAlias) {
-        for (i = 0; i < def->nmems; i++) {
-            if ((idx = qemuDomainDeviceAliasIndex(&def->mems[i]->info, prefix)) >= maxidx)
-                maxidx = idx + 1;
-        }
-    } else {
-        maxidx = mem->info.addr.dimm.slot;
+        break;
+    case VIR_DOMAIN_MEMORY_MODEL_VIRTIO_PMEM:
+        prefix = "virtiopmem";
+        break;
+    case VIR_DOMAIN_MEMORY_MODEL_NONE:
+    case VIR_DOMAIN_MEMORY_MODEL_LAST:
+    default:
+        virReportEnumRangeError(virDomainMemoryModel, mem->model);
+        return -1;
+        break;
     }
 
-    mem->info.alias = g_strdup_printf("%s%d", prefix, maxidx);
+    idx = qemuDeviceMemoryGetAliasID(def, mem, oldAlias, prefix);
+    mem->info.alias = g_strdup_printf("%s%d", prefix, idx);
 
     return 0;
 }
@@ -680,7 +706,7 @@ qemuAssignDeviceAliases(virDomainDefPtr def, virQEMUCapsPtr qemuCaps)
             return -1;
     }
     for (i = 0; i < def->nmems; i++) {
-        if (qemuAssignDeviceMemoryAlias(NULL, def->mems[i], false) < 0)
+        if (qemuAssignDeviceMemoryAlias(def, def->mems[i], false) < 0)
             return -1;
     }
     if (def->vsock) {

src/qemu/qemu_command.c

@@ -3087,8 +3087,9 @@ qemuBuildMemoryBackendProps(virJSONValuePtr *backendProps,
         if (mem->nvdimmPath) {
             memPath = g_strdup(mem->nvdimmPath);
             /* If the NVDIMM is a real device then there's nothing to prealloc.
-             * If anything, we would be only wearing off the device. */
-            if (!mem->nvdimmPmem)
+             * If anything, we would be only wearing off the device.
+             * Similarly, virtio-pmem-pci doesn't need prealloc either. */
+            if (!mem->nvdimmPmem && mem->model != VIR_DOMAIN_MEMORY_MODEL_VIRTIO_PMEM)
                 prealloc = true;
         } else if (useHugepage) {
             if (qemuGetDomainHupageMemPath(priv->driver, def, pagesize, &memPath) < 0)
@@ -3282,7 +3283,7 @@ qemuBuildMemoryDeviceStr(const virDomainDef *def,
                          virQEMUCapsPtr qemuCaps)
 {
     g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
-    const char *device;
+    const char *device = NULL;
 
     if (!mem->info.alias) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
@@ -3291,13 +3292,24 @@ qemuBuildMemoryDeviceStr(const virDomainDef *def,
     }
 
     switch (mem->model) {
-    case VIR_DOMAIN_MEMORY_MODEL_NVDIMM:
     case VIR_DOMAIN_MEMORY_MODEL_DIMM:
-
-        if (mem->model == VIR_DOMAIN_MEMORY_MODEL_DIMM)
         device = "pc-dimm";
-        else
+        break;
+    case VIR_DOMAIN_MEMORY_MODEL_NVDIMM:
         device = "nvdimm";
+        break;
+
+    case VIR_DOMAIN_MEMORY_MODEL_VIRTIO_PMEM:
+        device = "virtio-pmem-pci";
+        break;
+
+    case VIR_DOMAIN_MEMORY_MODEL_NONE:
+    case VIR_DOMAIN_MEMORY_MODEL_LAST:
+    default:
+        virReportEnumRangeError(virDomainMemoryModel, mem->model);
+        return NULL;
+        break;
+    }
 
     virBufferAsprintf(&buf, "%s,", device);
 
@@ -3323,14 +3335,6 @@ qemuBuildMemoryDeviceStr(const virDomainDef *def,
 
     if (qemuBuildDeviceAddressStr(&buf, def, &mem->info, qemuCaps) < 0)
         return NULL;
-        break;
-
-    case VIR_DOMAIN_MEMORY_MODEL_VIRTIO_PMEM:
-    case VIR_DOMAIN_MEMORY_MODEL_NONE:
-    case VIR_DOMAIN_MEMORY_MODEL_LAST:
-        break;
-
-    }
 
     return virBufferContentAndReset(&buf);
 }

tests/qemuxml2argvdata/memory-hotplug-virtio-pmem.x86_64-latest.args

@@ -0,0 +1,45 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/tmp/lib/domain--1-QEMUGuest1 \
+USER=test \
+LOGNAME=test \
+XDG_DATA_HOME=/tmp/lib/domain--1-QEMUGuest1/.local/share \
+XDG_CACHE_HOME=/tmp/lib/domain--1-QEMUGuest1/.cache \
+XDG_CONFIG_HOME=/tmp/lib/domain--1-QEMUGuest1/.config \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-i386 \
+-name guest=QEMUGuest1,debug-threads=on \
+-S \
+-object secret,id=masterKey0,format=raw,\
+file=/tmp/lib/domain--1-QEMUGuest1/master-key.aes \
+-machine pc,accel=kvm,usb=off,dump-guest-core=off \
+-cpu qemu64 \
+-m size=2095104k,slots=16,maxmem=1099511627776k \
+-overcommit mem-lock=off \
+-smp 2,sockets=2,dies=1,cores=1,threads=1 \
+-object memory-backend-ram,id=ram-node0,size=2145386496 \
+-numa node,nodeid=0,cpus=0-1,memdev=ram-node0 \
+-object memory-backend-file,id=memvirtiopmem0,mem-path=/tmp/virtio_pmem,\
+share=yes,size=536870912 \
+-device virtio-pmem-pci,memdev=memvirtiopmem0,id=virtiopmem0,bus=pci.0,\
+addr=0x5 \
+-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,fd=1729,server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown \
+-no-acpi \
+-boot strict=on \
+-device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \
+-blockdev '{"driver":"host_device","filename":"/dev/HostVG/QEMUGuest1",\
+"node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \
+-blockdev '{"node-name":"libvirt-1-format","read-only":false,"driver":"raw",\
+"file":"libvirt-1-storage"}' \
+-device ide-hd,bus=ide.0,unit=0,drive=libvirt-1-format,id=ide0-0-0,bootindex=1 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 \
+-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
+resourcecontrol=deny \
+-msg timestamp=on

tests/qemuxml2argvtest.c

@@ -3053,6 +3053,7 @@ mymain(void)
                  QEMU_CAPS_OBJECT_MEMORY_FILE,
                  QEMU_CAPS_DEVICE_NVDIMM,
                  QEMU_CAPS_LAST);
+    DO_TEST_CAPS_LATEST("memory-hotplug-virtio-pmem");
 
     DO_TEST("machine-aeskeywrap-on-caps",
             QEMU_CAPS_AES_KEY_WRAP,