[PATCH 04/10] qemu: Build command line for virtio-mem

Michal Privoznik mprivozn at redhat.com
Fri Jan 22 12:50:26 UTC 2021


Nothing special is happening here. All important changes were
done when for 'virtio-pmem' (adjusting the code to put virtio
memory on PCI bus, generating alias using
qemuDomainDeviceAliasIndex(). The only bit that might look
suspicious is no prealloc for virtio-mem. But if you think about
it, the whole purpose of this device is to change amount of
memory exposed to guest on the fly. There is no point in locking
the whole backend in memory.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/qemu/qemu_alias.c                         |  9 +++-
 src/qemu/qemu_command.c                       | 12 ++++-
 ...mory-hotplug-virtio-mem.x86_64-latest.args | 49 +++++++++++++++++++
 tests/qemuxml2argvtest.c                      |  1 +
 4 files changed, 68 insertions(+), 3 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/memory-hotplug-virtio-mem.x86_64-latest.args

diff --git a/src/qemu/qemu_alias.c b/src/qemu/qemu_alias.c
index 2a4e2393c8..e539bf9c8e 100644
--- a/src/qemu/qemu_alias.c
+++ b/src/qemu/qemu_alias.c
@@ -475,8 +475,11 @@ qemuDeviceMemoryGetAliasID(virDomainDefPtr def,
     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)
+    /* virtio-pmem and virtio-mem go onto PCI bus and thus DIMM address is not
+     * valid */
+    if (!oldAlias &&
+        mem->model != VIR_DOMAIN_MEMORY_MODEL_VIRTIO_PMEM &&
+        mem->model != VIR_DOMAIN_MEMORY_MODEL_VIRTIO_MEM)
         return mem->info.addr.dimm.slot;
 
     for (i = 0; i < def->nmems; i++) {
@@ -523,6 +526,8 @@ qemuAssignDeviceMemoryAlias(virDomainDefPtr def,
         prefix = "virtiopmem";
         break;
     case VIR_DOMAIN_MEMORY_MODEL_VIRTIO_MEM:
+        prefix = "virtiomem";
+        break;
     case VIR_DOMAIN_MEMORY_MODEL_NONE:
     case VIR_DOMAIN_MEMORY_MODEL_LAST:
     default:
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 0a4a8f2646..4e50dbc0fd 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3094,7 +3094,9 @@ qemuBuildMemoryBackendProps(virJSONValuePtr *backendProps,
         } else if (useHugepage) {
             if (qemuGetDomainHupageMemPath(priv->driver, def, pagesize, &memPath) < 0)
                 return -1;
-            prealloc = true;
+            /* For virtio-mem backed by hugepages we don't need prealloc. */
+            if (mem->model != VIR_DOMAIN_MEMORY_MODEL_VIRTIO_MEM)
+                prealloc = true;
         } else {
             /* We can have both pagesize and mem source. If that's the case,
              * prefer hugepages as those are more specific. */
@@ -3304,6 +3306,9 @@ qemuBuildMemoryDeviceStr(const virDomainDef *def,
         break;
 
     case VIR_DOMAIN_MEMORY_MODEL_VIRTIO_MEM:
+        device = "virtio-mem-pci";
+        break;
+
     case VIR_DOMAIN_MEMORY_MODEL_NONE:
     case VIR_DOMAIN_MEMORY_MODEL_LAST:
     default:
@@ -3320,6 +3325,11 @@ qemuBuildMemoryDeviceStr(const virDomainDef *def,
     if (mem->labelsize)
         virBufferAsprintf(&buf, "label-size=%llu,", mem->labelsize * 1024);
 
+    if (mem->blocksize) {
+        virBufferAsprintf(&buf, "block-size=%llu,", mem->blocksize * 1024);
+        virBufferAsprintf(&buf, "requested-size=%llu,", mem->requestedsize * 1024);
+    }
+
     if (mem->uuid) {
         char uuidstr[VIR_UUID_STRING_BUFLEN];
 
diff --git a/tests/qemuxml2argvdata/memory-hotplug-virtio-mem.x86_64-latest.args b/tests/qemuxml2argvdata/memory-hotplug-virtio-mem.x86_64-latest.args
new file mode 100644
index 0000000000..403e05865f
--- /dev/null
+++ b/tests/qemuxml2argvdata/memory-hotplug-virtio-mem.x86_64-latest.args
@@ -0,0 +1,49 @@
+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-ram,id=memvirtiomem0,size=1073741824 \
+-device virtio-mem-pci,node=0,block-size=2097152,requested-size=536870912,\
+memdev=memvirtiomem0,id=virtiomem0,bus=pci.0,addr=0x2 \
+-object memory-backend-file,id=memvirtiomem1,\
+mem-path=/dev/hugepages2M/libvirt/qemu/-1-QEMUGuest1,size=2147483648,\
+host-nodes=1-3,policy=bind \
+-device virtio-mem-pci,node=0,block-size=2097152,requested-size=1073741824,\
+memdev=memvirtiomem1,id=virtiomem1,bus=pci.0,addr=0x4 \
+-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
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index cf77224fc3..0e261fb321 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -3054,6 +3054,7 @@ mymain(void)
                  QEMU_CAPS_DEVICE_NVDIMM,
                  QEMU_CAPS_LAST);
     DO_TEST_CAPS_LATEST("memory-hotplug-virtio-pmem");
+    DO_TEST_CAPS_LATEST("memory-hotplug-virtio-mem");
 
     DO_TEST("machine-aeskeywrap-on-caps",
             QEMU_CAPS_AES_KEY_WRAP,
-- 
2.26.2




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