[libvirt] [PATCH 4/4] qemu: Allow use of iothreads for disk definitions

John Ferlan jferlan at redhat.com
Tue Aug 26 00:38:09 UTC 2014


For virtio-blk-pci disks with the disk iothread attribute that are
running the correct emulator, add the "iothread=libvirtIothread#" to
the -device command line in order to enable iothreads for the disk.

This code will check both the "start" and "hotplug" paths for the capability,
whether the iothreadsmap has been defined, and whether there's an available
iothread to be used for the disk.

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 src/qemu/qemu_command.c                            | 35 +++++++++++++++++++
 src/qemu/qemu_command.h                            |  5 +++
 src/qemu/qemu_hotplug.c                            | 11 ++++++
 .../qemuxml2argv-iothreads-disk.args               | 17 +++++++++
 .../qemuxml2argv-iothreads-disk.xml                | 40 ++++++++++++++++++++++
 tests/qemuxml2argvtest.c                           |  2 ++
 tests/qemuxml2xmltest.c                            |  1 +
 7 files changed, 111 insertions(+)
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.args
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.xml

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 287a3f3..740b6ec 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3862,6 +3862,9 @@ qemuBuildDriveDevStr(virDomainDefPtr def,
             virBufferAddLit(&opt, "virtio-blk-device");
         } else {
             virBufferAddLit(&opt, "virtio-blk-pci");
+            if (disk->iothread > 0)
+                virBufferAsprintf(&opt, ",iothread=libvirtIothread%u",
+                                  disk->iothread);
         }
         qemuBuildIoEventFdStr(&opt, disk->ioeventfd, qemuCaps);
         if (disk->event_idx &&
@@ -6614,6 +6617,31 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
 }
 
 
+bool
+qemuDomainIothreadsAvailable(virDomainDefPtr def,
+                             virQEMUCapsPtr qemuCaps,
+                             virDomainDiskDefPtr disk)
+{
+    bool inuse;
+    const char *src = virDomainDiskGetSource(disk);
+
+    if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_IOTHREAD) ||
+        !def->iothreadmap) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("IOThreads not supported for this QEMU "
+                         "for disk '%s'"), src);
+        return false;
+    }
+    if (virBitmapGetBit(def->iothreadmap, disk->iothread, &inuse) || inuse) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("IOThread '%u' for disk '%s' is already "
+                         "being used"), disk->iothread, src);
+        return false;
+    }
+    return true;
+}
+
+
 static int
 qemuBuildGraphicsVNCCommandLine(virQEMUDriverConfigPtr cfg,
                                 virCommandPtr cmd,
@@ -8055,6 +8083,13 @@ qemuBuildCommandLine(virConnectPtr conn,
                            disk->src->driverName, disk->src->path);
             goto error;
         }
+
+        /* Check iothreads relationship */
+        if (disk->iothread > 0) {
+            if (!qemuDomainIothreadsAvailable(def, qemuCaps, disk))
+                goto error;
+            ignore_value(virBitmapSetBit(def->iothreadmap, disk->iothread));
+        }
     }
 
     if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE)) {
diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
index 633ff71..bec6c14 100644
--- a/src/qemu/qemu_command.h
+++ b/src/qemu/qemu_command.h
@@ -81,6 +81,11 @@ virCommandPtr qemuBuildCommandLine(virConnectPtr conn,
                                    bool forXMLToArgv)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(11);
 
+bool
+qemuDomainIothreadsAvailable(virDomainDefPtr def,
+                             virQEMUCapsPtr qemuCaps,
+                             virDomainDiskDefPtr disk);
+
 /* Generate '-device' string for chardev device */
 int
 qemuBuildChrDeviceStr(char **deviceStr,
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index a364c52..720220d 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -335,6 +335,11 @@ qemuDomainAttachVirtioDiskDevice(virConnectPtr conn,
         }
     }
 
+    if (disk->iothread > 0) {
+        if (!qemuDomainIothreadsAvailable(vm->def, priv->qemuCaps, disk))
+            goto cleanup;
+    }
+
     if (qemuDomainPrepareDisk(driver, vm, disk, NULL, false) < 0)
         goto cleanup;
 
@@ -396,6 +401,9 @@ qemuDomainAttachVirtioDiskDevice(virConnectPtr conn,
     if (ret < 0)
         goto error;
 
+    if (disk->iothread && vm->def->iothreadmap)
+        ignore_value(virBitmapSetBit(vm->def->iothreadmap, disk->iothread));
+
     virDomainDiskInsertPreAlloced(vm->def, disk);
 
  cleanup:
@@ -2539,6 +2547,9 @@ qemuDomainRemoveDiskDevice(virQEMUDriverPtr driver,
         }
     }
 
+    if (disk->iothread && vm->def->iothreadmap)
+        ignore_value(virBitmapClearBit(vm->def->iothreadmap, disk->iothread));
+
     qemuDomainReleaseDeviceAddress(vm, &disk->info, src);
 
     if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.args b/tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.args
new file mode 100644
index 0000000..693cb4c
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.args
@@ -0,0 +1,17 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \
+/usr/bin/qemu -S -M \
+pc -m 214 -smp 2 \
+-object iothread,id=libvirtIothread1 \
+-object iothread,id=libvirtIothread2 \
+-nographic -nodefaults -monitor \
+unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -usb \
+-drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-ide0-0-0 \
+-device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \
+-drive file=/var/lib/libvirt/images/iothrtest1.img,if=none,\
+id=drive-virtio-disk1 \
+-device virtio-blk-pci,iothread=libvirtIothread1,bus=pci.0,addr=0x4,\
+drive=drive-virtio-disk1,id=virtio-disk1 \
+-drive file=/var/lib/libvirt/images/iothrtest2.img,if=none,\
+id=drive-virtio-disk2 \
+-device virtio-blk-pci,iothread=libvirtIothread2,bus=pci.0,addr=0x3,\
+drive=drive-virtio-disk2,id=virtio-disk2
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.xml b/tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.xml
new file mode 100644
index 0000000..72122fb
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-iothreads-disk.xml
@@ -0,0 +1,40 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>2</vcpu>
+  <iothreads>2</iothreads>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='raw' iothread='1'/>
+      <source file='/var/lib/libvirt/images/iothrtest1.img'/>
+      <target dev='vdb' bus='virtio'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
+    </disk>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='raw' iothread='2'/>
+      <source file='/var/lib/libvirt/images/iothrtest2.img'/>
+      <target dev='vdc' bus='virtio'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 0e3f60a..0bb282d 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -1183,6 +1183,8 @@ mymain(void)
     DO_TEST("smp", QEMU_CAPS_SMP_TOPOLOGY);
 
     DO_TEST("iothreads", QEMU_CAPS_OBJECT_IOTHREAD);
+    DO_TEST("iothreads-disk", QEMU_CAPS_OBJECT_IOTHREAD, QEMU_CAPS_DEVICE,
+            QEMU_CAPS_DRIVE);
 
     DO_TEST("cpu-topology1", QEMU_CAPS_SMP_TOPOLOGY);
     DO_TEST("cpu-topology2", QEMU_CAPS_SMP_TOPOLOGY);
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index 47314e3..bc345c9 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -299,6 +299,7 @@ mymain(void)
 
     DO_TEST("smp");
     DO_TEST("iothreads");
+    DO_TEST("iothreads-disk");
     DO_TEST("lease");
     DO_TEST("event_idx");
     DO_TEST("vhost_queues");
-- 
1.9.3




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