diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 3ec1173c6f..6707744bda 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -5456,7 +5456,12 @@ qemu-kvm -net nic,model=? /dev/null
some restrictions on actual value. For instance, latest
QEMU (as of 2016-09-01) requires value to be a power of two
from [256, 1024] range.
- Since 2.3.0 (QEMU and KVM only)
+ Since 2.3.0 (QEMU and KVM only)
+ Additionally, since 4.1.0 the
+ value can be set in the qemu.conf file in order
+ to override the hypervisor default value. Note that XML has
+ higher precedence because it's more specific.
+
In general you should leave this option alone, unless you
are very certain you know what you are doing.
@@ -5472,7 +5477,12 @@ qemu-kvm -net nic,model=? /dev/null
range. In addition to that, this may work only for a subset of
interface types, e.g. aforementioned QEMU enables this option
only for vhostuser type.
- Since 3.7.0 (QEMU and KVM only)
+ Since 3.7.0 (QEMU and KVM only)
+ Additionally, since 4.1.0 the
+ value can be set in the qemu.conf file in order
+ to override the hypervisor default value. Note that XML has
+ higher precedence because it's more specific.
+
In general you should leave this option alone, unless you
are very certain you know what you are doing.
diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug
index c19bf3a43a..084290296a 100644
--- a/src/qemu/libvirtd_qemu.aug
+++ b/src/qemu/libvirtd_qemu.aug
@@ -118,6 +118,9 @@ module Libvirtd_qemu =
let vxhs_entry = bool_entry "vxhs_tls"
| str_entry "vxhs_tls_x509_cert_dir"
+ let virtio_entry = int_entry "rx_queue_size"
+ | int_entry "tx_queue_size"
+
(* Each entry in the config is one of the following ... *)
let entry = default_tls_entry
| vnc_entry
@@ -137,6 +140,7 @@ module Libvirtd_qemu =
| gluster_debug_level_entry
| memory_entry
| vxhs_entry
+ | virtio_entry
let comment = [ label "#comment" . del /#[ \t]*/ "# " . store /([^ \t\n][^\n]*)?/ . del /\n/ "\n" ]
let empty = [ label "#empty" . eol ]
diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf
index 43dd561cca..62c4265ea9 100644
--- a/src/qemu/qemu.conf
+++ b/src/qemu/qemu.conf
@@ -775,3 +775,9 @@
# This directory is used for memoryBacking source if configured as file.
# NOTE: big files will be stored here
#memory_backing_dir = "/var/lib/libvirt/qemu/ram"
+
+# The following two values set the default RX/TX ring buffer size for virtio
+# interfaces. These values are taken unless overridden in domain XML. For more
+# info consult docs to corresponding attributes from domain XML.
+#rx_queue_size = 1024
+#tx_queue_size = 1024
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 899f0cbbbf..5432700287 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3751,7 +3751,8 @@ qemuBuildNicStr(virDomainNetDefPtr net,
char *
-qemuBuildNicDevStr(virDomainDefPtr def,
+qemuBuildNicDevStr(virQEMUDriverConfigPtr cfg,
+ virDomainDefPtr def,
virDomainNetDefPtr net,
int vlan,
unsigned int bootindex,
@@ -3871,21 +3872,41 @@ qemuBuildNicDevStr(virDomainDefPtr def,
virBufferAsprintf(&buf, ",mq=on,vectors=%zu", 2 * vhostfdSize + 2);
}
}
- if (usingVirtio && net->driver.virtio.rx_queue_size) {
- if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_NET_RX_QUEUE_SIZE)) {
- virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
- _("virtio rx_queue_size option is not supported with this QEMU binary"));
- goto error;
+ if (usingVirtio) {
+ unsigned int rx_queue_size = net->driver.virtio.rx_queue_size;
+
+ if (rx_queue_size == 0)
+ rx_queue_size = cfg->rx_queue_size;
+
+ if (rx_queue_size) {
+ if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_NET_RX_QUEUE_SIZE)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("virtio rx_queue_size option is "
+ "not supported with this QEMU binary"));
+ goto error;
+ }
+
+ net->driver.virtio.rx_queue_size = rx_queue_size;
+ virBufferAsprintf(&buf, ",rx_queue_size=%u", rx_queue_size);
}
- virBufferAsprintf(&buf, ",rx_queue_size=%u", net->driver.virtio.rx_queue_size);
}
- if (usingVirtio && net->driver.virtio.tx_queue_size) {
- if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_NET_TX_QUEUE_SIZE)) {
- virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
- _("virtio tx_queue_size option is not supported with this QEMU binary"));
- goto error;
+ if (usingVirtio) {
+ unsigned int tx_queue_size = net->driver.virtio.tx_queue_size;
+
+ if (tx_queue_size == 0)
+ tx_queue_size = cfg->tx_queue_size;
+
+ if (tx_queue_size) {
+ if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_NET_TX_QUEUE_SIZE)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("virtio tx_queue_size option is "
+ "not supported with this QEMU binary"));
+ goto error;
+ }
+
+ net->driver.virtio.tx_queue_size = tx_queue_size;
+ virBufferAsprintf(&buf, ",tx_queue_size=%u", tx_queue_size);
}
- virBufferAsprintf(&buf, ",tx_queue_size=%u", net->driver.virtio.tx_queue_size);
}
if (usingVirtio && net->mtu) {
@@ -8571,7 +8592,7 @@ qemuBuildVhostuserCommandLine(virQEMUDriverPtr driver,
virCommandAddArg(cmd, netdev);
VIR_FREE(netdev);
- if (!(nic = qemuBuildNicDevStr(def, net, -1, bootindex,
+ if (!(nic = qemuBuildNicDevStr(cfg, def, net, -1, bootindex,
queues, qemuCaps))) {
virReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("Error generating NIC -device string"));
@@ -8608,6 +8629,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
int **nicindexes,
bool chardevStdioLogd)
{
+ virQEMUDriverConfigPtr cfg = NULL;
int ret = -1;
char *nic = NULL, *host = NULL;
int *tapfd = NULL;
@@ -8669,6 +8691,8 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
return -1;
}
+ cfg = virQEMUDriverGetConfig(driver);
+
switch (actualType) {
case VIR_DOMAIN_NET_TYPE_NETWORK:
case VIR_DOMAIN_NET_TYPE_BRIDGE:
@@ -8864,7 +8888,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
virCommandAddArgList(cmd, "-netdev", host, NULL);
}
if (qemuDomainSupportsNicdev(def, net)) {
- if (!(nic = qemuBuildNicDevStr(def, net, vlan, bootindex,
+ if (!(nic = qemuBuildNicDevStr(cfg, def, net, vlan, bootindex,
vhostfdSize, qemuCaps)))
goto cleanup;
virCommandAddArgList(cmd, "-device", nic, NULL);
@@ -8908,6 +8932,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
VIR_FREE(host);
VIR_FREE(tapfdName);
VIR_FREE(vhostfdName);
+ virObjectUnref(cfg);
return ret;
}
diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
index 31c9da673c..6449883291 100644
--- a/src/qemu/qemu_command.h
+++ b/src/qemu/qemu_command.h
@@ -90,7 +90,8 @@ char *qemuBuildNicStr(virDomainNetDefPtr net,
int vlan);
/* Current, best practice */
-char *qemuBuildNicDevStr(virDomainDefPtr def,
+char *qemuBuildNicDevStr(virQEMUDriverConfigPtr cfg,
+ virDomainDefPtr def,
virDomainNetDefPtr net,
int vlan,
unsigned int bootindex,
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index af503d31cb..2fa96431fa 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -912,6 +912,10 @@ int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
if (virConfGetValueString(conf, "memory_backing_dir", &cfg->memoryBackingDir) < 0)
goto cleanup;
+ if (virConfGetValueUInt(conf, "rx_queue_size", &cfg->rx_queue_size) < 0 ||
+ virConfGetValueUInt(conf, "tx_queue_size", &cfg->tx_queue_size) < 0)
+ goto cleanup;
+
ret = 0;
cleanup:
diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index a553e30e2e..3f38a76c26 100644
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -206,6 +206,9 @@ struct _virQEMUDriverConfig {
bool vxhsTLS;
char *vxhsTLSx509certdir;
+
+ unsigned int rx_queue_size;
+ unsigned int tx_queue_size;
};
/* Main driver state */
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 5be3e0659a..a8979db2e8 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1120,7 +1120,7 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
for (i = 0; i < vhostfdSize; i++)
VIR_FORCE_CLOSE(vhostfd[i]);
- if (!(nicstr = qemuBuildNicDevStr(vm->def, net, vlan, 0,
+ if (!(nicstr = qemuBuildNicDevStr(cfg, vm->def, net, vlan, 0,
queueSize, priv->qemuCaps)))
goto try_remove;
diff --git a/src/qemu/test_libvirtd_qemu.aug.in b/src/qemu/test_libvirtd_qemu.aug.in
index 688e5b9fda..4fc4e2f4ec 100644
--- a/src/qemu/test_libvirtd_qemu.aug.in
+++ b/src/qemu/test_libvirtd_qemu.aug.in
@@ -100,3 +100,5 @@ module Test_libvirtd_qemu =
{ "1" = "mount" }
}
{ "memory_backing_dir" = "/var/lib/libvirt/qemu/ram" }
+{ "rx_queue_size" = "1024" }
+{ "tx_queue_size" = "1024" }