diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 9f7a1133d1..84b1cab84f 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1378,6 +1378,56 @@ qemu-kvm -net nic,model=? /dev/null ne2k_isa i82551 i82557b i82559er ne2k_pci pcnet rtl8139 e1000 virtio

+
Setting NIC driver-specific options
+ +
+  ...
+  <devices>
+    <interface type='network'>
+      <source network='default'/>
+      <target dev='vnet1'/>
+      <model type='virtio'/>
+      <driver txmode='iothread'/>
+    </interface>
+  </devices>
+  ...
+ +

+ Some NICs may have tunable driver-specific options. These are + set as attributes of the driver sub-element of the + interface definition. Currently the following attributes are + available for the "virtio" NIC driver: +

+ +
+
txmode
+
+ The txmode attribute specifies how to handle + transmission of packets when the transmit buffer is full. The + value can be either 'iothread' or 'timer'. + Since 0.8.8 (QEMU and KVM only)

+ + If set to 'iothread', packet tx is all done in an iothread in + the bottom half of the driver (this option translates into + adding "tx=bh" to the qemu commandline -device virtio-net-pci + option).

+ + If set to 'timer', tx work is done in qemu, and if there is + more tx data than can be sent at the present time, a timer is + set before qemu moves on to do other things; when the timer + fires, another attempt is made to send more data.

+ + The resulting difference, according to the qemu developer who + added the option is: "bh makes tx more asynchronous and reduces + latency, but potentially causes more processor bandwidth + contention since the cpu doing the tx isn't necessarily the + cpu where the guest generated the packets."

+ + In general you should leave this option alone, unless you + are very certain you know what you are doing. +
+
+
Overriding the target element
diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng
index 7fe66e3c26..8b215f35df 100644
--- a/docs/schemas/domain.rng
+++ b/docs/schemas/domain.rng
@@ -1042,6 +1042,14 @@
               
             
           
+          
+            
+              
+                iothread
+                timer
+              
+            
+          
           
         
       
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index bc4fe29d31..01a5b2ce2c 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -198,6 +198,11 @@ VIR_ENUM_IMPL(virDomainNetBackend, VIR_DOMAIN_NET_BACKEND_TYPE_LAST,
               "qemu",
               "vhost")
 
+VIR_ENUM_IMPL(virDomainNetVirtioTxMode, VIR_DOMAIN_NET_VIRTIO_TX_MODE_LAST,
+              "default",
+              "iothread",
+              "timer")
+
 VIR_ENUM_IMPL(virDomainChrChannelTarget,
               VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_LAST,
               "guestfwd",
@@ -2477,6 +2482,7 @@ virDomainNetDefParseXML(virCapsPtr caps,
     char *port = NULL;
     char *model = NULL;
     char *backend = NULL;
+    char *txmode = NULL;
     char *filter = NULL;
     char *internal = NULL;
     char *devaddr = NULL;
@@ -2565,6 +2571,7 @@ virDomainNetDefParseXML(virCapsPtr caps,
                 model = virXMLPropString(cur, "type");
             } else if (xmlStrEqual (cur->name, BAD_CAST "driver")) {
                 backend = virXMLPropString(cur, "name");
+                txmode = virXMLPropString(cur, "txmode");
             } else if (xmlStrEqual (cur->name, BAD_CAST "filterref")) {
                 filter = virXMLPropString(cur, "filter");
                 VIR_FREE(filterparams);
@@ -2769,6 +2776,18 @@ virDomainNetDefParseXML(virCapsPtr caps,
             }
             def->driver.virtio.name = name;
         }
+        if (txmode != NULL) {
+            int m;
+            if (((m = virDomainNetVirtioTxModeTypeFromString(txmode)) < 0) ||
+                (m == VIR_DOMAIN_NET_VIRTIO_TX_MODE_DEFAULT)) {
+                virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                                     _("Unknown interface  "
+                                       "has been specified"),
+                                     txmode);
+                goto error;
+            }
+            def->driver.virtio.txmode = m;
+        }
     }
 
     if (filter != NULL) {
@@ -2808,6 +2827,7 @@ cleanup:
     VIR_FREE(bridge);
     VIR_FREE(model);
     VIR_FREE(backend);
+    VIR_FREE(txmode);
     VIR_FREE(filter);
     VIR_FREE(type);
     VIR_FREE(internal);
@@ -6813,12 +6833,16 @@ virDomainNetDefFormat(virBufferPtr buf,
         virBufferEscapeString(buf, "      \n",
                               def->model);
         if (STREQ(def->model, "virtio") &&
-            def->driver.virtio.name) {
+            (def->driver.virtio.name || def->driver.virtio.txmode)) {
             virBufferAddLit(buf, "      driver.virtio.name) {
                 virBufferVSprintf(buf, " name='%s'",
                                   virDomainNetBackendTypeToString(def->driver.virtio.name));
             }
+            if (def->driver.virtio.txmode) {
+                virBufferVSprintf(buf, " txmode='%s'",
+                                  virDomainNetVirtioTxModeTypeToString(def->driver.virtio.txmode));
+            }
             virBufferAddLit(buf, "/>\n");
         }
     }
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index e05064fb49..30aecccdb6 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -321,6 +321,15 @@ enum virDomainNetBackendType {
     VIR_DOMAIN_NET_BACKEND_TYPE_LAST,
 };
 
+/* the TX algorithm used for virtio interfaces */
+enum virDomainNetVirtioTxModeType {
+    VIR_DOMAIN_NET_VIRTIO_TX_MODE_DEFAULT, /* default for this version of qemu */
+    VIR_DOMAIN_NET_VIRTIO_TX_MODE_IOTHREAD,
+    VIR_DOMAIN_NET_VIRTIO_TX_MODE_TIMER,
+
+    VIR_DOMAIN_NET_VIRTIO_TX_MODE_LAST,
+};
+
 /* the mode type for macvtap devices */
 enum virDomainNetdevMacvtapType {
     VIR_DOMAIN_NETDEV_MACVTAP_MODE_VEPA,
@@ -341,6 +350,7 @@ struct _virDomainNetDef {
     union {
         struct {
             enum virDomainNetBackendType name; /* which driver backend to use */
+            enum virDomainNetVirtioTxModeType txmode;
         } virtio;
     } driver;
     union {
@@ -1371,6 +1381,7 @@ VIR_ENUM_DECL(virDomainFS)
 VIR_ENUM_DECL(virDomainFSAccessMode)
 VIR_ENUM_DECL(virDomainNet)
 VIR_ENUM_DECL(virDomainNetBackend)
+VIR_ENUM_DECL(virDomainNetVirtioTxMode)
 VIR_ENUM_DECL(virDomainChrDevice)
 VIR_ENUM_DECL(virDomainChrChannelTarget)
 VIR_ENUM_DECL(virDomainChrConsoleTarget)
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index cc5552cc38..5f08a2012f 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -1074,6 +1074,7 @@ qemuCapsExtractDeviceStr(const char *qemu,
                                "-device", "?",
                                "-device", "pci-assign,?",
                                "-device", "virtio-blk-pci,?",
+                               "-device", "virtio-net-pci,?",
                                NULL);
     virCommandAddEnvPassCommon(cmd);
     /* qemu -help goes to stdout, but qemu -device ? goes to stderr.  */
@@ -1115,6 +1116,8 @@ qemuCapsParseDeviceStr(const char *str, unsigned long long *flags)
         if (strstr(str, "pci-assign.bootindex"))
             *flags |= QEMUD_CMD_FLAG_PCI_BOOTINDEX;
     }
+    if (strstr(str, "virtio-net-pci.tx="))
+        *flags |= QEMUD_CMD_FLAG_VIRTIO_TX_ALG;
 
     return 0;
 }
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index a130a4f993..63cbbb3975 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -92,6 +92,7 @@ enum qemuCapsFlags {
     QEMUD_CMD_FLAG_CCID_PASSTHRU = (1LL << 55), /* -device ccid-card-passthru */
     QEMUD_CMD_FLAG_CHARDEV_SPICEVMC = (1LL << 56), /* newer -chardev spicevmc */
     QEMUD_CMD_FLAG_DEVICE_SPICEVMC = (1LL << 57), /* older -device spicevmc*/
+    QEMUD_CMD_FLAG_VIRTIO_TX_ALG = (1LL << 58), /* -device virtio-net-pci,tx=string */
 };
 
 virCapsPtr qemuCapsInit(virCapsPtr old_caps);
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 7a52f4e9ad..b0eddd4e73 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -1606,16 +1606,43 @@ qemuBuildNicDevStr(virDomainNetDefPtr net,
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
     const char *nic;
+    bool usingVirtio = false;
 
     if (!net->model) {
         nic = "rtl8139";
     } else if (STREQ(net->model, "virtio")) {
         nic = "virtio-net-pci";
+        usingVirtio = true;
     } else {
         nic = net->model;
     }
 
     virBufferAdd(&buf, nic, strlen(nic));
+    if (usingVirtio && net->driver.virtio.txmode) {
+        if (qemuCmdFlags & QEMUD_CMD_FLAG_VIRTIO_TX_ALG) {
+            virBufferAddLit(&buf, ",tx=");
+            switch (net->driver.virtio.txmode) {
+                case VIR_DOMAIN_NET_VIRTIO_TX_MODE_IOTHREAD:
+                    virBufferAddLit(&buf, "bh");
+                    break;
+
+                case VIR_DOMAIN_NET_VIRTIO_TX_MODE_TIMER:
+                    virBufferAddLit(&buf, "timer");
+                    break;
+                default:
+                    /* this should never happen, if it does, we need
+                     * to add another case to this switch.
+                     */
+                    qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                                    _("unrecognized virtio-net-pci 'tx' option"));
+                    goto error;
+            }
+        } else {
+            qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                            _("virtio-net-pci 'tx' option not supported in this QEMU binary"));
+            goto error;
+        }
+    }
     if (vlan == -1)
         virBufferVSprintf(&buf, ",netdev=host%s", net->info.alias);
     else
diff --git a/tests/qemuhelpdata/qemu-kvm-0.12.1.2-rhel61-device b/tests/qemuhelpdata/qemu-kvm-0.12.1.2-rhel61-device
index 8a0e528315..8ac9630b40 100644
--- a/tests/qemuhelpdata/qemu-kvm-0.12.1.2-rhel61-device
+++ b/tests/qemuhelpdata/qemu-kvm-0.12.1.2-rhel61-device
@@ -72,3 +72,28 @@ virtio-blk-pci.ioeventfd=on/off
 virtio-blk-pci.vectors=uint32
 virtio-blk-pci.indirect_desc=on/off
 virtio-blk-pci.scsi=on/off
+virtio-net-pci.vectors=uint32
+virtio-net-pci.indirect_desc=on/off
+virtio-net-pci.csum=on/off
+virtio-net-pci.guest_csum=on/off
+virtio-net-pci.gso=on/off
+virtio-net-pci.guest_tso4=on/off
+virtio-net-pci.guest_tso6=on/off
+virtio-net-pci.guest_ecn=on/off
+virtio-net-pci.guest_ufo=on/off
+virtio-net-pci.host_tso4=on/off
+virtio-net-pci.host_tso6=on/off
+virtio-net-pci.host_ecn=on/off
+virtio-net-pci.host_ufo=on/off
+virtio-net-pci.mrg_rxbuf=on/off
+virtio-net-pci.status=on/off
+virtio-net-pci.ctrl_vq=on/off
+virtio-net-pci.ctrl_rx=on/off
+virtio-net-pci.ctrl_vlan=on/off
+virtio-net-pci.ctrl_rx_extra=on/off
+virtio-net-pci.mac=macaddr
+virtio-net-pci.vlan=vlan
+virtio-net-pci.netdev=netdev
+virtio-net-pci.x-txtimer=uint32
+virtio-net-pci.x-txburst=int32
+virtio-net-pci.tx=string
diff --git a/tests/qemuhelpdata/qemu-kvm-0.13.0-device b/tests/qemuhelpdata/qemu-kvm-0.13.0-device
index b121257874..4888d187f7 100644
--- a/tests/qemuhelpdata/qemu-kvm-0.13.0-device
+++ b/tests/qemuhelpdata/qemu-kvm-0.13.0-device
@@ -68,3 +68,25 @@ name "pci-assign", bus PCI, desc "pass through host pci devices to the guest"
 pci-assign.host=pci-hostaddr
 pci-assign.iommu=uint32
 pci-assign.configfd=string
+virtio-net-pci.vectors=uint32
+virtio-net-pci.indirect_desc=on/off
+virtio-net-pci.csum=on/off
+virtio-net-pci.guest_csum=on/off
+virtio-net-pci.gso=on/off
+virtio-net-pci.guest_tso4=on/off
+virtio-net-pci.guest_tso6=on/off
+virtio-net-pci.guest_ecn=on/off
+virtio-net-pci.guest_ufo=on/off
+virtio-net-pci.host_tso4=on/off
+virtio-net-pci.host_tso6=on/off
+virtio-net-pci.host_ecn=on/off
+virtio-net-pci.host_ufo=on/off
+virtio-net-pci.mrg_rxbuf=on/off
+virtio-net-pci.status=on/off
+virtio-net-pci.ctrl_vq=on/off
+virtio-net-pci.ctrl_rx=on/off
+virtio-net-pci.ctrl_vlan=on/off
+virtio-net-pci.ctrl_rx_extra=on/off
+virtio-net-pci.mac=macaddr
+virtio-net-pci.vlan=vlan
+virtio-net-pci.netdev=netdev
diff --git a/tests/qemuhelptest.c b/tests/qemuhelptest.c
index 3a04b610f5..11890ab16d 100644
--- a/tests/qemuhelptest.c
+++ b/tests/qemuhelptest.c
@@ -480,7 +480,8 @@ mymain(int argc, char **argv)
             QEMUD_CMD_FLAG_HDA_DUPLEX |
             QEMUD_CMD_FLAG_DRIVE_AIO |
             QEMUD_CMD_FLAG_CCID_PASSTHRU |
-            QEMUD_CMD_FLAG_CHARDEV_SPICEVMC,
+            QEMUD_CMD_FLAG_CHARDEV_SPICEVMC |
+            QEMUD_CMD_FLAG_VIRTIO_TX_ALG,
             12001, 1,  0);
 
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.args b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.args
index 92bd889b12..843c3e9933 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.args
@@ -1,6 +1,6 @@
 LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M \
 pc -m 214 -smp 1 -nographic -nodefconfig -nodefaults -monitor \
 unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -hda \
-/dev/HostVG/QEMUGuest1 -device virtio-net-pci,vlan=0,id=net0,\
+/dev/HostVG/QEMUGuest1 -device virtio-net-pci,tx=bh,vlan=0,id=net0,\
 mac=00:11:22:33:44:55,bus=pci.0,addr=0x2 -net user,vlan=0,name=hostnet0 -usb \
 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml
index 572f3cc757..4e7abcd554 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.xml
@@ -17,10 +17,13 @@
     
       
       
+      

     
+    
     
       
       
+      
     
     
   
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 96260c0d81..4817d511ce 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -365,7 +365,7 @@ mymain(int argc, char **argv)
     DO_TEST("net-user", 0, false);
     DO_TEST("net-virtio", 0, false);
     DO_TEST("net-virtio-device", QEMUD_CMD_FLAG_DEVICE |
-            QEMUD_CMD_FLAG_NODEFCONFIG, false);
+            QEMUD_CMD_FLAG_NODEFCONFIG | QEMUD_CMD_FLAG_VIRTIO_TX_ALG, false);
     DO_TEST("net-virtio-netdev", QEMUD_CMD_FLAG_DEVICE |
             QEMUD_CMD_FLAG_NETDEV | QEMUD_CMD_FLAG_NODEFCONFIG, false);
     DO_TEST("net-eth", 0, false);
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index 15d94b764f..67e721b8b2 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -159,6 +159,7 @@ mymain(int argc, char **argv)
     DO_TEST("misc-no-reboot");
     DO_TEST("net-user");
     DO_TEST("net-virtio");
+    DO_TEST("net-virtio-device");
     DO_TEST("net-eth");
     DO_TEST("net-eth-ifname");
     DO_TEST("sound");