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https://gitlab.com/libvirt/libvirt.git
synced 2024-08-28 11:31:16 +00:00
Enable tuning of qemu network tap device "sndbuf" size
This is in response to a request in: https://bugzilla.redhat.com/show_bug.cgi?id=665293 In short, under heavy load, it's possible for qemu's networking to lock up due to the tap device's default 1MB sndbuf being inadequate. adding "sndbuf=0" to the qemu commandline -netdevice option will alleviate this problem (sndbuf=0 actually sets it to 0xffffffff). Because we must be able to explicitly specify "0" as a value, the standard practice of "0 means not specified" won't work here. Instead, virDomainNetDef also has a sndbuf_specified, which defaults to 0, but is set to 1 if some value was given. The sndbuf value is put inside a <tune> element of each <interface> in the domain. The intent is that further tunable settings will also be placed inside this element. <interface type='network'> ... <tune> <sndbuf>0</sndbuf> ... </tune> </interface>
This commit is contained in:
parent
175077fd70
commit
fe053dbea7
@ -1025,6 +1025,16 @@
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<ref name="filterref-node-attributes"/>
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<ref name="filterref-node-attributes"/>
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</element>
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</element>
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</optional>
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</optional>
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<optional>
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<element name="tune">
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<optional>
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<!-- size of send buffer for network tap devices -->
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<element name="sndbuf">
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<ref name="unsignedInt"/>
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</element>
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</optional>
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</element>
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</optional>
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</interleave>
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</interleave>
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</define>
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</define>
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<define name="virtualPortProfile">
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<define name="virtualPortProfile">
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@ -2296,6 +2296,7 @@ err_exit:
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static virDomainNetDefPtr
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static virDomainNetDefPtr
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virDomainNetDefParseXML(virCapsPtr caps,
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virDomainNetDefParseXML(virCapsPtr caps,
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xmlNodePtr node,
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xmlNodePtr node,
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xmlXPathContextPtr ctxt,
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int flags ATTRIBUTE_UNUSED) {
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int flags ATTRIBUTE_UNUSED) {
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virDomainNetDefPtr def;
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virDomainNetDefPtr def;
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xmlNodePtr cur;
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xmlNodePtr cur;
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@ -2317,12 +2318,16 @@ virDomainNetDefParseXML(virCapsPtr caps,
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virNWFilterHashTablePtr filterparams = NULL;
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virNWFilterHashTablePtr filterparams = NULL;
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virVirtualPortProfileParams virtPort;
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virVirtualPortProfileParams virtPort;
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bool virtPortParsed = false;
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bool virtPortParsed = false;
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xmlNodePtr oldnode = ctxt->node;
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int ret;
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if (VIR_ALLOC(def) < 0) {
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if (VIR_ALLOC(def) < 0) {
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virReportOOMError();
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virReportOOMError();
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return NULL;
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return NULL;
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}
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}
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ctxt->node = node;
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type = virXMLPropString(node, "type");
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type = virXMLPropString(node, "type");
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if (type != NULL) {
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if (type != NULL) {
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if ((int)(def->type = virDomainNetTypeFromString(type)) < 0) {
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if ((int)(def->type = virDomainNetTypeFromString(type)) < 0) {
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@ -2610,7 +2615,17 @@ virDomainNetDefParseXML(virCapsPtr caps,
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}
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}
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}
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}
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ret = virXPathULong("string(./tune/sndbuf)", ctxt, &def->tune.sndbuf);
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if (ret >= 0) {
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def->tune.sndbuf_specified = true;
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} else if (ret == -2) {
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virDomainReportError(VIR_ERR_XML_ERROR, "%s",
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_("sndbuf must be a positive integer"));
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goto error;
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}
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cleanup:
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cleanup:
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ctxt->node = oldnode;
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VIR_FREE(macaddr);
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VIR_FREE(macaddr);
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VIR_FREE(network);
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VIR_FREE(network);
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VIR_FREE(address);
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VIR_FREE(address);
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@ -4348,6 +4363,7 @@ virDomainDeviceDefPtr virDomainDeviceDefParse(virCapsPtr caps,
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{
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{
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xmlDocPtr xml;
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xmlDocPtr xml;
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xmlNodePtr node;
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xmlNodePtr node;
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xmlXPathContextPtr ctxt = NULL;
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virDomainDeviceDefPtr dev = NULL;
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virDomainDeviceDefPtr dev = NULL;
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if (!(xml = xmlReadDoc(BAD_CAST xmlStr, "device.xml", NULL,
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if (!(xml = xmlReadDoc(BAD_CAST xmlStr, "device.xml", NULL,
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@ -4364,6 +4380,13 @@ virDomainDeviceDefPtr virDomainDeviceDefParse(virCapsPtr caps,
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goto error;
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goto error;
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}
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}
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ctxt = xmlXPathNewContext(xml);
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if (ctxt == NULL) {
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virReportOOMError();
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goto error;
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}
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ctxt->node = node;
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if (VIR_ALLOC(dev) < 0) {
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if (VIR_ALLOC(dev) < 0) {
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virReportOOMError();
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virReportOOMError();
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goto error;
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goto error;
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@ -4379,7 +4402,7 @@ virDomainDeviceDefPtr virDomainDeviceDefParse(virCapsPtr caps,
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goto error;
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goto error;
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} else if (xmlStrEqual(node->name, BAD_CAST "interface")) {
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} else if (xmlStrEqual(node->name, BAD_CAST "interface")) {
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dev->type = VIR_DOMAIN_DEVICE_NET;
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dev->type = VIR_DOMAIN_DEVICE_NET;
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if (!(dev->data.net = virDomainNetDefParseXML(caps, node, flags)))
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if (!(dev->data.net = virDomainNetDefParseXML(caps, node, ctxt, flags)))
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goto error;
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goto error;
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} else if (xmlStrEqual(node->name, BAD_CAST "input")) {
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} else if (xmlStrEqual(node->name, BAD_CAST "input")) {
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dev->type = VIR_DOMAIN_DEVICE_INPUT;
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dev->type = VIR_DOMAIN_DEVICE_INPUT;
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@ -4417,11 +4440,12 @@ virDomainDeviceDefPtr virDomainDeviceDefParse(virCapsPtr caps,
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}
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}
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xmlFreeDoc(xml);
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xmlFreeDoc(xml);
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xmlXPathFreeContext(ctxt);
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return dev;
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return dev;
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error:
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error:
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xmlFreeDoc(xml);
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xmlFreeDoc(xml);
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xmlXPathFreeContext(ctxt);
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VIR_FREE(dev);
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VIR_FREE(dev);
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return NULL;
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return NULL;
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}
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}
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@ -5092,6 +5116,7 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
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for (i = 0 ; i < n ; i++) {
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for (i = 0 ; i < n ; i++) {
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virDomainNetDefPtr net = virDomainNetDefParseXML(caps,
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virDomainNetDefPtr net = virDomainNetDefParseXML(caps,
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nodes[i],
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nodes[i],
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ctxt,
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flags);
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flags);
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if (!net)
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if (!net)
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goto error;
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goto error;
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@ -6360,6 +6385,12 @@ virDomainNetDefFormat(virBufferPtr buf,
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VIR_FREE(attrs);
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VIR_FREE(attrs);
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}
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}
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if (def->tune.sndbuf_specified) {
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virBufferAddLit(buf, " <tune>\n");
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virBufferVSprintf(buf, " <sndbuf>%lu</sndbuf>\n", def->tune.sndbuf);
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virBufferAddLit(buf, " </tune>\n");
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}
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if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
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if (virDomainDeviceInfoFormat(buf, &def->info, flags) < 0)
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return -1;
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return -1;
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@ -346,6 +346,10 @@ struct _virDomainNetDef {
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virVirtualPortProfileParams virtPortProfile;
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virVirtualPortProfileParams virtPortProfile;
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} direct;
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} direct;
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} data;
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} data;
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struct {
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bool sndbuf_specified;
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unsigned long sndbuf;
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} tune;
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char *ifname;
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char *ifname;
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virDomainDeviceInfo info;
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virDomainDeviceInfo info;
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char *filter;
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char *filter;
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@ -1584,6 +1584,7 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
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const char *tapfd,
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const char *tapfd,
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const char *vhostfd)
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const char *vhostfd)
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{
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{
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bool is_tap = false;
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virBuffer buf = VIR_BUFFER_INITIALIZER;
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virBuffer buf = VIR_BUFFER_INITIALIZER;
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switch (net->type) {
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switch (net->type) {
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@ -1593,6 +1594,7 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
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virBufferAddLit(&buf, "tap");
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virBufferAddLit(&buf, "tap");
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virBufferVSprintf(&buf, "%cfd=%s", type_sep, tapfd);
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virBufferVSprintf(&buf, "%cfd=%s", type_sep, tapfd);
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type_sep = ',';
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type_sep = ',';
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is_tap = true;
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break;
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break;
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case VIR_DOMAIN_NET_TYPE_ETHERNET:
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case VIR_DOMAIN_NET_TYPE_ETHERNET:
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@ -1606,6 +1608,7 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
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net->data.ethernet.script);
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net->data.ethernet.script);
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type_sep = ',';
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type_sep = ',';
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}
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}
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is_tap = true;
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break;
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break;
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case VIR_DOMAIN_NET_TYPE_CLIENT:
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case VIR_DOMAIN_NET_TYPE_CLIENT:
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@ -1659,8 +1662,11 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
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type_sep, net->info.alias);
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type_sep, net->info.alias);
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}
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}
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if (vhostfd && *vhostfd) {
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if (is_tap) {
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virBufferVSprintf(&buf, ",vhost=on,vhostfd=%s", vhostfd);
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if (vhostfd && *vhostfd)
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virBufferVSprintf(&buf, ",vhost=on,vhostfd=%s", vhostfd);
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if (net->tune.sndbuf_specified)
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virBufferVSprintf(&buf, ",sndbuf=%lu", net->tune.sndbuf);
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}
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}
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if (virBufferError(&buf)) {
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if (virBufferError(&buf)) {
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@ -4669,6 +4675,15 @@ qemuParseCommandLineNet(virCapsPtr caps,
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} else if (STREQ(keywords[i], "off")) {
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} else if (STREQ(keywords[i], "off")) {
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def->backend = VIR_DOMAIN_NET_BACKEND_TYPE_QEMU;
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def->backend = VIR_DOMAIN_NET_BACKEND_TYPE_QEMU;
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}
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}
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} else if (STREQ(keywords[i], "sndbuf") && values[i]) {
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if (virStrToLong_ul(values[i], NULL, 10, &def->tune.sndbuf) < 0) {
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qemuReportError(VIR_ERR_INTERNAL_ERROR,
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_("cannot parse sndbuf size in '%s'"), val);
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virDomainNetDefFree(def);
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def = NULL;
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goto cleanup;
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}
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def->tune.sndbuf_specified = true;
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}
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}
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}
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}
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