Re: [PATCH v3] qemu: passt: add support for custom command line arguments

This adds support for custom command line arguments for the passt backend, similar to qemu:commandline. The feature allows passing additional arguments to the passt process for development and testing purposes. The implementation: - Adds a passt XML namespace for custom arguments - Properly taints the domain when custom args are used - Includes comprehensive test coverage - Adds documentation for the new feature Usage example: <interface type='user'> <backend type='passt' xmlns:passt='http://libvirt.org/schemas/domain/passt/1.0'> <passt:commandline> <passt:arg value='--debug'/> <passt:arg value='--verbose'/> </passt:commandline> </backend> </interface> Signed-off-by: Enrique Llorente <ellorent(a)redhat.com&gt;

--- v3: - Fix all test problems - Refactor domain_conf.c to use libvirt xml constructs to have proper indent - Rework documentation and make it more concise - Add domainpassttest.c to check that arguments are passed to passt docs/formatdomain.rst | 38 ++++ src/conf/domain_conf.c | 61 ++++++- src/conf/domain_conf.h | 6 + src/conf/schemas/domaincommon.rng | 15 ++ src/qemu/qemu_passt.c | 9 + tests/meson.build | 1 + tests/qemupassttest.c | 162 ++++++++++++++++++ ...-user-passt-custom-args.x86_64-latest.args | 35 ++++ ...t-user-passt-custom-args.x86_64-latest.xml | 67 ++++++++ .../net-user-passt-custom-args.xml | 64 +++++++ tests/qemuxmlconftest.c | 1 + 11 files changed, 458 insertions(+), 1 deletion(-) create mode 100644 tests/qemupassttest.c create mode 100644 tests/qemuxmlconfdata/net-user-passt-custom-args.x86_64-latest.args create mode 100644 tests/qemuxmlconfdata/net-user-passt-custom-args.x86_64-latest.xml create mode 100644 tests/qemuxmlconfdata/net-user-passt-custom-args.xml diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 9a2f065590..4c01a07135 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -5464,6 +5464,44 @@ ports **with the exception of some subset**. </devices> ... +Custom passt commandline arguments +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. warning::

+ + **This is an unsupported feature for development and testing only.** + Using it will taint the domain. Users are strongly advised to use the + proper libvirt XML elements for configuring passt instead. + + +:since:`Since 11.7.0` For development and testing purposes, it is +sometimes useful to be able to pass additional command-line arguments +directly to the passt process. This can be accomplished using a +special passt namespace in the domain XML that is similar to the qemu +commandline namespace: + +:: + + ... + <devices> + ... + <interface type='user'> + <backend type='passt'> + <passt:commandline xmlns:passt='http://libvirt.org/schemas/domain/passt/1.0'> + <passt:arg value='--debug'/> + <passt:arg value='--verbose'/> + </passt:commandline> + </backend> + </interface> + </devices> + ... + +Any arguments provided using this method will be appended to the passt +command line, and will therefore override any default options set by +libvirt in the case of conflicts. **This can lead to unexpected behavior +and libvirt cannot guarantee functionality when its default configuration +is overridden.**

+ Generic ethernet connection ^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 1e24e41a48..9721763622 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -2918,6 +2918,10 @@ virDomainNetDefFree(virDomainNetDef *def) g_free(def->backend.tap); g_free(def->backend.vhost); g_free(def->backend.logFile); + if (def->backend.passtCommandline) { + g_strfreev(def->backend.passtCommandline->args); + g_free(def->backend.passtCommandline); + } virDomainNetTeamingInfoFree(def->teaming); g_free(def->virtPortProfile); g_free(def->script); @@ -9772,6 +9776,7 @@ virDomainNetBackendParseXML(xmlNodePtr node, { g_autofree char *tap = virXMLPropString(node, "tap"); g_autofree char *vhost = virXMLPropString(node, "vhost"); + xmlNodePtr cur; /* In the case of NET_TYPE_USER, backend type can be unspecified * (i.e. VIR_DOMAIN_NET_BACKEND_DEFAULT) and that means 'use @@ -9808,6 +9813,38 @@ virDomainNetBackendParseXML(xmlNodePtr node, def->backend.vhost = virFileSanitizePath(vhost); } + /* Parse passt namespace commandline */ + cur = node->children; + while (cur != NULL) { + if (cur->type == XML_ELEMENT_NODE) { + if (cur->ns && + STREQ((const char *)cur->ns->href, "http://libvirt.org/schemas/domain/passt/1.0") && + STREQ((const char *)cur->name, "commandline")) { + xmlNodePtr arg_node = cur->children; + g_autoptr(GPtrArray) args = g_ptr_array_new(); + + while (arg_node != NULL) { + if (arg_node->type == XML_ELEMENT_NODE && + arg_node->ns && + STREQ((const char *)arg_node->ns->href, "http://libvirt.org/schemas/domain/passt/1.0") && + STREQ((const char *)arg_node->name, "arg")) { + g_autofree char *value = virXMLPropString(arg_node, "value"); + if (value) + g_ptr_array_add(args, g_strdup(value)); + } + arg_node = arg_node->next; + } + + if (args->len > 0) { + def->backend.passtCommandline = g_new0(virDomainNetBackendPasstCommandline, 1); + g_ptr_array_add(args, NULL); /* NULL-terminate */ + def->backend.passtCommandline->args = (char **)g_ptr_array_steal(args, NULL); + } + } + } + cur = cur->next; + } + return 0; } @@ -20802,6 +20839,7 @@ virDomainNetBackendIsEqual(virDomainNetBackend *src, STRNEQ_NULLABLE(src->logFile, dst->logFile)) { return false; } + return true;

}

diff --git a/tests/qemupassttest.c b/tests/qemupassttest.c new file mode 100644 index 0000000000..84f4c1510a --- /dev/null +++ b/tests/qemupassttest.c @@ -0,0 +1,162 @@ +/* + * Copyright (C) 2024 Red Hat, Inc.

+ * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see + * <http://www.gnu.org/licenses/>;. + */ + +#include <config.h> + +#include "testutils.h" +#include "conf/domain_conf.h" +#include "viralloc.h" +#include "virstring.h" +#include "virlog.h" + +#define VIR_FROM_THIS VIR_FROM_QEMU + +VIR_LOG_INIT("tests.qemupassttest"); + +struct testPasstData { + const char *name; + const char *xmlfile; + const char * const *expectedArgs; + size_t nExpectedArgs; + bool expectCustomArgs; +}; + +static virDomainDef * +testParseDomainXML(const char *xmlfile) +{ + g_autofree char *xmlpath = NULL; + g_autofree char *xmldata = NULL; + virDomainDef *def = NULL; + g_autoptr(virDomainXMLOption) xmlopt = NULL; + + xmlpath = g_strdup_printf("%s/qemuxmlconfdata/%s", abs_srcdir, xmlfile); + + if (virTestLoadFile(xmlpath, &xmldata) < 0) + return NULL; + + if (!(xmlopt = virDomainXMLOptionNew(NULL, NULL, NULL, NULL, NULL, NULL))) + return NULL; + + def = virDomainDefParseString(xmldata, xmlopt, NULL, + VIR_DOMAIN_DEF_PARSE_INACTIVE);

+ + return def; +} + +static int +testPasstParseCustomArgs(const void *opaque) +{ + const struct testPasstData *data = opaque; + g_autoptr(virDomainDef) def = NULL; + virDomainNetDef *net = NULL; + size_t i; + + if (!(def = testParseDomainXML(data->xmlfile))) { + VIR_TEST_DEBUG("Failed to parse domain XML"); + return -1; + } + + /* Find the interface with passt backend */ + for (i = 0; i < def->nnets; i++) { + if (def->nets[i]->backend.type == VIR_DOMAIN_NET_BACKEND_PASST) { + net = def->nets[i]; + break; + } + } + + if (!net) { + VIR_TEST_DEBUG("No passt interface found in domain XML"); + return -1; + } + + /* Check if we have custom arguments */ + if (data->expectCustomArgs) { + char **args; + + if (!net->backend.passtCommandline || !net->backend.passtCommandline->args) { + VIR_TEST_DEBUG("Expected custom args but none found"); + return -1; + } + + args = net->backend.passtCommandline->args; + + if (g_strv_length(args) != data->nExpectedArgs) { + VIR_TEST_DEBUG("Expected %zu arguments but found %u", + data->nExpectedArgs, g_strv_length(args)); + return -1; + } + + /* Verify all expected arguments are present */ + for (i = 0; i < data->nExpectedArgs; i++) { + if (!g_strv_contains((const char * const *)args, data->expectedArgs[i])) { + VIR_TEST_DEBUG("Missing expected argument: %s", data->expectedArgs[i]); + return -1;