| Message ID | 20220620101828.518865-4-lvivier@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | qapi: net: add unix socket type support to netdev backend | expand |
Laurent Vivier <lvivier@redhat.com> writes: > As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field > of Netdev structure can collides with "type" field of SocketAddress), > we introduce a way to bypass qemu_opts_parse_noisily() and use directly > visit_type_Netdev() to parse the backend parameters. > > More details from Markus: > > qemu_init() passes the argument of -netdev, -nic, and -net to > net_client_parse(). > > net_client_parse() parses with qemu_opts_parse_noisily(), passing > QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and > qemu_net_opts for -net. Their desc[] are all empty, which means any > keys are accepted. The result of the parse (a QemuOpts) is stored in > the QemuOptsList. > > Note that QemuOpts is flat by design. In some places, we layer non-flat > on top using dotted keys convention, but not here. > > net_init_clients() iterates over the stored QemuOpts, and passes them to > net_init_netdev(), net_param_nic(), or net_init_client(), respectively. > > These functions pass the QemuOpts to net_client_init(). They also do > other things with the QemuOpts, which we can ignore here. > > net_client_init() uses the opts visitor to convert the (flat) QemOpts to > a (non-flat) QAPI object Netdev. Netdev is also the argument of QMP > command netdev_add. > > The opts visitor was an early attempt to support QAPI in > (QemuOpts-based) CLI. It restricts QAPI types to a certain shape; see > commit eb7ee2cbeb "qapi: introduce OptsVisitor". > > A more modern way to support QAPI is qobject_input_visitor_new_str(). > It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and > it also supports JSON syntax. The former isn't quite as expressive as > JSON, but it's a lot closer than QemuOpts + opts visitor. > > This commit paves the way to use of the modern way instead. > > Signed-off-by: Laurent Vivier <lvivier@redhat.com> > --- > include/net/net.h | 1 + > net/net.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++ > softmmu/vl.c | 3 ++- > 3 files changed, 63 insertions(+), 1 deletion(-) > > diff --git a/include/net/net.h b/include/net/net.h > index c53c64ac18c4..4ae8ed480f73 100644 > --- a/include/net/net.h > +++ b/include/net/net.h > @@ -214,6 +214,7 @@ extern NICInfo nd_table[MAX_NICS]; > extern const char *host_net_devices[]; > > /* from net.c */ > +int netdev_parse_modern(const char *optarg); > int net_client_parse(QemuOptsList *opts_list, const char *str); > void show_netdevs(void); > void net_init_clients(void); > diff --git a/net/net.c b/net/net.c > index 15958f881776..c337d3d753fe 100644 > --- a/net/net.c > +++ b/net/net.c > @@ -54,6 +54,7 @@ > #include "net/colo-compare.h" > #include "net/filter.h" > #include "qapi/string-output-visitor.h" > +#include "qapi/qobject-input-visitor.h" > > /* Net bridge is currently not supported for W32. */ > #if !defined(_WIN32) > @@ -63,6 +64,16 @@ > static VMChangeStateEntry *net_change_state_entry; > static QTAILQ_HEAD(, NetClientState) net_clients; > > +typedef struct NetdevQueueEntry { > + Netdev *nd; > + Location loc; > + QSIMPLEQ_ENTRY(NetdevQueueEntry) entry; > +} NetdevQueueEntry; > + > +typedef QSIMPLEQ_HEAD(, NetdevQueueEntry) NetdevQueue; > + > +static NetdevQueue nd_queue = QSIMPLEQ_HEAD_INITIALIZER(nd_queue); > + > /***********************************************************/ > /* network device redirectors */ > > @@ -1562,6 +1573,20 @@ out: > return ret; > } > > +static void netdev_init_modern(void) > +{ > + while (!QSIMPLEQ_EMPTY(&nd_queue)) { > + NetdevQueueEntry *nd = QSIMPLEQ_FIRST(&nd_queue); > + > + QSIMPLEQ_REMOVE_HEAD(&nd_queue, entry); > + loc_push_restore(&nd->loc); > + net_client_init1(nd->nd, true, &error_fatal); > + loc_pop(&nd->loc); > + qapi_free_Netdev(nd->nd); > + g_free(nd); > + } > +} > + > void net_init_clients(void) > { > net_change_state_entry = > @@ -1569,6 +1594,8 @@ void net_init_clients(void) > > QTAILQ_INIT(&net_clients); > > + netdev_init_modern(); > + > qemu_opts_foreach(qemu_find_opts("netdev"), net_init_netdev, NULL, > &error_fatal); > > @@ -1579,6 +1606,39 @@ void net_init_clients(void) > &error_fatal); > } > > +/* > + * netdev_is_modern() returns true when the backend needs to bypass > + * qemu_opts_parse_noisily() > + */ > +static bool netdev_is_modern(const char *optarg) > +{ > + return false; > +} > + > +/* > + * netdev_parse_modern() uses modern, more expressive syntax than > + * net_client_parse(), supports only the netdev option. > + */ > +int netdev_parse_modern(const char *optarg) > +{ > + Visitor *v; > + NetdevQueueEntry *nd; > + > + if (!netdev_is_modern(optarg)) { > + return -1; > + } > + > + v = qobject_input_visitor_new_str(optarg, "type", &error_fatal); > + nd = g_new(NetdevQueueEntry, 1); > + visit_type_Netdev(v, NULL, &nd->nd, &error_fatal); > + visit_free(v); > + loc_save(&nd->loc); > + > + QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry); > + > + return 0; > +} > + > int net_client_parse(QemuOptsList *opts_list, const char *optarg) > { > if (!qemu_opts_parse_noisily(opts_list, optarg, true)) { > diff --git a/softmmu/vl.c b/softmmu/vl.c > index 8eed0f31c073..838f5b48c447 100644 > --- a/softmmu/vl.c > +++ b/softmmu/vl.c > @@ -2839,7 +2839,8 @@ void qemu_init(int argc, char **argv, char **envp) > break; > case QEMU_OPTION_netdev: > default_net = 0; > - if (net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { > + if (netdev_parse_modern(optarg) == -1 && > + net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { > exit(1); > } > break; To make this work, netdev_parse_modern() must * either succeeed, or * fail without reporting an error, or * report an error and exit() Recommend to spell that out in its function comment. Alternatively: if (netdev_is_modern(optarg)) { netdev_parse_modern(optarg); } else { if (net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { exit(1); } } netdev_is_modern() needs external linkage, and netdev_parse_modern() loses its return value. Note that all callers net_client_parse() handle failure exactly the same way. If we let net_client_parse() exit(), then this becomes if (netdev_is_modern(optarg)) { netdev_parse_modern(optarg); } else { net_client_parse(qemu_find_opts("netdev"), optarg); } I like this one best. What do you think? Regardless of which alternative we pick: error reporting depends on netdev_is_modern(). To be discussed in my review of the next patch.
On 20/06/2022 14:43, Markus Armbruster wrote: > Laurent Vivier <lvivier@redhat.com> writes: > >> As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field >> of Netdev structure can collides with "type" field of SocketAddress), >> we introduce a way to bypass qemu_opts_parse_noisily() and use directly >> visit_type_Netdev() to parse the backend parameters. >> >> More details from Markus: >> >> qemu_init() passes the argument of -netdev, -nic, and -net to >> net_client_parse(). >> >> net_client_parse() parses with qemu_opts_parse_noisily(), passing >> QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and >> qemu_net_opts for -net. Their desc[] are all empty, which means any >> keys are accepted. The result of the parse (a QemuOpts) is stored in >> the QemuOptsList. >> >> Note that QemuOpts is flat by design. In some places, we layer non-flat >> on top using dotted keys convention, but not here. >> >> net_init_clients() iterates over the stored QemuOpts, and passes them to >> net_init_netdev(), net_param_nic(), or net_init_client(), respectively. >> >> These functions pass the QemuOpts to net_client_init(). They also do >> other things with the QemuOpts, which we can ignore here. >> >> net_client_init() uses the opts visitor to convert the (flat) QemOpts to >> a (non-flat) QAPI object Netdev. Netdev is also the argument of QMP >> command netdev_add. >> >> The opts visitor was an early attempt to support QAPI in >> (QemuOpts-based) CLI. It restricts QAPI types to a certain shape; see >> commit eb7ee2cbeb "qapi: introduce OptsVisitor". >> >> A more modern way to support QAPI is qobject_input_visitor_new_str(). >> It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and >> it also supports JSON syntax. The former isn't quite as expressive as >> JSON, but it's a lot closer than QemuOpts + opts visitor. >> >> This commit paves the way to use of the modern way instead. >> >> Signed-off-by: Laurent Vivier <lvivier@redhat.com> >> --- >> include/net/net.h | 1 + >> net/net.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++ >> softmmu/vl.c | 3 ++- >> 3 files changed, 63 insertions(+), 1 deletion(-) >> >> diff --git a/include/net/net.h b/include/net/net.h >> index c53c64ac18c4..4ae8ed480f73 100644 >> --- a/include/net/net.h >> +++ b/include/net/net.h >> @@ -214,6 +214,7 @@ extern NICInfo nd_table[MAX_NICS]; >> extern const char *host_net_devices[]; >> >> /* from net.c */ >> +int netdev_parse_modern(const char *optarg); >> int net_client_parse(QemuOptsList *opts_list, const char *str); >> void show_netdevs(void); >> void net_init_clients(void); >> diff --git a/net/net.c b/net/net.c >> index 15958f881776..c337d3d753fe 100644 >> --- a/net/net.c >> +++ b/net/net.c >> @@ -54,6 +54,7 @@ >> #include "net/colo-compare.h" >> #include "net/filter.h" >> #include "qapi/string-output-visitor.h" >> +#include "qapi/qobject-input-visitor.h" >> >> /* Net bridge is currently not supported for W32. */ >> #if !defined(_WIN32) >> @@ -63,6 +64,16 @@ >> static VMChangeStateEntry *net_change_state_entry; >> static QTAILQ_HEAD(, NetClientState) net_clients; >> >> +typedef struct NetdevQueueEntry { >> + Netdev *nd; >> + Location loc; >> + QSIMPLEQ_ENTRY(NetdevQueueEntry) entry; >> +} NetdevQueueEntry; >> + >> +typedef QSIMPLEQ_HEAD(, NetdevQueueEntry) NetdevQueue; >> + >> +static NetdevQueue nd_queue = QSIMPLEQ_HEAD_INITIALIZER(nd_queue); >> + >> /***********************************************************/ >> /* network device redirectors */ >> >> @@ -1562,6 +1573,20 @@ out: >> return ret; >> } >> >> +static void netdev_init_modern(void) >> +{ >> + while (!QSIMPLEQ_EMPTY(&nd_queue)) { >> + NetdevQueueEntry *nd = QSIMPLEQ_FIRST(&nd_queue); >> + >> + QSIMPLEQ_REMOVE_HEAD(&nd_queue, entry); >> + loc_push_restore(&nd->loc); >> + net_client_init1(nd->nd, true, &error_fatal); >> + loc_pop(&nd->loc); >> + qapi_free_Netdev(nd->nd); >> + g_free(nd); >> + } >> +} >> + >> void net_init_clients(void) >> { >> net_change_state_entry = >> @@ -1569,6 +1594,8 @@ void net_init_clients(void) >> >> QTAILQ_INIT(&net_clients); >> >> + netdev_init_modern(); >> + >> qemu_opts_foreach(qemu_find_opts("netdev"), net_init_netdev, NULL, >> &error_fatal); >> >> @@ -1579,6 +1606,39 @@ void net_init_clients(void) >> &error_fatal); >> } >> >> +/* >> + * netdev_is_modern() returns true when the backend needs to bypass >> + * qemu_opts_parse_noisily() >> + */ >> +static bool netdev_is_modern(const char *optarg) >> +{ >> + return false; >> +} >> + >> +/* >> + * netdev_parse_modern() uses modern, more expressive syntax than >> + * net_client_parse(), supports only the netdev option. >> + */ >> +int netdev_parse_modern(const char *optarg) >> +{ >> + Visitor *v; >> + NetdevQueueEntry *nd; >> + >> + if (!netdev_is_modern(optarg)) { >> + return -1; >> + } >> + >> + v = qobject_input_visitor_new_str(optarg, "type", &error_fatal); >> + nd = g_new(NetdevQueueEntry, 1); >> + visit_type_Netdev(v, NULL, &nd->nd, &error_fatal); >> + visit_free(v); >> + loc_save(&nd->loc); >> + >> + QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry); >> + >> + return 0; >> +} >> + >> int net_client_parse(QemuOptsList *opts_list, const char *optarg) >> { >> if (!qemu_opts_parse_noisily(opts_list, optarg, true)) { >> diff --git a/softmmu/vl.c b/softmmu/vl.c >> index 8eed0f31c073..838f5b48c447 100644 >> --- a/softmmu/vl.c >> +++ b/softmmu/vl.c >> @@ -2839,7 +2839,8 @@ void qemu_init(int argc, char **argv, char **envp) >> break; >> case QEMU_OPTION_netdev: >> default_net = 0; >> - if (net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { >> + if (netdev_parse_modern(optarg) == -1 && >> + net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { >> exit(1); >> } >> break; > > To make this work, netdev_parse_modern() must > > * either succeeed, or > > * fail without reporting an error, or > > * report an error and exit() > > Recommend to spell that out in its function comment. > > Alternatively: > > if (netdev_is_modern(optarg)) { > netdev_parse_modern(optarg); > } else { > if (net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { > exit(1); > } > } > > netdev_is_modern() needs external linkage, and netdev_parse_modern() > loses its return value. > > Note that all callers net_client_parse() handle failure exactly the same > way. If we let net_client_parse() exit(), then this becomes > > if (netdev_is_modern(optarg)) { > netdev_parse_modern(optarg); > } else { > net_client_parse(qemu_find_opts("netdev"), optarg); > } > > I like this one best. What do you think? > Me too. I wanted to have only entry point in net.c it's why I didn't export netdev_is_modern() but I think it's better to export it not to mix error return (parse has failed) and checking result (is modern or not). And I agree it's more consistent to have both parse functions behaving in the same way (exit or not exit...). I update the patch in that way. Thanks, Laurent
Laurent Vivier <lvivier@redhat.com> writes: > As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field > of Netdev structure can collides with "type" field of SocketAddress), > we introduce a way to bypass qemu_opts_parse_noisily() and use directly > visit_type_Netdev() to parse the backend parameters. > > More details from Markus: > > qemu_init() passes the argument of -netdev, -nic, and -net to > net_client_parse(). > > net_client_parse() parses with qemu_opts_parse_noisily(), passing > QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and > qemu_net_opts for -net. Their desc[] are all empty, which means any > keys are accepted. The result of the parse (a QemuOpts) is stored in > the QemuOptsList. > > Note that QemuOpts is flat by design. In some places, we layer non-flat > on top using dotted keys convention, but not here. > > net_init_clients() iterates over the stored QemuOpts, and passes them to > net_init_netdev(), net_param_nic(), or net_init_client(), respectively. > > These functions pass the QemuOpts to net_client_init(). They also do > other things with the QemuOpts, which we can ignore here. > > net_client_init() uses the opts visitor to convert the (flat) QemOpts to > a (non-flat) QAPI object Netdev. Netdev is also the argument of QMP > command netdev_add. > > The opts visitor was an early attempt to support QAPI in > (QemuOpts-based) CLI. It restricts QAPI types to a certain shape; see > commit eb7ee2cbeb "qapi: introduce OptsVisitor". > > A more modern way to support QAPI is qobject_input_visitor_new_str(). > It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and > it also supports JSON syntax. The former isn't quite as expressive as > JSON, but it's a lot closer than QemuOpts + opts visitor. > > This commit paves the way to use of the modern way instead. > > Signed-off-by: Laurent Vivier <lvivier@redhat.com> > --- > include/net/net.h | 1 + > net/net.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++ > softmmu/vl.c | 3 ++- > 3 files changed, 63 insertions(+), 1 deletion(-) > > diff --git a/include/net/net.h b/include/net/net.h > index c53c64ac18c4..4ae8ed480f73 100644 > --- a/include/net/net.h > +++ b/include/net/net.h > @@ -214,6 +214,7 @@ extern NICInfo nd_table[MAX_NICS]; > extern const char *host_net_devices[]; > > /* from net.c */ > +int netdev_parse_modern(const char *optarg); > int net_client_parse(QemuOptsList *opts_list, const char *str); > void show_netdevs(void); > void net_init_clients(void); > diff --git a/net/net.c b/net/net.c > index 15958f881776..c337d3d753fe 100644 > --- a/net/net.c > +++ b/net/net.c > @@ -54,6 +54,7 @@ > #include "net/colo-compare.h" > #include "net/filter.h" > #include "qapi/string-output-visitor.h" > +#include "qapi/qobject-input-visitor.h" > > /* Net bridge is currently not supported for W32. */ > #if !defined(_WIN32) > @@ -63,6 +64,16 @@ > static VMChangeStateEntry *net_change_state_entry; > static QTAILQ_HEAD(, NetClientState) net_clients; > > +typedef struct NetdevQueueEntry { > + Netdev *nd; > + Location loc; > + QSIMPLEQ_ENTRY(NetdevQueueEntry) entry; > +} NetdevQueueEntry; > + > +typedef QSIMPLEQ_HEAD(, NetdevQueueEntry) NetdevQueue; > + > +static NetdevQueue nd_queue = QSIMPLEQ_HEAD_INITIALIZER(nd_queue); > + > /***********************************************************/ > /* network device redirectors */ > > @@ -1562,6 +1573,20 @@ out: > return ret; > } > > +static void netdev_init_modern(void) > +{ > + while (!QSIMPLEQ_EMPTY(&nd_queue)) { > + NetdevQueueEntry *nd = QSIMPLEQ_FIRST(&nd_queue); > + > + QSIMPLEQ_REMOVE_HEAD(&nd_queue, entry); > + loc_push_restore(&nd->loc); > + net_client_init1(nd->nd, true, &error_fatal); Accepts malformed IDs: $ qemu-system-x86_64 -netdev type=stream,id=_,addr.type=inet,addr.host=localhost,addr.port=1234 qemu-system-x86_64: warning: netdev _ has no peer Compare: $ qemu-system-x86_64 -netdev type=user,id=_ qemu-system-x86_64: -netdev type=user,id=_: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. Calling qmp_netdev_add() instead catches the error. It won't provide the hint, though. Some callers of id_wellformed() do, some don't. Factoring out bool check_id_wellformed(const char *id, Error **errp) could make sense. > + loc_pop(&nd->loc); > + qapi_free_Netdev(nd->nd); > + g_free(nd); > + } > +} > + [...]
diff --git a/include/net/net.h b/include/net/net.h index c53c64ac18c4..4ae8ed480f73 100644 --- a/include/net/net.h +++ b/include/net/net.h @@ -214,6 +214,7 @@ extern NICInfo nd_table[MAX_NICS]; extern const char *host_net_devices[]; /* from net.c */ +int netdev_parse_modern(const char *optarg); int net_client_parse(QemuOptsList *opts_list, const char *str); void show_netdevs(void); void net_init_clients(void); diff --git a/net/net.c b/net/net.c index 15958f881776..c337d3d753fe 100644 --- a/net/net.c +++ b/net/net.c @@ -54,6 +54,7 @@ #include "net/colo-compare.h" #include "net/filter.h" #include "qapi/string-output-visitor.h" +#include "qapi/qobject-input-visitor.h" /* Net bridge is currently not supported for W32. */ #if !defined(_WIN32) @@ -63,6 +64,16 @@ static VMChangeStateEntry *net_change_state_entry; static QTAILQ_HEAD(, NetClientState) net_clients; +typedef struct NetdevQueueEntry { + Netdev *nd; + Location loc; + QSIMPLEQ_ENTRY(NetdevQueueEntry) entry; +} NetdevQueueEntry; + +typedef QSIMPLEQ_HEAD(, NetdevQueueEntry) NetdevQueue; + +static NetdevQueue nd_queue = QSIMPLEQ_HEAD_INITIALIZER(nd_queue); + /***********************************************************/ /* network device redirectors */ @@ -1562,6 +1573,20 @@ out: return ret; } +static void netdev_init_modern(void) +{ + while (!QSIMPLEQ_EMPTY(&nd_queue)) { + NetdevQueueEntry *nd = QSIMPLEQ_FIRST(&nd_queue); + + QSIMPLEQ_REMOVE_HEAD(&nd_queue, entry); + loc_push_restore(&nd->loc); + net_client_init1(nd->nd, true, &error_fatal); + loc_pop(&nd->loc); + qapi_free_Netdev(nd->nd); + g_free(nd); + } +} + void net_init_clients(void) { net_change_state_entry = @@ -1569,6 +1594,8 @@ void net_init_clients(void) QTAILQ_INIT(&net_clients); + netdev_init_modern(); + qemu_opts_foreach(qemu_find_opts("netdev"), net_init_netdev, NULL, &error_fatal); @@ -1579,6 +1606,39 @@ void net_init_clients(void) &error_fatal); } +/* + * netdev_is_modern() returns true when the backend needs to bypass + * qemu_opts_parse_noisily() + */ +static bool netdev_is_modern(const char *optarg) +{ + return false; +} + +/* + * netdev_parse_modern() uses modern, more expressive syntax than + * net_client_parse(), supports only the netdev option. + */ +int netdev_parse_modern(const char *optarg) +{ + Visitor *v; + NetdevQueueEntry *nd; + + if (!netdev_is_modern(optarg)) { + return -1; + } + + v = qobject_input_visitor_new_str(optarg, "type", &error_fatal); + nd = g_new(NetdevQueueEntry, 1); + visit_type_Netdev(v, NULL, &nd->nd, &error_fatal); + visit_free(v); + loc_save(&nd->loc); + + QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry); + + return 0; +} + int net_client_parse(QemuOptsList *opts_list, const char *optarg) { if (!qemu_opts_parse_noisily(opts_list, optarg, true)) { diff --git a/softmmu/vl.c b/softmmu/vl.c index 8eed0f31c073..838f5b48c447 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -2839,7 +2839,8 @@ void qemu_init(int argc, char **argv, char **envp) break; case QEMU_OPTION_netdev: default_net = 0; - if (net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { + if (netdev_parse_modern(optarg) == -1 && + net_client_parse(qemu_find_opts("netdev"), optarg) == -1) { exit(1); } break;
As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field of Netdev structure can collides with "type" field of SocketAddress), we introduce a way to bypass qemu_opts_parse_noisily() and use directly visit_type_Netdev() to parse the backend parameters. More details from Markus: qemu_init() passes the argument of -netdev, -nic, and -net to net_client_parse(). net_client_parse() parses with qemu_opts_parse_noisily(), passing QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and qemu_net_opts for -net. Their desc[] are all empty, which means any keys are accepted. The result of the parse (a QemuOpts) is stored in the QemuOptsList. Note that QemuOpts is flat by design. In some places, we layer non-flat on top using dotted keys convention, but not here. net_init_clients() iterates over the stored QemuOpts, and passes them to net_init_netdev(), net_param_nic(), or net_init_client(), respectively. These functions pass the QemuOpts to net_client_init(). They also do other things with the QemuOpts, which we can ignore here. net_client_init() uses the opts visitor to convert the (flat) QemOpts to a (non-flat) QAPI object Netdev. Netdev is also the argument of QMP command netdev_add. The opts visitor was an early attempt to support QAPI in (QemuOpts-based) CLI. It restricts QAPI types to a certain shape; see commit eb7ee2cbeb "qapi: introduce OptsVisitor". A more modern way to support QAPI is qobject_input_visitor_new_str(). It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and it also supports JSON syntax. The former isn't quite as expressive as JSON, but it's a lot closer than QemuOpts + opts visitor. This commit paves the way to use of the modern way instead. Signed-off-by: Laurent Vivier <lvivier@redhat.com> --- include/net/net.h | 1 + net/net.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++ softmmu/vl.c | 3 ++- 3 files changed, 63 insertions(+), 1 deletion(-)