Re: [libvirt] [PATCH v3 2/4] libxl: channels support

On 09/26/2016 11:33 AM, Joao Martins wrote: > And allow libxl to handle channel element which creates a Xen > console visible to the guest as a low-bandwitdh communication > channel. If type is PTY we also fetch the tty after boot using > libxl_channel_getinfo to fetch the tty path. On socket case, > we autogenerate a path if not specified in the XML. Path autogenerated > is slightly different from qemu driver: qemu stores also on > "channels/target" but it creates then a directory per domain with > each channel target name. libxl doesn't appear to have a clear > definition of private files associated with each domain, so for > simplicity we do it slightly different. On qemu each autogenerated > channel goes like: > > channels/target/<domain-name>/<target name> > > Whereas for libxl: > > channels/target/<domain-name>-<target name> > > Should note that if path is not specified it won't persist, > existing only on live XML, unless user had initially specified it. > Since support for libxl channels only came on Xen >= 4.5 we therefore > need to conditionally compile it with LIBXL_HAVE_DEVICE_CHANNEL. > > After this patch and having a qemu guest agent: > $ cat domain.xml | grep -a1 channel | head -n 5 | tail -n 4 > <channel type='unix'> > <source mode='bind' path='/tmp/channel'/> > <target type='xen' name='org.qemu.guest_agent.0'/> > </channel> > > $ virsh create domain.xml > $ echo '{"execute":"guest-network-get-interfaces"}' | socat > stdio,ignoreeof unix-connect:/tmp/channel > > {"execute":"guest-network-get-interfaces"} > {"return": [{"name": "lo", "ip-addresses": [{"ip-address-type": "ipv4", > "ip-address": "127.0.0.1", "prefix": 8}, {"ip-address-type": "ipv6", > "ip-address": "::1", "prefix": 128}], "hardware-address": > "00:00:00:00:00:00"}, {"name": "eth0", "ip-addresses": > [{"ip-address-type": "ipv4", "ip-address": "10.100.0.6", "prefix": 24}, > {"ip-address-type": "ipv6", "ip-address": "fe80::216:3eff:fe40:88eb", > "prefix": 64}], "hardware-address": "00:16:3e:40:88:eb"}, {"name": > "sit0"}]} > > Signed-off-by: Joao Martins <joao.m.martins(a)oracle.com&gt; > --- > Since v2: > * Remove ret variable and do similar to other make functions. > * Have channelDir passed as an argument instead of driver. > > Since v1: > * Autogenerated paths, and updated commit message explaning it the different > naming. Despite per domain name being slightly different, parent > directory is same across both drivers. > --- > src/libxl/libxl_conf.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++ > src/libxl/libxl_conf.h | 3 ++ > src/libxl/libxl_domain.c | 43 +++++++++++++++++- > src/libxl/libxl_driver.c | 7 +++ > 4 files changed, 162 insertions(+), 1 deletion(-) > > diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c > index 92faa44..4c94d54 100644 > --- a/src/libxl/libxl_conf.c > +++ b/src/libxl/libxl_conf.c > @@ -88,6 +88,7 @@ libxlDriverConfigDispose(void *obj) > VIR_FREE(cfg->saveDir); > VIR_FREE(cfg->autoDumpDir); > VIR_FREE(cfg->lockManagerName); > + VIR_FREE(cfg->channelDir); > virFirmwareFreeList(cfg->firmwares, cfg->nfirmwares); > } > > @@ -1348,6 +1349,8 @@ libxlDriverConfigNew(void) > goto error; > if (VIR_STRDUP(cfg->autoDumpDir, LIBXL_DUMP_DIR) < 0) > goto error; > + if (VIR_STRDUP(cfg->channelDir, LIBXL_CHANNEL_DIR) < 0) > + goto error; > > if (virAsprintf(&log_file, "%s/libxl-driver.log", cfg->logDir) < 0) > goto error; > @@ -1499,6 +1502,107 @@ int libxlDriverConfigLoadFile(libxlDriverConfigPtr cfg, > > } > > +#ifdef LIBXL_HAVE_DEVICE_CHANNEL > +static int > +libxlPrepareChannel(virDomainChrDefPtr channel, > + const char *channelDir, > + const char *domainName) > +{ > + if (channel->targetType == VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_XEN && > + channel->source.type == VIR_DOMAIN_CHR_TYPE_UNIX && > + !channel->source.data.nix.path) { > + if (virAsprintf(&channel->source.data.nix.path, > + "%s/%s-%s", channelDir, domainName, > + channel->target.name ? channel->target.name > + : "unknown.sock") < 0) > + return -1; > + > + channel->source.data.nix.listen = true; > + } > + > + return 0; > +} > + > +static int > +libxlMakeChannel(virDomainChrDefPtr l_channel, > + libxl_device_channel *x_channel) > +{ > + libxl_device_channel_init(x_channel); > + > + if (l_channel->targetType != VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_XEN) { > + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", > + _("channel target type not supported")); > + return -1; > + } > + > + switch (l_channel->source.type) { > + case VIR_DOMAIN_CHR_TYPE_PTY: > + x_channel->connection = LIBXL_CHANNEL_CONNECTION_PTY; > + break; > + case VIR_DOMAIN_CHR_TYPE_UNIX: > + x_channel->connection = LIBXL_CHANNEL_CONNECTION_SOCKET; > + if (VIR_STRDUP(x_channel->u.socket.path, > + l_channel->source.data.nix.path) < 0) > + return -1; > + break; > + default: > + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", > + _("channel source type not supported")); > + break; > + } > + > + if (!l_channel->target.name) { > + virReportError(VIR_ERR_OPERATION_INVALID, "%s", > + _("channel target name missing")); > + return -1; > + } > + > + if (VIR_STRDUP(x_channel->name, l_channel->target.name) < 0) > + return -1; > + > + return 0; > +} > + > +static int > +libxlMakeChannelList(const char *channelDir, > + virDomainDefPtr def, > + libxl_domain_config *d_config) > +{ > + virDomainChrDefPtr *l_channels = def->channels; > + size_t nchannels = def->nchannels; > + libxl_device_channel *x_channels; > + size_t i, nvchannels = 0; > + > + if (VIR_ALLOC_N(x_channels, nchannels) < 0) > + return -1; > + > + for (i = 0; i < nchannels; i++) { > + if (l_channels[i]->deviceType != VIR_DOMAIN_CHR_DEVICE_TYPE_CHANNEL) > + continue; > + > + if (libxlPrepareChannel(l_channels[i], channelDir, def->name) < 0) > + goto error; > + > + if (libxlMakeChannel(l_channels[i], &x_channels[nvchannels]) < 0) > + goto error; > + > + nvchannels++; > + } > + > + VIR_SHRINK_N(x_channels, nchannels, nchannels - nvchannels); > + d_config->channels = x_channels; > + d_config->num_channels = nvchannels; > + > + return 0; > + > + error: > + for (i = 0; i < nchannels; i++) > + libxl_device_channel_dispose(&x_channels[i]); > + VIR_FREE(x_channels); > + return -1; > +} > +#endif > + > #ifdef LIBXL_HAVE_PVUSB > int > libxlMakeUSBController(virDomainControllerDefPtr controller, > @@ -1839,6 +1943,7 @@ libxlDriverNodeGetInfo(libxlDriverPrivatePtr driver, virNodeInfoPtr info) > int > libxlBuildDomainConfig(virPortAllocatorPtr graphicsports, > virDomainDefPtr def, > + const char *channelDir, > libxl_ctx *ctx, > libxl_domain_config *d_config) > { > @@ -1873,6 +1978,11 @@ libxlBuildDomainConfig(virPortAllocatorPtr graphicsports, > return -1; > #endif > > +#ifdef LIBXL_HAVE_DEVICE_CHANNEL > + if (libxlMakeChannelList(channelDir, def, d_config) < 0) > + return -1; > +#endif > + Sorry to report this fails to build if LIBXL_HAVE_DEVICE_CHANNEL is not defined

libxl/libxl_conf.c: In function 'libxlBuildDomainConfig': libxl/libxl_conf.c:1946:36: error: unused parameter 'channelDir' [-Werror=unused-parameter] const char *channelDir, ^ cc1: all warnings being treated as errors Something like the below diff works and minimizes the spread of 'ifdef LIBXL_HAVE_DEVICE_CHANNEL'. Another solution is the approach take e.g. in src/network/bridge_driver.h. Or I'm open to other suggestions.

diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c index 4c94d54..1befd11 100644 --- a/src/libxl/libxl_conf.c +++ b/src/libxl/libxl_conf.c @@ -1943,7 +1943,7 @@ libxlDriverNodeGetInfo(libxlDriverPrivatePtr driver, virNodeInfoPtr info) int libxlBuildDomainConfig(virPortAllocatorPtr graphicsports, virDomainDefPtr def, - const char *channelDir, + const char *channelDir LIBXL_ATTR_UNUSED, libxl_ctx *ctx, libxl_domain_config *d_config) { diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h index 2d60fcc..0ea76b4 100644 --- a/src/libxl/libxl_conf.h +++ b/src/libxl/libxl_conf.h @@ -198,10 +198,15 @@ libxlMakeUSB(virDomainHostdevDefPtr hostdev, libxl_device_usbdev *usbdev); virDomainXMLOptionPtr libxlCreateXMLConf(void); +# ifdef LIBXL_HAVE_DEVICE_CHANNEL +# define LIBXL_ATTR_UNUSED +# else +# define LIBXL_ATTR_UNUSED ATTRIBUTE_UNUSED +# endif int libxlBuildDomainConfig(virPortAllocatorPtr graphicsports, virDomainDefPtr def, - const char *channelDir, + const char *channelDir LIBXL_ATTR_UNUSED, libxl_ctx *ctx, libxl_domain_config *d_config);