[libvirt] [PATCH v3 2/4] libxl: channels support
Joao Martins
joao.m.martins at oracle.com
Mon Sep 26 22:48:51 UTC 2016
On 09/26/2016 10:44 PM, Jim Fehlig wrote:
> 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 at oracle.com>
>> ---
>> 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
Argh, sorry about this. In the rush of submitting this before beginning the
freeze, I didn't remember to test the !LIBXL_HAVE_DEVICE_CHANNEL. Previous
versions were good as it had driver being passed which was being also used to
fetch reservedGraphicsPorts.
>
> 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.
Thanks, similar to src/network/bridge_driver.h you probably mean something like
the diff below? It reuses the #ifdef LIBXL_HAVE_DEVICE_CHANNEL already in place
in the patch . Though Your diff follow the general style with LIBXL_HAVE_* and
potentially allows cleaner handling if we were to extend with more more
arguments in libxlBuildDomainConfig or other function. FWIW, both approaches
look good to me.
diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 4c94d54..05745ee 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -1601,6 +1601,14 @@ libxlMakeChannelList(const char *channelDir,
VIR_FREE(x_channels);
return -1;
}
+#else
+static int
+libxlMakeChannelList(const char *channelDir ATTRIBUTE_UNUSED,
+ virDomainDefPtr def ATTRIBUTE_UNUSED,
+ libxl_domain_config *d_config ATTRIBUTE_UNUSED)
+{
+ return 0;
+}
#endif
#ifdef LIBXL_HAVE_PVUSB
@@ -1978,10 +1986,8 @@ libxlBuildDomainConfig(virPortAllocatorPtr graphicsports,
return -1;
#endif
-#ifdef LIBXL_HAVE_DEVICE_CHANNEL
if (libxlMakeChannelList(channelDir, def, d_config) < 0)
return -1;
-#endif
/*
* Now that any potential VFBs are defined, update the build info with
> 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);
>
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