qemu: Generate shorter channel target paths

A <channel/> device is basically an UNIX socket into guest.
Whatever is sent from the host, appears in the guest and vice
versa. But because of that, the length of the path to the socket
is important (underscored by fact that we derive the path from
domain short name). But there are still cases where we might not
fit into UNIX_PATH_MAX limit (usually 108 characters), because
the path is derived also from other variables, e.g.
XDG_CONFIG_HOME for session domains.

There are two components though, that are needless: "/target/"
and "domain-" prefix. Drop them. This is safe to do, because
running domains have their path saved in status XML and even
though paths are dropped on migration, they are not part of guest
ABI and thus we are free to change them.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
This commit is contained in:
Michal Privoznik 2023-04-18 17:34:12 +02:00
parent 5d8e842a0f
commit d3759d3674
12 changed files with 31 additions and 16 deletions

View File

@ -2136,7 +2136,6 @@ exit 0
%ghost %dir %{_rundir}/libvirt/qemu/swtpm/
%dir %attr(0751, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/
%dir %attr(0751, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/channel/
%dir %attr(0751, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/channel/target/
%dir %attr(0751, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/checkpoint/
%dir %attr(0751, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/dump/
%dir %attr(0751, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/nvram/

View File

@ -151,7 +151,7 @@ virQEMUDriverConfig *virQEMUDriverConfigNew(bool privileged,
cfg->snapshotDir = g_strdup_printf("%s/snapshot", cfg->libDir);
cfg->checkpointDir = g_strdup_printf("%s/checkpoint", cfg->libDir);
cfg->autoDumpPath = g_strdup_printf("%s/dump", cfg->libDir);
cfg->channelTargetDir = g_strdup_printf("%s/channel/target", cfg->libDir);
cfg->channelTargetDir = g_strdup_printf("%s/channel", cfg->libDir);
cfg->nvramDir = g_strdup_printf("%s/nvram", cfg->libDir);
cfg->memoryBackingDir = g_strdup_printf("%s/ram", cfg->libDir);
} else if (privileged) {
@ -173,7 +173,7 @@ virQEMUDriverConfig *virQEMUDriverConfigNew(bool privileged,
cfg->snapshotDir = g_strdup_printf("%s/snapshot", cfg->libDir);
cfg->checkpointDir = g_strdup_printf("%s/checkpoint", cfg->libDir);
cfg->autoDumpPath = g_strdup_printf("%s/dump", cfg->libDir);
cfg->channelTargetDir = g_strdup_printf("%s/channel/target", cfg->libDir);
cfg->channelTargetDir = g_strdup_printf("%s/channel", cfg->libDir);
cfg->nvramDir = g_strdup_printf("%s/nvram", cfg->libDir);
cfg->memoryBackingDir = g_strdup_printf("%s/ram", cfg->libDir);
cfg->swtpmStorageDir = g_strdup_printf("%s/lib/libvirt/swtpm",
@ -201,7 +201,7 @@ virQEMUDriverConfig *virQEMUDriverConfigNew(bool privileged,
cfg->checkpointDir = g_strdup_printf("%s/qemu/checkpoint",
cfg->configBaseDir);
cfg->autoDumpPath = g_strdup_printf("%s/qemu/dump", cfg->configBaseDir);
cfg->channelTargetDir = g_strdup_printf("%s/qemu/channel/target",
cfg->channelTargetDir = g_strdup_printf("%s/qemu/channel",
cfg->configBaseDir);
cfg->nvramDir = g_strdup_printf("%s/qemu/nvram", cfg->configBaseDir);
cfg->memoryBackingDir = g_strdup_printf("%s/qemu/ram", cfg->configBaseDir);

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@ -1780,7 +1780,7 @@ qemuDomainSetPrivatePaths(virQEMUDriver *driver,
priv->libDir = g_strdup_printf("%s/domain-%s", cfg->libDir, domname);
if (!priv->channelTargetDir)
priv->channelTargetDir = g_strdup_printf("%s/domain-%s",
priv->channelTargetDir = g_strdup_printf("%s/%s",
cfg->channelTargetDir, domname);
return 0;
@ -5405,13 +5405,16 @@ qemuDomainDefaultNetModel(const virDomainDef *def,
* Clear auto generated unix socket paths:
*
* libvirt 1.2.18 and older:
* {cfg->channelTargetDir}/{dom-name}.{target-name}
* {cfg->channelTargetDir}/target/{dom-name}.{target-name}
*
* libvirt 1.2.19 - 1.3.2:
* {cfg->channelTargetDir}/domain-{dom-name}/{target-name}
* {cfg->channelTargetDir}/target/domain-{dom-name}/{target-name}
*
* libvirt 1.3.3 and newer:
* {cfg->channelTargetDir}/domain-{dom-id}-{short-dom-name}/{target-name}
* libvirt 1.3.3 - 9.7.0:
* {cfg->channelTargetDir}/target/domain-{dom-id}-{short-dom-name}/{target-name}
*
* libvirt 9.7.0 and newer:
* {cfg->channelTargetDir}/{dom-id}-{short-dom-name}/{target-name}
*
* The unix socket path was stored in config XML until libvirt 1.3.0.
* If someone specifies the same path as we generate, they shouldn't do it.
@ -5437,7 +5440,7 @@ qemuDomainChrDefDropDefaultPath(virDomainChrDef *chr,
cfg = virQEMUDriverGetConfig(driver);
virBufferEscapeRegex(&buf, "^%s", cfg->channelTargetDir);
virBufferAddLit(&buf, "/([^/]+\\.)|(domain-[^/]+/)");
virBufferAddLit(&buf, "/(target/)?([^/]+\\.)|(domain-[^/]+/)|([0-9]+-[^/]+/)");
virBufferEscapeRegex(&buf, "%s$", chr->target.name);
regexp = virBufferContentAndReset(&buf);

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@ -1,5 +1,5 @@
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/target/domain-7-hotplug/org.qemu.guest_agent.0'/>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/7-hotplug/org.qemu.guest_agent.0'/>
<target type='virtio' name='org.qemu.guest_agent.0'/>
<address type='virtio-serial' controller='0' bus='0' port='1'/>
</channel>

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@ -39,7 +39,7 @@
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
</controller>
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/target/domain-7-hotplug/org.qemu.guest_agent.0'/>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/7-hotplug/org.qemu.guest_agent.0'/>
<target type='virtio' name='org.qemu.guest_agent.0'/>
<alias name='channel0'/>
<address type='virtio-serial' controller='0' bus='0' port='1'/>

View File

@ -39,7 +39,7 @@
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
</controller>
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/target/domain-7-hotplug/org.qemu.guest_agent.0'/>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/domain-7-hotplug/org.qemu.guest_agent.0'/>
<target type='virtio' name='org.qemu.guest_agent.0'/>
<alias name='channel0'/>
<address type='virtio-serial' controller='0' bus='0' port='1'/>

View File

@ -39,7 +39,7 @@
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
</controller>
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/target/domain-7-hotplug/org.qemu.guest_agent.0'/>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/7-hotplug/org.qemu.guest_agent.0'/>
<target type='virtio' name='org.qemu.guest_agent.0'/>
<alias name='channel0'/>
<address type='virtio-serial' controller='0' bus='0' port='1'/>

View File

@ -42,7 +42,7 @@
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
</controller>
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/target/domain-7-hotplug/org.qemu.guest_agent.0'/>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/7-hotplug/org.qemu.guest_agent.0'/>
<target type='virtio' name='org.qemu.guest_agent.0'/>
<alias name='channel0'/>
<address type='virtio-serial' controller='0' bus='0' port='1'/>

View File

@ -24,6 +24,10 @@
<source mode='bind' path='/var/lib/libvirt/qemu/channel/target/QEMUGuest1/org.qemu.guest_agent.3'/>
<target type='virtio' name='org.qemu.guest_agent.3'/>
</channel>
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/1-QEMUGuest1/org.qemu.guest_agent.4'/>
<target type='virtio' name='org.qemu.guest_agent.4'/>
</channel>
<memballoon model='none'/>
</devices>
</domain>

View File

@ -41,6 +41,11 @@
<target type='virtio' name='org.qemu.guest_agent.3'/>
<address type='virtio-serial' controller='0' bus='0' port='4'/>
</channel>
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/channel/1-QEMUGuest1/org.qemu.guest_agent.4'/>
<target type='virtio' name='org.qemu.guest_agent.4'/>
<address type='virtio-serial' controller='0' bus='0' port='5'/>
</channel>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<audio id='1' type='none'/>

View File

@ -38,6 +38,10 @@
<target type='virtio' name='org.qemu.guest_agent.3'/>
<address type='virtio-serial' controller='0' bus='0' port='4'/>
</channel>
<channel type='unix'>
<target type='virtio' name='org.qemu.guest_agent.4'/>
<address type='virtio-serial' controller='0' bus='0' port='5'/>
</channel>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<audio id='1' type='none'/>

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@ -460,7 +460,7 @@ int qemuTestDriverInit(virQEMUDriver *driver)
VIR_FREE(cfg->libDir);
cfg->libDir = g_strdup("/var/lib/libvirt/qemu");
VIR_FREE(cfg->channelTargetDir);
cfg->channelTargetDir = g_strdup("/var/lib/libvirt/qemu/channel/target");
cfg->channelTargetDir = g_strdup("/var/lib/libvirt/qemu/channel");
VIR_FREE(cfg->memoryBackingDir);
cfg->memoryBackingDir = g_strdup("/var/lib/libvirt/qemu/ram");
VIR_FREE(cfg->nvramDir);