https://linux-kvm.org/api.php?action=feedcontributions&feedformat=atom&user=RichardJones 2026-05-09T17:51:50Z User contributions MediaWiki 1.39.5 https://linux-kvm.org/index.php?title=VMchannel_Requirements&diff=2351 2009-06-26T08:55:17Z

<p>RichardJones: typo</p> <hr /> <div>== Requirements ==<br /> <br /> * We want an interface between the guest and the host<br /> <br /> * The channel is to be used for simple communication, like sharing of the clipboard between the user desktop and the guest desktop<br /> ** For relatively low rate of data transfer -- a few MB/s<br /> ** Events to be delivered to the guest, like 'shutdown', 'reboot', 'logoff'<br /> ** Queries to the guest, like 'which users are logged in'<br /> <br /> * Survive live migration<br /> <br /> * Support for multiple agents (consumers of the data) on the guest<br /> <br /> * Multiple channels could be opened at the same time<br /> <br /> * In multi-channels case, one blocked channel shouldn't block communication between others (or one channel shouldn't hog all the bandwidth)<br /> <br /> * Stable ABI (for future upgrades)<br /> <br /> * Channel addressing<br /> ** An agent in the guest should be able to find the channel it's interested in<br /> <br /> * Dynamic channel creation<br /> <br /> * Security<br /> ** No threats to the host<br /> ** Unprivileged user should be able to use the channel<br /> <br /> * Should work out of the box, without any configuration necessary on the part of the guest<br /> <br /> * Notifications of channels being added / removed (hotplugging)<br /> <br /> * An API inside qemu to communicate with agents in the guest<br /> <br /> &lt;br /&gt;<br /> == History ==<br /> A few reasons why the obvious solutions do not work:<br /> <br /> * via the fully emulated serial device.<br /> ** performance (exit per byte)<br /> ** scalability - only 4 serial ports per guest<br /> ** accessed by root only in the guest<br /> <br /> * via TCP/IP network sockets<br /> ** The guest may not have networking enabled<br /> ** The guest firewall may block access to the host IPs<br /> ** Windows can't bind sockets to specific ethernet interfaces<br /> <br /> * via user net &lt;br&gt;http://thread.gmane.org/gmane.comp.emulators.qemu/35780<br /> <br /> * via slirp &lt;br&gt;This implementation does exist upstream as &quot;-net channel&quot; http://www.nabble.com/-PATCH--specify-vmchannel-as-a-net-option-td21911523.html<br /> ** Again, based on networking so same drawbacks mentioned above apply<br /> ** Currently used by [http://libguestfs.org libguestfs]</div>

RichardJones https://linux-kvm.org/index.php?title=VMchannel_Requirements&diff=2350 2009-06-26T08:54:55Z

<p>RichardJones: + note libguestfs is used</p> <hr /> <div>== Requirements ==<br /> <br /> * We want an interface between the guest and the host<br /> <br /> * The channel is to be used for simple communication, like sharing of the clipboard between the user desktop and the guest desktop<br /> ** For relatively low rate of data transfer -- a few MB/s<br /> ** Events to be delivered to the guest, like 'shutdown', 'reboot', 'logoff'<br /> ** Queries to the guest, like 'which users are logged in'<br /> <br /> * Survive live migration<br /> <br /> * Support for multiple agents (consumers of the data) on the guest<br /> <br /> * Multiple channels could be opened at the same time<br /> <br /> * In multi-channels case, one blocked channel shouldn't block communication between others (or one channel shouldn't hog all the bandwidth)<br /> <br /> * Stable ABI (for future upgrades)<br /> <br /> * Channel addressing<br /> ** An agent in the guest should be able to find the channel it's interested in<br /> <br /> * Dynamic channel creation<br /> <br /> * Security<br /> ** No threats to the host<br /> ** Unprivileged user should be able to use the channel<br /> <br /> * Should work out of the box, without any configuration necessary on the part of the guest<br /> <br /> * Notifications of channels being added / removed (hotplugging)<br /> <br /> * An API inside qemu to communicate with agents in the guest<br /> <br /> &lt;br /&gt;<br /> == History ==<br /> A few reasons why the obvious solutions do not work:<br /> <br /> * via the fully emulated serial device.<br /> ** performance (exit per byte)<br /> ** scalability - only 4 serial ports per guest<br /> ** accessed by root only in the guest<br /> <br /> * via TCP/IP network sockets<br /> ** The guest may not have networking enabled<br /> ** The guest firewall may block access to the host IPs<br /> ** Windows can't bind sockets to specific ethernet interfaces<br /> <br /> * via user net &lt;br&gt;http://thread.gmane.org/gmane.comp.emulators.qemu/35780<br /> <br /> * via slirp &lt;br&gt;This implementation does exist upstream as &quot;-net channel&quot; http://www.nabble.com/-PATCH--specify-vmchannel-as-a-net-option-td21911523.html<br /> ** Again, based on networking so same drawbacks mentioned above apply<br /> ** Currently used by [http://libguestfs.org libguestfs]]</div>

RichardJones