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<p class="MsoNormal">Hello:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We found the causes for this issue: QEMU does not connect the socket for sending event until enters into its main_loop if libvirt uses "nowait" to create the chardev for monitor; And qemu cannot send event until it receives the first qmp
cmd: qmp_capabilities. So We cannot send event from qemu before these conditions met.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">To overcome these restrictions I think we either:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">1: Change qemu implementation to send the event after receives qmp_capabilities cmd and socket connection is setup. This will require some major changes on qemu.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Or:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">2: Implement a new qmp cmd that libvirt will use to query sev_measurement from qemu after issues qmp_capabilities cmd, but before resume VM. Sev_measurement value will be sent back from qemu as response for this new qmp cmd.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We would like to know what do you think about these two methods? Which method do you prefer? Thank you.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards<o:p></o:p></p>
<p class="MsoNormal">Xiaogang<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> Chen, Xiaogang <br>
<b>Sent:</b> Thursday, January 18, 2018 2:01 PM<br>
<b>To:</b> 'libvir-list@redhat.com' <libvir-list@redhat.com><br>
<b>Cc:</b> Singh, Brijesh <brijesh.singh@amd.com>; Lendacky, Thomas <Thomas.Lendacky@amd.com><br>
<b>Subject:</b> a libvirt event question<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hello:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoPlainText">We are adding libvirt functions to launch SEV VM. When start VM I put it at “pause” state. During that time qemu sends an event “sev_measurement”. We hope libvirtd get this event before we resume VM. But I did not see libvirtd receive
it. If I send this event at qemu during resume time libvirtd can get this event successfully. I traced qemuMonitorJSONIOProcessEvent function for events received, did not see any event coming before resume VM.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Is there something I missed to get this event during pause state? Thank you for your help.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Regards<o:p></o:p></p>
<p class="MsoPlainText">Xiaogang<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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