<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <style type="text/css" style="display:none;"></style> </head> <body dir="ltr"> <div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;" dir="ltr"> <p>The Nehalem era X58, 5500 and 5520 Chipsets had a notoriously broken Interrupt Remapping implementation:<br> <a href="https://support.citrix.com/article/CTX136517" class="OWAAutoLink" id="LPlnk314059" previewremoved="true">https://support.citrix.com/article/CTX136517</a> (Love that <span>symptoms </span>list)<br> <a href="https://www.netiq.com/support/kb/doc.php?id=7014344" class="OWAAutoLink" id="LPlnk377385" previewremoved="true">https://www.netiq.com/support/kb/doc.php?id=7014344</a><br> <a href="https://serverfault.com/questions/745593/does-disabling-vt-d-and-interrupt-remapping-break-msi-x" class="OWAAutoLink" id="LPlnk620398" previewremoved="true">https://serverfault.com/questions/745593/does-disabling-vt-d-and-interrupt-remapping-break-msi-x</a><br> <br> <br> </p> Interrupt Remapping was directly related to some x2APIC, MSI-X (Not sure if MSI) and IOMMU features which obviously on X58 platforms don't work as intended. You can try to force disabling them with Kernel Parameters (intremap=off and something else to force old xAPIC) and see if it improves. Google around also the X2APIC Disable Bit in the ACPI DMAR Table (I recall that I wrote something related to it). VFIO had also an allow_unsafe_interrupts=1 option that was also related to Nehalem broken Chipsets.<br> Basically, you have trying to use early era Hardware that was quite buggy, so is expected that Passthrough would be problematic. Have fun!</div> </body> </html>