@TeddyAstie @olivierlambert
Thank you sooo much for your prompt response !
FYI a function-level-reset is systematically performed by Xen when doing PCI passthrough, thus your device should be reset before entering another guest (aside reset bugs like you may have).
This is exactly what the problem is. The Dom0 is unable to perform FLR when I also pass vUSB to the Guest. However, if USB is not passed (i mean if it is not attached; even though USB passthrough is enabled in host), the FLR seems to be performed correctly and I am able to restart the guest without problems.
If the FLR is not performed, the Guest (even if it is the same one being restarted) is unable to detect the pass-through cards and also waits for about 136 seconds (about 65.5 seconds for each card) after which it continues without adding the card. This wait time is the kernel default wait time which cannot be changed without rebuilding the kernel I think.
I am trying to find out where the conflict is. (Basically I am unable to understand if this is a driver problem or a Xen problem; since the FLR is being performed correctly when there is no usb being passed through)
Ideally passing USB should not have in impact on PCI-pass through.
Current XAPI uses the approach of having a set of "passthrough-able" devices at boot time by modifying the xen-pciback.hide kernel parameter, which does the same but at boot time.
Will this still work with XCP-ng 8.3 ?
/opt/xensource/libexec/xen-cmdline --set-dom0 "xen-pciback.hide=(0000:07:00.0)"
I am unable to use xe pci-disable-dom0-access uuid=<pci uuid> since UUID for the above pci is not generated (and not visible in xe pci-list)