Hi, I'm currently debugging why hotplugging pci devices doesn't work with the linux based stubdom used in the next Qubes release (based on Anthony's and Eric's patches).
When attaching a pci device to a running domain qemu in the stubdom throws the following error: [00:06.0] xen_pt_region_update: Error: create new mem mapping failed! (err: 1) It seems that the problem is that do_pci_add first triggers the qemu device_add command (via xenstore or qmp) and then calls xc_domain_iomem_permission. So when qemu calls xc_domain_memory_mapping during the setup of the device it fails because the permissions aren't configured yet. When I just move the qemu device_add further down it indeed works. This problem does not appear when running qemu in dom0. Probably because dom0 has anyway permission to call xc_domain_memory_mapping. I don't understand why this is not a problem for minios based stubdoms. Maybe just timing? Does the above analysis sounds correct? (I'm not really familiar with this). If yes, where exactly should the qemu pci_add be moved? Thanks.
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