Linux 6.12-rc2: xen-privcmd cannot be loaded in domU anymore

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

Hi,

It looks like xen-privcmd now depends on xen-pciback, and the latter
(expectedly) fails to load in domU with -ENODEV. But that prevents
loading xen-privcmd too. And that's bad.

The dependency looks to be introduced by this commit:

commit 2fae6bb7be320270801b3c3b040189bd7daa8056
Author: Jiqian Chen <Jiqian.Chen@xxxxxxx>
Date:   Tue Sep 24 14:14:37 2024 +0800

    xen/privcmd: Add new syscall to get gsi from dev
    
    On PVH dom0, when passthrough a device to domU, QEMU and xl tools
    want to use gsi number to do pirq mapping, see QEMU code
    xen_pt_realize->xc_physdev_map_pirq, and xl code
    pci_add_dm_done->xc_physdev_map_pirq, but in current codes, the gsi
    number is got from file /sys/bus/pci/devices/<sbdf>/irq, that is
    wrong, because irq is not equal with gsi, they are in different
    spaces, so pirq mapping fails.
    And in current linux codes, there is no method to get gsi
    for userspace.
    
    For above purpose, record gsi of pcistub devices when init
    pcistub and add a new syscall into privcmd to let userspace
    can get gsi when they have a need.
    
    Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
    Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
    Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Message-ID: <20240924061437.2636766-4-Jiqian.Chen@xxxxxxx>
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>


-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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