hyperv/vmbus: also find acpi_syscontainer0 for _CRS

[decui_microsoft.com]

Summary

This is needed for PCIe pass-through on Hyper-V Generation 2 VM.

[jhb]

Humm, ok I guess. This is a gross hack though that would be fixed by making vmbus a child of whatever device it belongs to. Also, it seems like you should be trying to find _CRS on your parent in the namespace. That wouldn't be on acpi0, but instead you would use something like:

ACPI_STATUS status;
ACPI_HANDLE handle;

status = AcpiGetParent(acpi_get_handle(dev), &handle);
if (ACPI_SUCCESS(status)) {
    device_t parent;

    parent = acpi_get_device(handle);
    if (parent != NULL)
        vmbus_get_crs(parent, dev, pass);
}

This would find the parent of the VMBus device in the ACPI namespace and use that device's device_t.

[decui_microsoft.com]

Sephe will send out a patchset that will handle the issue in a better way.