Re: [PATCH v2 4/4] hw/xen: Have Xen machines select 9pfs

[Paolo Bonzini]

On 01/02/21 10:18, Philippe Mathieu-Daudé wrote:
> FYI using 'imply FSDEV_9P' instead I get:
>
> /usr/bin/ld: libcommon.fa.p/hw_xen_xen-legacy-backend.c.o: in function
> `xen_be_register_common':
> hw/xen/xen-legacy-backend.c:754: undefined reference to `xen_9pfs_ops'

Ok, so then we have the case of a file (hw/xen/xen-legacy-backend.c) 
brought in by CONFIG_XEN.  In that case this patch is incorrect...

> The function is:
>
>    void xen_be_register_common(void)
>    {
>        xen_set_dynamic_sysbus();
>
>        xen_be_register("console", &xen_console_ops);
>        xen_be_register("vkbd", &xen_kbdmouse_ops);
>    #ifdef CONFIG_VIRTFS
>        xen_be_register("9pfs", &xen_9pfs_ops);
>    #endif
>    #ifdef CONFIG_USB_LIBUSB
>        xen_be_register("qusb", &xen_usb_ops);
>    #endif
>    }
>
> The object is compiled using:
>
> -- >8 --
> -#ifdef CONFIG_VIRTFS
> +#ifdef CONFIG_FSDEV_9P
>       xen_be_register("9pfs", &xen_9pfs_ops);
>   #endif
> ---

... and this is the best fix, together with:

- a "#include CONFIG_DEVICES" at the top (to get CONFIG_FSDEV_9P)

- moving xen-legacy-backend.c from softmmu_ss to specific_ss (to get 
CONFIG_DEVICES)

- changing "select" to "imply" in accel/Kconfig (otherwise the patch has 
no effect)

But really, doing nothing and just dropping this patch is perfectly fine.

Paolo