Re: [Qemu-devel] [PATCH 3/6] xen: Skip backend initialization for stubdom

[Paul Durrant]

> -----Original Message-----
> From: Jason Andryuk [mailto:address@hidden
> Sent: 11 March 2019 18:02
> To: address@hidden
> Cc: address@hidden; address@hidden; Jason Andryuk
> <address@hidden>; Stefano Stabellini <address@hidden>; Anthony Perard
> <address@hidden>; Paul Durrant <address@hidden>; Paolo Bonzini
> <address@hidden>; Richard Henderson <address@hidden>; Eduardo Habkost 
> <address@hidden>;
> Michael S. Tsirkin <address@hidden>; Marcel Apfelbaum <address@hidden>
> Subject: [PATCH 3/6] xen: Skip backend initialization for stubdom
> 
> When QEMU is running in a stubdom, it does not provide any
> Paravirtualized backends.  Those still run in dom0 or another driver
> domain.  Therefore we skip backend initialization (xen_bus_init and
> xen_be_init) for the stubdom case.
> 
> Original patch by Anthony PERARD <address@hidden>
> 
> Signed-off-by: Jason Andryuk <address@hidden>

Reviewed-by: Paul Durrant <address@hidden>

> ---
>  hw/i386/xen/xen-hvm.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
> index c20c4b27f6..4b62f070cb 100644
> --- a/hw/i386/xen/xen-hvm.c
> +++ b/hw/i386/xen/xen-hvm.c
> @@ -1485,8 +1485,6 @@ void xen_hvm_init(PCMachineState *pcms, MemoryRegion 
> **ram_memory)
>      QLIST_INIT(&state->dev_list);
>      device_listener_register(&state->device_listener);
> 
> -    xen_bus_init();
> -
>      xenstore = xs_open(0);
>      if (!xenstore) {
>          error_report("Can't connect to xenstored");
> @@ -1495,12 +1493,16 @@ void xen_hvm_init(PCMachineState *pcms, MemoryRegion 
> **ram_memory)
> 
>      qemu_set_fd_handler(xs_fileno(xenstore), xenstore_update, NULL, NULL);
> 
> -    /* Initialize backend core & drivers */
> -    if (xen_be_init() != 0) {
> -        error_report("xen backend core setup failed");
> -        goto err;
> +    if (!xen_stubdom_enabled()) {
> +        xen_bus_init();
> +
> +        /* Initialize backend core & drivers */
> +        if (xen_be_init() != 0) {
> +            error_report("xen backend core setup failed");
> +            goto err;
> +        }
> +        xen_be_register_common();
>      }
> -    xen_be_register_common();
> 
>      QLIST_INIT(&xen_physmap);
>      xen_read_physmap(state);
> --
> 2.20.1