Re: [RFC PATCH v3 03/38] xen: Add XEN_DISABLED mode and make it default

[Paul Durrant]

On 16/12/2022 00:40, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
>
> Also check for XEN_ATTACH mode in xen_init()
>
> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>   accel/xen/xen-all.c  | 4 ++++
>   include/hw/xen/xen.h | 5 +++--
>   2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/accel/xen/xen-all.c b/accel/xen/xen-all.c
> index 69aa7d018b..109d2e84bc 100644
> --- a/accel/xen/xen-all.c
> +++ b/accel/xen/xen-all.c
> @@ -158,6 +158,10 @@ static int xen_init(MachineState *ms)
>   {
>       MachineClass *mc = MACHINE_GET_CLASS(ms);
>   
> +    if (xen_mode != XEN_ATTACH) {
> +        xen_pv_printf(NULL, 0, "xen requires --xen-attach mode\n");
> +        return -1;
> +    }

This is new requirement, isn't it? Libxl only passes --xen-attach
for PV domains so AFAICT this will break Xen HVM domains.

  Paul

>       xen_xc = xc_interface_open(0, 0, 0);
>       if (xen_xc == NULL) {
>           xen_pv_printf(NULL, 0, "can't open xen interface\n");
> diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
> index afdf9c436a..82347e76a4 100644
> --- a/include/hw/xen/xen.h
> +++ b/include/hw/xen/xen.h
> @@ -12,8 +12,9 @@
>   
>   /* xen-machine.c */
>   enum xen_mode {
> -    XEN_EMULATE = 0,  // xen emulation, using xenner (default)
> -    XEN_ATTACH        // attach to xen domain created by libxl
> +    XEN_DISABLED = 0, // xen support disabled (default)
> +    XEN_ATTACH,       // attach to xen domain created by libxl
> +    XEN_EMULATE,
>   };
>   
>   extern uint32_t xen_domid;