Re: [QEMU][PATCH v4 06/10] hw/xen/xen-hvm-common: skip ioreq creation on ioreq registration failure

[Stefano Stabellini]

On Wed, 25 Jan 2023, Vikram Garhwal wrote:
> From: Stefano Stabellini <stefano.stabellini@amd.com>
> 
> On ARM it is possible to have a functioning xenpv machine with only the
> PV backends and no IOREQ server. If the IOREQ server creation fails continue
> to the PV backends initialization.
> 
> Also, moved the IOREQ registration and mapping subroutine to new function
> xen_do_ioreq_register().
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
> Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>

as per my previous reply, even though I am listed as co-author, for
tracking that I did review this version of the patch:

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
>  hw/xen/xen-hvm-common.c | 53 ++++++++++++++++++++++++++++-------------
>  1 file changed, 36 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/xen/xen-hvm-common.c b/hw/xen/xen-hvm-common.c
> index e748d8d423..94dbbe97ed 100644
> --- a/hw/xen/xen-hvm-common.c
> +++ b/hw/xen/xen-hvm-common.c
> @@ -777,25 +777,12 @@ err:
>      exit(1);
>  }
>  
> -void xen_register_ioreq(XenIOState *state, unsigned int max_cpus,
> -                        MemoryListener xen_memory_listener)
> +static void xen_do_ioreq_register(XenIOState *state,
> +                                           unsigned int max_cpus,
> +                                           MemoryListener 
> xen_memory_listener)
>  {
>      int i, rc;
>  
> -    state->xce_handle = xenevtchn_open(NULL, 0);
> -    if (state->xce_handle == NULL) {
> -        perror("xen: event channel open");
> -        goto err;
> -    }
> -
> -    state->xenstore = xs_daemon_open();
> -    if (state->xenstore == NULL) {
> -        perror("xen: xenstore open");
> -        goto err;
> -    }
> -
> -    xen_create_ioreq_server(xen_domid, &state->ioservid);
> -
>      state->exit.notify = xen_exit_notifier;
>      qemu_add_exit_notifier(&state->exit);
>  
> @@ -859,12 +846,44 @@ void xen_register_ioreq(XenIOState *state, unsigned int 
> max_cpus,
>      QLIST_INIT(&state->dev_list);
>      device_listener_register(&state->device_listener);
>  
> +    return;
> +
> +err:
> +    error_report("xen hardware virtual machine initialisation failed");
> +    exit(1);
> +}
> +
> +void xen_register_ioreq(XenIOState *state, unsigned int max_cpus,
> +                        MemoryListener xen_memory_listener)
> +{
> +    int rc;
> +
> +    state->xce_handle = xenevtchn_open(NULL, 0);
> +    if (state->xce_handle == NULL) {
> +        perror("xen: event channel open");
> +        goto err;
> +    }
> +
> +    state->xenstore = xs_daemon_open();
> +    if (state->xenstore == NULL) {
> +        perror("xen: xenstore open");
> +        goto err;
> +    }
> +
> +    rc = xen_create_ioreq_server(xen_domid, &state->ioservid);
> +    if (!rc) {
> +        xen_do_ioreq_register(state, max_cpus, xen_memory_listener);
> +    } else {
> +        warn_report("xen: failed to create ioreq server");
> +    }
> +
>      xen_bus_init();
>  
>      xen_register_backend(state);
>  
>      return;
> +
>  err:
> -    error_report("xen hardware virtual machine initialisation failed");
> +    error_report("xen hardware virtual machine backend registration failed");
>      exit(1);
>  }
> -- 
> 2.17.0
> 
>