Re: [PULL 13/27] hw/xen: Add xenstore operations to allow redirection to internal emulation

[Jason Andryuk <jandryuk@xxxxxxxxx>]

On Tue, Mar 7, 2023 at 1:29 PM David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote:
>
> From: Paul Durrant <pdurrant@xxxxxxxxxx>
>
> Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
> Reviewed-by: Paul Durrant <paul@xxxxxxx>
> ---
>  accel/xen/xen-all.c                 |  11 +-
>  hw/char/xen_console.c               |   2 +-
>  hw/i386/kvm/xen_xenstore.c          |   3 -
>  hw/i386/kvm/xenstore_impl.h         |   8 +-
>  hw/xen/xen-bus-helper.c             |  62 +++----
>  hw/xen/xen-bus.c                    | 261 ++++------------------------
>  hw/xen/xen-legacy-backend.c         | 119 +++++++------
>  hw/xen/xen-operations.c             | 198 +++++++++++++++++++++
>  hw/xen/xen_devconfig.c              |   4 +-
>  hw/xen/xen_pt_graphics.c            |   1 -
>  hw/xen/xen_pvdev.c                  |  49 +-----
>  include/hw/xen/xen-bus-helper.h     |  26 +--
>  include/hw/xen/xen-bus.h            |  17 +-
>  include/hw/xen/xen-legacy-backend.h |   6 +-
>  include/hw/xen/xen_backend_ops.h    | 163 +++++++++++++++++
>  include/hw/xen/xen_common.h         |   1 -
>  include/hw/xen/xen_pvdev.h          |   2 +-
>  softmmu/globals.c                   |   1 +
>  18 files changed, 525 insertions(+), 409 deletions(-)
>
> diff --git a/accel/xen/xen-all.c b/accel/xen/xen-all.c
> index e85e4aeba5..425216230f 100644
> --- a/accel/xen/xen-all.c
> +++ b/accel/xen/xen-all.c
> @@ -90,12 +90,15 @@ void xenstore_store_pv_console_info(int i, Chardev *chr)
>  }
>
>
> -static void xenstore_record_dm_state(struct xs_handle *xs, const char *state)
> +static void xenstore_record_dm_state(const char *state)
>  {
> +    struct xs_handle *xs;
>      char path[50];
>
> +    /* We now have everything we need to set the xenstore entry. */
> +    xs = xs_open(0);
>      if (xs == NULL) {
> -        error_report("xenstore connection not initialized");
> +        fprintf(stderr, "Could not contact XenStore\n");
>          exit(1);
>      }

This breaks dm_restrict=1 since the xs_open is not allowed by the time
this is called.  There are other evtchn errors before this as well:
# cat /var/log/xen/qemu-dm-debian.log
char device redirected to /dev/pts/8 (label serial0)
xen be core: can't open evtchn device
xen be core: can't open evtchn device
xen be core: can't open evtchn device
xen be core: can't open evtchn device
xen be core: can't open evtchn device
xen be core: can't open evtchn device
xen be core: can't open evtchn device
xen be core: can't open evtchn device
Could not contact XenStore

Ok, those "xen be core: can't open evtchn device" were there before
the recent changes and seem to be non-fatal.

Regards,
Jason