Re: [PATCH] tools/libxc: Set HVM_PARAM_CONSOLE_EVTCHN during restore

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 23/04/15 03:49, Boris Ostrovsky wrote:
> When resuming, the guest needs to check whether the port has changed. HVM
> guests use this parameter to get the port number.
>
> (We can't always use xenstore where this value is also written: for example
> on Linux the console is resumed very early, before the store is up).
>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

This bug is also present in migration v2 but mitigated in our case
because of the binary we use to call xc_domain_restore() which also sets
the evtchn up.

I believe libxl is also fine for the same reason, but I will fix it
nevertheless.

~Andrew

> ---
>  tools/libxc/xc_domain_restore.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
> index 2ab9f46..f9dfd2d 100644
> --- a/tools/libxc/xc_domain_restore.c
> +++ b/tools/libxc/xc_domain_restore.c
> @@ -2328,7 +2328,10 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
>                                      HVM_PARAM_PAE_ENABLED, pae))
>           || (frc = xc_hvm_param_set(xch, dom,
>                                      HVM_PARAM_STORE_EVTCHN,
> -                                    store_evtchn)) )
> +                                    store_evtchn))
> +         || (frc = xc_hvm_param_set(xch, dom,
> +                                    HVM_PARAM_CONSOLE_EVTCHN,
> +                                    console_evtchn)) )
>      {
>          PERROR("error setting HVM params: %i", frc);
>          goto out;