Re: [Xen-devel] [PATCH] xen: Fix BUFIOREQ evtchn init for a stubdom.

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2012-06-26 at 11:45 +0100, Anthony PERARD wrote:
> This is a missing part from the previous patch that add the BUFIOREQ_EVTCHN
> parameter. This patch changes the ownership of the buifioreq event channel to
> the stubdom (when HVM_PARAM_DM_DOMAIN is set within the stubdom).
> 
> This fix the initialization of QEMU inside the stubdomain.
> 
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

This fixes stub domains for me, thanks.

The user of this field (hvm_buffered_io_send) takes iorp->lock so we
probably want to put the update inside that too, just like for the
non-buffered case?

It would be nice to extract the alloc&replace functionality into a
helper.

Ian.


> ---
>  xen/arch/x86/hvm/hvm.c |   16 ++++++++++++++++
>  1 files changed, 16 insertions(+), 0 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index e0d495d..9ff1ded 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -3788,6 +3788,22 @@ long do_hvm_op(unsigned long op, 
> XEN_GUEST_HANDLE(void) arg)
>                      /* xchg() ensures that only we free_xen_event_channel() 
> */
>                      old_port = xchg(&v->arch.hvm_vcpu.xen_port, new_port);
>                      free_xen_event_channel(v, old_port);
> +
> +                    if ( v->vcpu_id == 0 )
> +                    {
> +                        new_port = alloc_unbound_xen_event_channel(
> +                            v, a.value, NULL);
> +                        if ( new_port < 0 )
> +                        {
> +                            rc = new_port;
> +                            break;
> +                        }
> +                        old_port = xchg(
> +                            
> &v->domain->arch.hvm_domain.params[HVM_PARAM_BUFIOREQ_EVTCHN],
> +                            new_port);
> +                        free_xen_event_channel(v, old_port);
> +                    }
> +
>                      spin_lock(&iorp->lock);
>                      if ( iorp->va != NULL )
>                          get_ioreq(v)->vp_eport = v->arch.hvm_vcpu.xen_port;



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