Re: [PATCH v7 14/16] x86/domain: enable per-domain I/O port bitmaps

[dmukhin@ford.com]

On Tue, Nov 18, 2025 at 08:00:00AM +0200, Mykola Kvach wrote:
[..]

> > +/* Set the default IO Bitmap. */
> > +int ioports_setup_access(struct domain *d)
> > +{
> > +    unsigned int i, offs;
> > +    int rc;
> > +
> > +    if ( pv_shim )
> > +        return 0;
> > +
> > +#ifdef CONFIG_HVM
> 
> ioports_setup_access() now allocates a per-domain io_bitmap for all HVM domains:
> 
> > +    d->arch.hvm.io_bitmap = _xmalloc(HVM_IOBITMAP_SIZE, PAGE_SIZE);
> 
> but I only see this being freed for the hardware domain in the
> existing failure paths.
> Where is io_bitmap freed for non-hardware HVM domains?

Missed that.
I will add something like ioports_release_access() to release resources.

[..]

> >
> > diff --git a/xen/common/emul/vuart/ns16x50.c b/xen/common/emul/vuart/ns16x50.c
> > index c341f012d005..ea34c3ae598a 100644
> > --- a/xen/common/emul/vuart/ns16x50.c
> > +++ b/xen/common/emul/vuart/ns16x50.c
> > @@ -783,9 +783,20 @@ static int ns16x50_init(void *arg)
> >      struct vuart_ns16x50 *vdev = arg;
> >      const struct vuart_info *info = vdev->info;
> >      struct domain *d = vdev->owner;
> > +    int rc;
> >
> >      ASSERT(vdev);
> >
> > +    /* Disallow sharing physical I/O port */
> 
> Should this be undone on teardown and error paths?
> 
> > +    rc = ioports_deny_access(d, info->base_addr,
> > +                             info->base_addr + info->size - 1);
> 

AFAIR, there was a feedback on that during the earlier iterations of the
series and the agreement was - no need to release resources on teardown
since the domain is being destroyed at this point. 

Thanks,
Denis