Re: [Xen-devel] [PATCH] xen/pvh: trap access to IO port range 0xcf8-0xcfb

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.05.15 at 12:00, <roger.pau@xxxxxxxxxx> wrote:
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -1527,7 +1527,7 @@ static int __hwdom_init io_bitmap_cb(unsigned long s, 
> unsigned long e,
>  
>  void __hwdom_init setup_io_bitmap(struct domain *d)
>  {
> -    int rc;
> +    int rc, i;

The new variable ought to be of unsigned type and could go
into the more narrow scope it's needed in.

> @@ -1535,6 +1535,12 @@ void __hwdom_init setup_io_bitmap(struct domain *d)
>          rc = rangeset_report_ranges(d->arch.ioport_caps, 0, 0x10000,
>                                      io_bitmap_cb, d);
>          BUG_ON(rc);
> +        /*
> +         * NB: we need to trap accesses to the range 0xcf8-0xcfb in order
> +         * to intercept 4 byte accesses.
> +         */
> +        for ( i = 0xcf8; i < 0xcfc; i++ )
> +            __set_bit(i, d->arch.hvm_domain.io_bitmap);

To achieve what the comment says you'd really only need to
set any one of the four bits.

Jan


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