Re: [Xen-devel] [PATCH 2/2] x86/pv: Defer I/O bitmap checks even in 64bit mode for emulate_privilege_op()

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 05.01.17 at 13:00, <andrew.cooper3@xxxxxxxxxx> wrote:
> --- a/xen/arch/x86/traps.c
> +++ b/xen/arch/x86/traps.c
> @@ -2169,6 +2169,19 @@ static int priv_op_read_segment(enum x86_segment seg,
>                                  struct segment_register *reg,
>                                  struct x86_emulate_ctxt *ctxt)
>  {
> +    /* Check if this is an attempt to access to I/O bitmap. */
> +    if ( seg == x86_seg_tr )
> +    {
> +        switch ( ctxt->opcode )
> +        {
> +        case 0x6c ... 0x6f: /* ins / outs */
> +        case 0xe4 ... 0xe7: /* in / out (immediate port) */
> +        case 0xec ... 0xef: /* in / out (port in %dx) */
> +            /* Defer the check to priv_op_{read,write}_io(). */
> +            return X86EMUL_DONE;
> +        }
> +    }

Well, I think I did like the old way a little better, but if you prefer this
switch(), then fine. When putting together my variant of the change for
testing I did notice the comment to have a wrong "to" (should be "the"),
so with that adjusted
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan


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