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

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 05/01/17 12:15, Jan Beulich wrote:
>>>> 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 it is.  Will fix.

> so with that adjusted
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Thanks.

~Andrew

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