Re: [PATCH for-4.5 v6 05/16] tools: Add vmware_port support

[Don Slutz <dslutz@verizon.com>]

On 09/25/14 07:24, Ian Campbell wrote:
> On Wed, 2014-09-24 at 12:31 -0400, Don Slutz wrote:
>> On 09/23/14 08:20, Ian Campbell wrote:
>>> On Mon, 2014-09-22 at 12:42 -0400, Don Slutz wrote:

[snip]

>>> And vmware_port is not ignored. 
>>> What I suggested was "if vmware_hw is non-zero then set vmware_port".
>>>
>> I am reading that as "set vmware_port if not specified".  To avoid
>> complexity, I am treating vmware_hw as a boolean.  Using this
>> I get the following table:
>>
>> _hw   _port
>>    0     0        Just like today
>>    1     0        Only cpuid leaves change -- very unlikey
>>    1     1        Full VMware mode
>>    0     1        VMware hyper call mode.
>>
>> Adding U for unspecified:
>>
>> _hw   _port
>>    U     U        ==> _hw=0 _port=0
>>    0     U        ==> _hw=0 _port=0
>>    1     U        The case in question.
>>    U     0        ==> _hw=0 _port=0
>>    U     1        What I was talking about.
>>    0     0        Just like today
>>    1     0        Only cpuid leaves change -- very unlikey
>>    1     1        Full VMware mode
>>    0     1        VMware hyper call mode.
>>
>> The problem here is that vmware_hw is not a boolean and there is
>> currently not a value that lets you know it has not been specified.
> The unspecified value is 0, surely? All of the rows with U under _hw can
> be ignored, I am talking only about _port being a defbool.
>
>    0     U        ==> _hw=0 _port=0
>    1     U        The case in question.
>
> => libxl should convert U to 1.
>
>    0     0        Just like today
>    1     0        Only cpuid leaves change -- very unlikey
>    1     1        Full VMware mode
>    0     1        VMware hyper call mode.
>
> All reasonable things to ask for explicitly, I think (I'm not so sure
> about the last one, might be an error?).
>

This is not an error as far as VMware says in "Mechanisms to determine
if software is running in a VMware virtual machine":

*Recommended code*

int Detect_VMware(void)
{
         if (cpuid_check())
                 return 1;               // Success running under VMware.
         else if (dmi_check() && hypervisor_port_check())
                 return 1;
         return 0;
}



If there is code that has issues with Xen in cpuid leaves and VMware port
"working", then yes this is a bad config to pick.

    -Don Slutz