Re: [Qemu-devel] [PATCH v8 8/8] vmport: Add VMware all ring hack

[Don Slutz <don.slutz@gmail.com>]

On 7/5/2015 2:40 AM, Michael S. Tsirkin wrote:
> On Fri, Jul 03, 2015 at 03:50:19PM +0200, Paolo Bonzini wrote:
>>
>> On 03/07/2015 15:08, Don Slutz wrote:
>>>> Creating it at the pc level and propagating makes code
>>>> messy but I'd go along with it if it made sense from
>>>> user's point of view, but it does not seem to make sense:
>>>> to me this looks more like a CPU feature than a machine property.
>>>> Or the property of the vmport rpc device that you created.
>>> Well this is not a clear area.  It does look more like a CPU feature.  I
>>> went with a machine feature because that is where "vmport" currently is.
>> I think it should be a vmport property.
>>
>> It would be cleaner to implement it using the MemTxAttrs mechanism, but
>> for KVM I'm afraid it would be too slow (and the slowness would affect
>> all I/O accesses, not just vmport ones, unless really ugly hacks are done).
>>
>> Paolo
> Can it ever be implemented for kvm? I couldn't think of a clean way to do it.
>

I do not know of a clean way.  For Xen I need to enable #GP fault 
reporting and add code to check in/out to the magic VMware port.  I 
would assume that some thing similar would be needed in kvm.  Hope this 
helps.

    -Don Slutz