On 03/08/2010 03:03 PM, Paul Brook wrote:
quoted text
>> On 03/08/2010 12:53 AM, Paul Brook wrote:
>>      
>>>> Support an inter-vm shared memory device that maps a shared-memory
>>>> object as a PCI device in the guest.  This patch also supports
>>>> interrupts between guest by communicating over a unix domain socket.
>>>> This patch applies to the qemu-kvm repository.
>>>>          
>>> No. All new devices should be fully qdev based.
>>>
>>> I suspect you've also ignored a load of coherency issues, especially when
>>> not using KVM. As soon as you have shared memory in more than one host
>>> thread/process you have to worry about memory barriers.
>>>        
>> Shouldn't it be sufficient to require the guest to issue barriers (and
>> to ensure tcg honours the barriers, if someone wants this with tcg)?.
>>      
> In a cross environment that becomes extremely hairy.  For example the x86
> architecture effectively has an implicit write barrier before every store, and
> an implicit read barrier before every load.
>    

Ah yes.  For cross tcg environments you can map the memory using mmio 
callbacks instead of directly, and issue the appropriate barriers there.

-- 
error compiling committee.c: too many arguments to function

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