Re: shared memory and event channel

[tgh <wwwwww4187@sina.com.cn>]

hi
  I read the code of eventchannel,and I am confused by the viarable 
named as"consumer_is_xen"in the evtchn struct, what is the function of 
consumer_is_xen? and does dom use eventchannel to communicate with 
hypervisor? why not the hypercall? and in which condition is 
eventchannel used in this way,that is ,the dom issues an event to 
hypervisor or xen,and xen is a consumer?

Thanks in advance




Mark Williamson 写道:
>>    For each domUs there is unique shared memory(2-way circular queue) and
>> event-channel(one shared memory and event-channel per domU) or there is
>> only one shared memory and interdomain event-channel(for every DomU)?
>>     
>
> Each domain has a separate shared memory page and event channel.  Actually, in 
> general, there are multiple shared memory areas and event channels per domU.
>
> Each virtual device (e.g. virtual network interface) may require its own 
> separate shared memory page and event channel to talk to the backend.  So if 
> you have a domain with two vifs it'll need two shared memory pages and two 
> event channels.
>
> The block driver will also want a memory page and event channel for each 
> virtual block device.
>
> And so on.
>
> Hope this helps,
>
> Cheers,
> Mark
>
>