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Re: [Qemu-devel] [PATCH v2 0/6] proposal to make hostmem listener RAM un
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/6] proposal to make hostmem listener RAM unplug safe |
Date: |
Mon, 06 May 2013 08:17:55 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 |
Il 06/05/2013 03:42, liu ping fan ha scritto:
> On Sat, May 4, 2013 at 5:53 PM, Paolo Bonzini <address@hidden> wrote:
>> Il 03/05/2013 04:45, Liu Ping Fan ha scritto:
>>> v1->v2:
>>> 1.split RCU prepared style update and monitor the RAM-Device refcnt into
>>> two patches (patch 2,4)
>>> 2.introduce AddrSpaceMem, which is similar to HostMem, but based on
>>> address space, while
>>> the original HostMem only server system memory address space
>>
>> This looks suspiciously similar to FlatView, doesn't it?
>>
> FlatView is used for all the listeners, including for mmio dispatching,
> which aims to mapping from hwaddr to DeviceState for dispatching service.
> While here, we mapping from hwaddr to hva.
>
>> Perhaps the right thing to do is to add the appropriate locking and
>> RCU-style updating to address_space_update_topology and
>
> RCU implementation is data struct related, and each listener has its
> local table, so I think it is more reasonable to implement them
> separately.
I mentioned address_space_update_topology simply because it is where the
FlatView is replaced.
>> memory_region_find. (And replacing flatview_destroy with ref/unref
>> similar to HostMem in your patch 2). Then just switch dataplane to use
>> memory_region_find...
>>
> In fact, I think, HostMem listener can be an substitute for
> cpu_physical_memory_map(), the main issue can be the migration
> support. But before getting big patches, I hope to have this smaller
> and simpler one.
I think replacing HostMem with FlatView is a smaller patch than these
ones. I'll try to make a prototype.
Paolo
- Re: [Qemu-devel] [PATCH v2 4/6] hostmem: hostmem listener pin RAM-Device by refcnt, (continued)