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Subject: Re: [Qemu-devel] [PATCH v7 0/7] push mmio dispatch out of big lock
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To: qemu-devel <qemu-devel@nongnu.org>, Jan Kiszka <jan.kiszka@siemens.com>, Liu Ping Fan <qemulist@gmail.com>

Il 03/05/2013 10:04, Jan Kiszka ha scritto:
> We can't change the semantics of opaque as long as old_mmio / old_portio
> are around. But we need a flag anyway to indicate if a region is
> depending on BQL or not. Adding a separate "Object *owner" to
> MemoryRegion can serve both purposes. Then we define something like
> 
> void memory_region_set_local_locking(MemoryRegion *mr,
>                                      bool local_locking,
>                                      Object *owner);
> 
> to control the property (if local_locking is true, owner must be
> non-NULL, of course). That's quite similar to my old prototype here that
> had memory_region_set/clear_global_locking.

I think setting the owner can be done separately from enabling local
lock.  For example, memory_region_find could also have a variant that
adds a ref to the owner.  It would be very similar to what Ping Fan is
doing in the virtio-dataplane's HostMem data structure.

Paolo