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Date: Fri, 20 May 2011 12:20:35 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] [RFC v1] Add declarations for hierarchical memory
	region API
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org

On 05/19/2011 10:27 PM, Jan Kiszka wrote:
> On 2011-05-19 16:12, Avi Kivity wrote:
> >  +/* Sets an offset to be added to MemoryRegionOps callbacks. */
> >  +void memory_region_set_offset(MemoryRegion *mr, target_phys_addr_t offset);
>
> Please mark this as a legacy helper, ideally to be removed after the
> complete conversion to this API. During that phase we should try to
> identify those devices which still depend on offset=0 and maybe directly
> fix them.

Okay.

> >  +/* Turn loggging on or off for specified client (display, migration) */
> >  +void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client);
> >  +/* Enable memory coalescing for the region.  MMIO ->write callbacks may be
> >  + * delayed until a non-coalesced MMIO is issued.
> >  + */
> >  +void memory_region_set_coalescing(MemoryRegion *mr);
> >  +/* Enable memory coalescing for a sub-range of the region.  MMIO ->write
> >  + * callbacks may be delayed until a non-coalesced MMIO is issued.
> >  + */
> >  +void memory_region_add_coalescing(MemoryRegion *mr,
> >  +                                  target_phys_addr_t offset,
> >  +                                  target_phys_addr_t size);
>
> Will this be such a common use case that requesting the user to split up
> the region and then use set_coalescing will generate too much boiler
> plate code?

Look at e1000, coalescing ranges have byte granularity.

> >  +/* Disable MMIO coalescing for the region. */
> >  +void memory_region_clear_coalescing(MemoryRegion *mr);
>
> And what about clearing coalescing for sub-ranges?

Clear them all and rebuild.

> Maybe skip
> add_coalescing for the first run and see how far we get.

We get as far as e.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.