Re: [Qemu-devel] [PATCH] cpu_physical_memory_sync_dirty_bitmap: Another alignment fix

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Paolo Bonzini (pbonzini@redhat.com) wrote:
> On 03/01/2018 19:33, Dr. David Alan Gilbert (git) wrote:
> > The optimised version operates on 'longs' dealing with (typically) 64
> > pages at a time, replacing the whole long by a 0 and counting the bits.
> > If the Ramblock is less than 64bits in length that long can contain bits
> > representing two different RAMBlocks, but the code will update the
> > bmap belinging to the 1st RAMBlock only while having updated the total
> > dirty page count for both.
> 
> The patch is obviously correct, but would it make sense also to align
> the RAMBlocks' initial ram_addr_t to a multiple of BITS_PER_LONG <<
> TARGET_PAGE_BITS?

Yes, I can do that as a separate patch.  The alignment starts getting
a little silly - say 4k target page, 64 bits long so aligning a 4k
RAMBlock to 256kb boundary - but I think it's OK.

Dave
P.S. I'd be careful of saying 'obviously correct' given how many small
fixes this function has had recently!

> Thanks,
> 
> Paolo
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK