On Mon, 08 Jun 2015 17:32:27 +0200
Paolo Bonzini <pbonz...@redhat.com> wrote:
>
>
> On 08/06/2015 17:19, Igor Mammedov wrote:
> > +void qemu_ram_unmap_hva(ram_addr_t addr)
> > +{
> > + RAMBlock *block = find_ram_block(addr);
> > +
> > + assert(block);
> > + mmap(block->host, block->used_length, PROT_NONE,
> > + MAP_FIXED | MAP_NORESERVE | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> > +}
> > +
>
> Hmm, this is not good. :( The area at block->host can be in use, for
> example via memory_region_ref/memory_region_unref. This can happen a
> bit after the memory_region_del_subregion. So you can SEGV if you
> simply make a synchronous update. I'm not sure if there is a solution
Yep, that's the problem I haven't found solution to so far,
any ideas hoe to approach this are appreciated.
issue is that we have to re-reserve HVA region first so no other allocation
would claim gap and the only way I found was just to call mmap() on it
which as side effect invalidates MemoryRegion's backing RAM.
> (but thanks for splitting the patches in a way that made the problem
> clear!).
>
> Paolo
