Re: [ANNOUNCE] kvm-46 release

Jun Koi
2007-10-10T09:04:03Z

On 10/10/07, Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> wrote:
> Jun Koi wrote:
> > Hi,
> >
> > On 10/10/07, Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> wrote:
> >
> >> We've now switched to allocating guest memory in userspace rather than
> >> in the kernel. This is important if you have a mainframe, but also if
> >> you want to share memory between guests and implement nice features like
> >> swapping.
> >>
> >
> > This is interesting! But how can we do that now? (share memory between guests)
> >
> >
>
> It's not exposed by qemu, but you can now mmap() some file (or use SysV
> shared memory) and use that as guest memory.
>

OK, lets say we have 2 guest VMs share a memory, like mmap() a tmpfs
file (which is actually in memory). Now one writes to the memory
(shared file). Can we guarantee that the memory immediately updated,
so other will see the change immediately? Or the data might be cached
for a while, befere being flushed to the shared memory?

Thanks,
Jun