Re: [Qemu-devel] [RFC PATCH] QEMU may write to system_memory before guest starts

[Peter Maydell]

On Tue, 19 Mar 2019 at 11:03, Dr. David Alan Gilbert
<address@hidden> wrote:
>
> * Peter Maydell (address@hidden) wrote:
> > I didn't think migration distinguished between "main memory"
> > and any other kind of RAMBlock-backed memory ?
>
> In Yury's case there's a distinction between RAMBlock's that are mapped
> with RAM_SHARED (which normally ends up as MAP_SHARED) and all others.
> You can set that for main memory by using -numa to specify a memdev
> that's backed by a file and has the share=on property.
>
> On x86 the ROMs end up as separate RAMBlock's that aren't affected
> by that -numa/share=on - so they don't fight Yury's trick.

You can use the generic loader on x86 to load an ELF file
into RAM if you want, which would I think also trigger this.

thanks
-- PMM