Re: [QEMU][PATCH v1 5/7] memory: add MemoryRegion map and unmap callbacks

[Juergen Gross]

On 10.10.23 02:17, Stefano Stabellini wrote:
> On Thu, 5 Oct 2023, Vikram Garhwal wrote:
> > From: Juergen Gross <jgross@suse.com>
> >
> > In order to support mapping and unmapping guest memory dynamically to
> > and from qemu during address_space_[un]map() operations add the map()
> > and unmap() callbacks to MemoryRegionOps.
> >
> > Those will be used e.g. for Xen grant mappings when performing guest
> > I/Os.
> >
> > Signed-off-by: Juergen Gross <jgross@suse.com>
> > Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
>
> Can't we just use the existing Xen hooks in qemu_ram_ptr_length and
> xen_invalidate_map_cache_entry? Do we really need new ones?

I tried your idea first and it didn't work out.

The existing hooks are invoked not only when explicitly [un]mapping memory
regions, but in some other cases, too. Have a look for qemu_ram_ptr_length()
call in flatview_write_continue().


Juergen

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