Re: [PATCH v3 12/15] util: vfio-helpers: Implement ram_block_resized()

[Peter Xu]

On Thu, Feb 27, 2020 at 11:12:02AM +0100, David Hildenbrand wrote:
> +static void qemu_vfio_dma_map_resize(QEMUVFIOState *s, void *host,
> +                                     size_t old_size, size_t new_size)
> +{
> +    IOVAMapping *m;
> +    int index = 0;
> +
> +    qemu_mutex_lock(&s->lock);
> +    m = qemu_vfio_find_mapping(s, host, &index);
> +    if (!m) {
> +        return;
> +    }
> +    assert(m->size == old_size);
> +
> +    /* Note: Not atomic - we need a new ioctl for that. */
> +    qemu_vfio_undo_mapping(s, m->iova, m->size);
> +    qemu_vfio_do_mapping(s, host, m->iova, new_size);

Another way to ask my previous question 1 (in the other reply): Can we
simply map/unmap the extra, while keep the shared untouched?

Thanks,

> +
> +    m->size = new_size;
> +    assert(qemu_vfio_verify_mappings(s));
> +
> +    qemu_mutex_unlock(&s->lock);
> +}

-- 
Peter Xu