Re: [PATCH v2 6/7] hostmem: Handle remapping of RAM

[David Hildenbrand <david@redhat.com>]

On 07.11.24 11:21, “William Roche wrote:
> From: David Hildenbrand <david@redhat.com>
> 
> Let's register a RAM block notifier and react on remap notifications.
> Simply re-apply the settings. Warn only when something goes wrong.
> 
> Note: qemu_ram_remap() will not remap when RAM_PREALLOC is set. Could be
> that hostmem is still missing to update that flag ...
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: William Roche <william.roche@oracle.com>
> ---
>   backends/hostmem.c       | 29 +++++++++++++++++++++++++++++
>   include/sysemu/hostmem.h |  1 +
>   2 files changed, 30 insertions(+)
> 
> diff --git a/backends/hostmem.c b/backends/hostmem.c
> index bf85d716e5..fbd8708664 100644
> --- a/backends/hostmem.c
> +++ b/backends/hostmem.c
> @@ -361,11 +361,32 @@ static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
>       backend->prealloc_threads = value;
>   }
>   
> +static void host_memory_backend_ram_remapped(RAMBlockNotifier *n, void *host,
> +                                             size_t offset, size_t size)
> +{
> +    HostMemoryBackend *backend = container_of(n, HostMemoryBackend,
> +                                              ram_notifier);
> +    Error *err = NULL;
> +
> +    if (!host_memory_backend_mr_inited(backend) ||
> +        memory_region_get_ram_ptr(&backend->mr) != host) {
> +        return;
> +    }
> +
> +    host_memory_backend_apply_settings(backend, host + offset, size, &err);
> +    if (err) {
> +        warn_report_err(err);

I wonder if we want to fail hard instead, or have a way to tell the 
notifier that something wen wrong.

-- 
Cheers,

David / dhildenb