Re: [PATCH 1/2] RFC: savevm: check RAM is page_size aligned

[Philippe Mathieu-Daudé]

Hi Marc-André,

On 1/2/20 10:01 PM, Marc-André Lureau wrote:
> Check the host pointer is correctly aligned, otherwise we may fail
> during migration in ram_block_discard_range().
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>   migration/savevm.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index a71b930b91..ab6e02011f 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2910,6 +2910,11 @@ err_drain:
>   
>   void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev)
>   {
> +    RAMBlock *rb = mr->ram_block;
> +    uintptr_t hostaddr = (uintptr_t)qemu_ram_get_host_addr(rb);
> +
> +    assert((hostaddr & (qemu_ram_pagesize(rb) - 1)) == 0);

Can we use the QEMU_PTR_IS_ALIGNED() macro instead?

       assert(QEMU_PTR_IS_ALIGNED(qemu_ram_get_host_addr(rb),
                                  qemu_ram_pagesize(rb)));

>       qemu_ram_set_idstr(mr->ram_block,
>                          memory_region_name(mr), dev);
>       qemu_ram_set_migratable(mr->ram_block);