Re: [PATCH] softmmu/physmem: Improve guest memory allocation failure error message

[David Hildenbrand]

On 20.08.21 17:52, Philippe Mathieu-Daudé wrote:
> When Linux refuses to overcommit a seriously wild allocation we get:
>
>    $ qemu-system-i386 -m 40000000
>    qemu-system-i386: cannot set up guest memory 'pc.ram': Cannot allocate memory
>
> Slighly improve the error message, displaying the memory size
> requested (in case the user didn't expect unspecified memory size
> unit is in MiB):
>
>    $ qemu-system-i386 -m 40000000
>    qemu-system-i386: Cannot set up 38.1 TiB of guest memory 'pc.ram': Cannot 
> allocate memory
>
> Reported-by: Bin Meng <bmeng.cn@gmail.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   softmmu/physmem.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
> index 2e18947598e..2f300a9e79b 100644
> --- a/softmmu/physmem.c
> +++ b/softmmu/physmem.c
> @@ -1982,8 +1982,10 @@ static void ram_block_add(RAMBlock *new_block, Error 
> **errp)
>                                                     &new_block->mr->align,
>                                                     shared, noreserve);
>               if (!new_block->host) {
> +                g_autofree char *size_s = size_to_str(new_block->max_length);
>                   error_setg_errno(errp, errno,
> -                                 "cannot set up guest memory '%s'",
> +                                 "Cannot set up %s of guest memory '%s'",
> +                                 size_s,
>                                    memory_region_name(new_block->mr));
>                   qemu_mutex_unlock_ramlist();
>                   return;

IIRC, ram blocks might not necessarily be used for guest memory ... or 
is my memory wrong?

--
Thanks,

David / dhildenb