On 05.02.2026 02:36, [email protected] wrote:
> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -463,20 +463,34 @@ static void cf_check conring_dump_keyhandler(unsigned
> char key)
> void __init console_init_ring(void)
> {
> char *ring;
> - unsigned int start, size, chunk, order, memflags;
> + unsigned int start, size, chunk;
> unsigned long flags;
>
> if ( !opt_conring_size )
> return;
>
> - order = get_order_from_bytes(max(opt_conring_size, conring_size));
> - memflags = MEMF_bits(crashinfo_maxaddr_bits);
> - while ( (ring = alloc_xenheap_pages(order, memflags)) == NULL )
> + opt_conring_size = max(opt_conring_size, conring_size);
> + size = ROUNDDOWN(opt_conring_size, PAGE_SIZE);
> + if ( size != opt_conring_size )
> {
> - BUG_ON(order == 0);
> - order--;
> + opt_conring_size = size;
> + printk(XENLOG_WARNING "Rounding down console ring size to multiple
> of %lu KiB.\n",
> + PAGE_SIZE >> 10);
> }
> - opt_conring_size = PAGE_SIZE << order;
I've spotted this removal only while looking at patch 6: How does this
work? We require conring_size to be a power of 2, or else masking by
(conring_size - 1) isn't a valid thing to do. You even touch
CONRING_IDX_MASK() twice in this series, so you really should have
noticed.
> + if ( opt_conring_size >= GB(2) )
> + {
> + opt_conring_size = GB(2);
> + printk(XENLOG_WARNING "Limiting user-configured console ring
> size.\n");
> + }
> + else if ( opt_conring_size < _CONRING_SIZE )
> + {
> + opt_conring_size = _CONRING_SIZE;
> + printk(XENLOG_WARNING "Using compile-time console ring size.\n");
> + }
> +
> + /* Contiguous buffer; does not need to be naturally aligned. */
> + ring = xmalloc_bytes(opt_conring_size);
> + BUG_ON(ring == NULL);
>
> nrspin_lock_irqsave(&console_lock, flags);
>
