Re: [PATCH v9 09/10] firmware: arm_ffa: Introduce ffa-lend-pool

On Wed, Sep 02, 2026 at 11:47:11AM +0100, Vincent Donnefort wrote:

When memory is lent to the Secure world via FF-A, fatal CPU speculative
reads from Non-Secure can still occur as long as it retains a cacheable
mapping to that memory. Introduce the "arm,ffa-lend-pool"
reserved-memory CMA driver to unmap pages before lending
(ffa_prepare_lend()) and restore them upon reclaim
(ffa_lend_reclaimed()). Devices bind to the pool via the "memory-region"
DT property or via ffa_lend_pool_attach().

  reserved-memory {
      #address-cells = <0x2>;
      #size-cells = <0x2>;
      ranges;

      ffa_lend: ffa-lend-pool {
          compatible = "arm,ffa-lend-pool";

Needs a binding schema...

          reusable;
          ll-map;
          size = <0x0 0x4000000>;
      };
  };

Signed-off-by: Vincent Donnefort <redacted>

[...]

+static int __init ffa_lend_pool_setup(unsigned long node, struct reserved_mem *rmem)
+{
+	struct cma *cma;
+	int ret;
+
+	if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
+	    of_get_flat_dt_prop(node, "no-map", NULL)) {
+		pr_err("FF-A lend pool: node must be 'reusable' and not 'no-map'\n");
+		return -EINVAL;

Your schema should enforce/check this.

[...]

+static const struct reserved_mem_ops ffa_lend_pool_ops = {
+	.node_init	= ffa_lend_pool_setup,
+	.device_init	= ffa_lend_pool_device_init,
+	.device_release = ffa_lend_pool_device_release,
+};
+RESERVEDMEM_OF_DECLARE(ffa_lend_pool, "arm,ffa-lend-pool", &ffa_lend_pool_ops);

Do you need this early? If not, you can create a platform driver for 
"arm,ffa-lend-pool". ramoops is implemented that way for example.

Rob