Merge tag 'ffa-fix-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/fixes

Arm FF-A fix for v6.6

It has been reported that the driver sets the memory region attributes
for MEM_LEND operation when the specification clearly states not to. The
fix here addresses the issue by ensuring the memory region attributes are
cleared for the memory lending operation.

* tag 'ffa-fix-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_ffa: Don't set the memory region attributes for MEM_LEND

Link: https://lore.kernel.org/r/20230927121555.158619-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Author: arndb

drivers/firmware/arm_ffa/driver.c

@@ -397,6 +397,19 @@ static u32 ffa_get_num_pages_sg(struct scatterlist *sg)
 	return num_pages;
 }
 
+static u8 ffa_memory_attributes_get(u32 func_id)
+{
+	/*
+	 * For the memory lend or donate operation, if the receiver is a PE or
+	 * a proxy endpoint, the owner/sender must not specify the attributes
+	 */
+	if (func_id == FFA_FN_NATIVE(MEM_LEND) ||
+	    func_id == FFA_MEM_LEND)
+		return 0;
+
+	return FFA_MEM_NORMAL | FFA_MEM_WRITE_BACK | FFA_MEM_INNER_SHAREABLE;
+}
+
 static int
 ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
 		       struct ffa_mem_ops_args *args)
@@ -413,8 +426,7 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
 	mem_region->tag = args->tag;
 	mem_region->flags = args->flags;
 	mem_region->sender_id = drv_info->vm_id;
-	mem_region->attributes = FFA_MEM_NORMAL | FFA_MEM_WRITE_BACK |
-				 FFA_MEM_INNER_SHAREABLE;
+	mem_region->attributes = ffa_memory_attributes_get(func_id);
 	ep_mem_access = &mem_region->ep_mem_access[0];
 
 	for (idx = 0; idx < args->nattrs; idx++, ep_mem_access++) {