vpages: Add a simple virtual continuous page allocator

Add a simple virtual page allocator that uses the Zephyr memory mapping
infrastructure to allocate pages from a virtual region and map them
to physical pages.

Due to simplicity, the number of allocations is limited to
CONFIG_SOF_VPAGE_MAX_ALLOCS

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>

Author: lrgirdwo

zephyr/Kconfig

@@ -145,6 +145,19 @@ config SOF_USERSPACE_APPLICATION
 	  Not manually settable. This is effectively a shortcut to replace numerous
 	  checks for (CONFIG_USERSPACE && !CONFIG_SOF_USERSPACE_PROXY)
 
+config SOF_VPAGE_MAX_ALLOCS
+	int "Number of virtual memory page allocations"
+	default 128
+	help
+	  This setting defines the maximum number of virtual memory page
+	  allocations that can be tracked. Each allocation represents a
+	  contiguous block of virtual memory allocated from the virtual memory
+	  region. This API isn't intended for end-user allocations, instead it
+	  should be used by the framework to allocate memory, which is then
+	  used, e.g. to create one or multiple heap allocators in it. Increasing
+	  this number allows for more simultaneous allocations, but also
+	  increases the memory overhead for tracking these allocations.
+
 config ZEPHYR_NATIVE_DRIVERS
 	bool "Use Zephyr native drivers"
 	help

zephyr/include/sof/lib/regions_mm.h

@@ -18,8 +18,9 @@
 #include <zephyr/sys/mem_blocks.h>
 
 /* Attributes for memory regions */
-#define VIRTUAL_REGION_SHARED_HEAP_ATTR 1U	  /*< region dedicated for shared virtual heap */
-#define VIRTUAL_REGION_LLEXT_LIBRARIES_ATTR 2U	  /*< region dedicated for LLEXT libraries */
+#define VIRTUAL_REGION_SHARED_HEAP_ATTR 1U	  /*< region for shared virtual heap */
+#define VIRTUAL_REGION_LLEXT_LIBRARIES_ATTR 2U	  /*< region for LLEXT libraries */
+#define VIRTUAL_REGION_VPAGES_ATTR 3U		  /*< region for virtual page allocator */
 
 /* Dependency on ipc/topology.h created due to memory capability definitions
  * that are defined there

zephyr/include/sof/lib/vpages.h

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright(c) 2025 Intel Corporation.
+
+/* Virtual Page Allocator API */
+#ifndef __SOF_LIB_VPAGE_H__
+#define __SOF_LIB_VPAGE_H__
+
+#include <zephyr/kernel.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Allocate virtual pages
+ * Allocates a specified number of contiguous virtual memory pages by mapping
+ * physical pages.
+ *
+ * @param[in] pages Number of 4kB pages to allocate.
+ *
+ * @return Pointer to the allocated virtual memory region, or NULL on failure.
+ */
+void *vpage_alloc(unsigned int pages);
+
+/**
+ * @brief Free virtual pages
+ * Frees previously allocated virtual memory pages and unmaps them.
+ *
+ * @param[in] ptr Pointer to the memory pages to free.
+ */
+void vpage_free(void *ptr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __SOF_LIB_VPAGE_H__ */