xen: add helper functions for Xen domain memory management

Add wrapper functions for Xen memory managment hypercall. They can be
used for unprivilaged Zephyr guest initialization and for domain
management, when Zephyr is used as Xen Domain 0.

Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>

drivers/xen/CMakeLists.txt

@@ -4,5 +4,6 @@
 zephyr_sources(hvm.c)
 zephyr_sources(events.c)
 zephyr_sources_ifdef(CONFIG_XEN_GRANT_TABLE gnttab.c)
+zephyr_sources(memory.c)
 
 add_subdirectory_ifdef(CONFIG_XEN_DOM0 dom0)

drivers/xen/memory.c

@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+/*
+ * Copyright (c) 2023 EPAM Systems
+ */
+
+#include <zephyr/arch/arm64/hypercall.h>
+#include <zephyr/xen/generic.h>
+#include <zephyr/xen/public/memory.h>
+#include <zephyr/xen/public/xen.h>
+
+#include <zephyr/kernel.h>
+
+int xendom_add_to_physmap(int domid, unsigned long idx,
+			  unsigned int space, xen_pfn_t gpfn)
+{
+	struct xen_add_to_physmap xatp = {
+		.domid = domid,
+		.idx = idx,
+		.space = space,
+		.gpfn = gpfn,
+	};
+
+	return HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
+}
+
+int xendom_add_to_physmap_batch(int domid, int foreign_domid,
+				unsigned int space, unsigned int size,
+				xen_ulong_t *idxs, xen_pfn_t *gpfns, int *errs)
+{
+	struct xen_add_to_physmap_batch xatpb = {
+		.domid = domid,
+		.u.foreign_domid = foreign_domid,
+		.space = space,
+		.size = size,
+	};
+
+	set_xen_guest_handle(xatpb.gpfns, gpfns);
+	set_xen_guest_handle(xatpb.idxs, idxs);
+	set_xen_guest_handle(xatpb.errs, errs);
+
+	return HYPERVISOR_memory_op(XENMEM_add_to_physmap_batch, &xatpb);
+}
+
+int xendom_remove_from_physmap(int domid, xen_pfn_t gpfn)
+{
+	struct xen_remove_from_physmap xrfp = {
+		.domid = domid,
+		.gpfn = gpfn,
+	};
+
+	return HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrfp);
+}
+
+int xendom_populate_physmap(int domid, unsigned int extent_order,
+			    unsigned int nr_extents, unsigned int mem_flags,
+			    xen_pfn_t *extent_start)
+{
+	struct xen_memory_reservation reservation = {
+		.domid = domid,
+		.extent_order = extent_order,
+		.nr_extents = nr_extents,
+		.mem_flags = mem_flags,
+	};
+
+	set_xen_guest_handle(reservation.extent_start, extent_start);
+
+	return HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
+}

include/zephyr/xen/memory.h

@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+/*
+ * Copyright (c) 2023 EPAM Systems
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/xen/public/memory.h>
+#include <zephyr/xen/public/xen.h>
+
+/**
+ * Add mapping for specified page frame in Xen domain physmap.
+ *
+ * @param domid	domain id, where mapping will be added. For unprivileged should
+ *		be DOMID_SELF.
+ * @param idx	index into space being mapped.
+ * @param space	XENMAPSPACE_* mapping space identifier.
+ * @param gpfn	page frame where the source mapping page should appear.
+ * @return	zero on success, negative errno on error.
+ */
+int xendom_add_to_physmap(int domid, unsigned long idx, unsigned int space,
+			  xen_pfn_t gpfn);
+
+/**
+ * Add mapping for specified set of page frames to Xen domain physmap.
+ *
+ * @param domid		domain id, where mapping will be added. For unprivileged
+ *			should be DOMID_SELF.
+ * @param foreign_domid	for gmfn_foreign - domain id, whose pages being mapped,
+ *			0 for other.
+ * @param space		XENMAPSPACE_* mapping space identifier.
+ * @param size		number of page frames being mapped.
+ * @param idxs		array of indexes into space being mapped.
+ * @param gpfns		array of page frames where the mapping should appear.
+ * @param errs		array of per-index error codes.
+ * @return		zero on success, negative errno on error.
+ */
+int xendom_add_to_physmap_batch(int domid, int foreign_domid,
+				unsigned int space, unsigned int size,
+				xen_ulong_t *idxs, xen_pfn_t *gpfns, int *errs);
+
+/**
+ * Removes page frame from Xen domain physmap.
+ *
+ * @param domid	domain id, whose page is going to be removed. For unprivileged
+ *		should be DOMID_SELF.
+ * @param gpfn	page frame number, that needs to be removed
+ * @return	zero on success, negative errno on error.
+ */
+int xendom_remove_from_physmap(int domid, xen_pfn_t gpfn);
+
+/**
+ * Populate specified Xen domain page frames with memory.
+ *
+ * @param domid		domain id, where mapping will be added. For unprivileged
+ *			should be DOMID_SELF.
+ * @param extent_order	size/alignment of each extent (size is 2^extent_order),
+ *			e.g. 0 for 4K extents, 9 for 2M etc.
+ * @param nr_extents	number of page frames being populated.
+ * @param mem_flags	N/A, should be 0 for Arm.
+ * @param extent_start	page frame bases of extents to populate with memory.
+ * @return		number of populated frames success, negative errno on
+ *			error.
+ */
+int xendom_populate_physmap(int domid, unsigned int extent_order,
+			    unsigned int nr_extents, unsigned int mem_flags,
+			    xen_pfn_t *extent_start);