static __read_mostly phys_addr_t xen_grant_frames;
#define GRANT_TABLE_INDEX 0
+#define EXT_REGION_INDEX 1
uint32_t xen_start_flags;
EXPORT_SYMBOL(xen_start_flags);
#endif
}
+#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
+/*
+ * A type-less specific Xen resource which contains extended regions
+ * (unused regions of guest physical address space provided by the hypervisor).
+ */
+static struct resource xen_resource = {
+ .name = "Xen unused space",
+};
+
+int __init arch_xen_unpopulated_init(struct resource **res)
+{
+ struct device_node *np;
+ struct resource *regs, *tmp_res;
+ uint64_t min_gpaddr = -1, max_gpaddr = 0;
+ unsigned int i, nr_reg = 0;
+ int rc;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ if (!acpi_disabled)
+ return -ENODEV;
+
+ np = of_find_compatible_node(NULL, NULL, "xen,xen");
+ if (WARN_ON(!np))
+ return -ENODEV;
+
+ /* Skip region 0 which is reserved for grant table space */
+ while (of_get_address(np, nr_reg + EXT_REGION_INDEX, NULL, NULL))
+ nr_reg++;
+
+ if (!nr_reg) {
+ pr_err("No extended regions are found\n");
+ return -EINVAL;
+ }
+
+ regs = kcalloc(nr_reg, sizeof(*regs), GFP_KERNEL);
+ if (!regs)
+ return -ENOMEM;
+
+ /*
+ * Create resource from extended regions provided by the hypervisor to be
+ * used as unused address space for Xen scratch pages.
+ */
+ for (i = 0; i < nr_reg; i++) {
+ rc = of_address_to_resource(np, i + EXT_REGION_INDEX, ®s[i]);
+ if (rc)
+ goto err;
+
+ if (max_gpaddr < regs[i].end)
+ max_gpaddr = regs[i].end;
+ if (min_gpaddr > regs[i].start)
+ min_gpaddr = regs[i].start;
+ }
+
+ xen_resource.start = min_gpaddr;
+ xen_resource.end = max_gpaddr;
+
+ /*
+ * Mark holes between extended regions as unavailable. The rest of that
+ * address space will be available for the allocation.
+ */
+ for (i = 1; i < nr_reg; i++) {
+ resource_size_t start, end;
+
+ /* There is an overlap between regions */
+ if (regs[i - 1].end + 1 > regs[i].start) {
+ rc = -EINVAL;
+ goto err;
+ }
+
+ /* There is no hole between regions */
+ if (regs[i - 1].end + 1 == regs[i].start)
+ continue;
+
+ start = regs[i - 1].end + 1;
+ end = regs[i].start - 1;
+
+ tmp_res = kzalloc(sizeof(*tmp_res), GFP_KERNEL);
+ if (!tmp_res) {
+ rc = -ENOMEM;
+ goto err;
+ }
+
+ tmp_res->name = "Unavailable space";
+ tmp_res->start = start;
+ tmp_res->end = end;
+
+ rc = insert_resource(&xen_resource, tmp_res);
+ if (rc) {
+ pr_err("Cannot insert resource %pR (%d)\n", tmp_res, rc);
+ kfree(tmp_res);
+ goto err;
+ }
+ }
+
+ *res = &xen_resource;
+
+err:
+ kfree(regs);
+
+ return rc;
+}
+#endif
+
static void __init xen_dt_guest_init(void)
{
struct device_node *xen_node;