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-rw-r--r--drivers/xen/balloon.c65
1 files changed, 56 insertions, 9 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index f77e499afddd..065f0b607373 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -257,10 +257,25 @@ static void release_memory_resource(struct resource *resource)
kfree(resource);
}
+/*
+ * Host memory not allocated to dom0. We can use this range for hotplug-based
+ * ballooning.
+ *
+ * It's a type-less resource. Setting IORESOURCE_MEM will make resource
+ * management algorithms (arch_remove_reservations()) look into guest e820,
+ * which we don't want.
+ */
+static struct resource hostmem_resource = {
+ .name = "Host RAM",
+};
+
+void __attribute__((weak)) __init arch_xen_balloon_init(struct resource *res)
+{}
+
static struct resource *additional_memory_resource(phys_addr_t size)
{
- struct resource *res;
- int ret;
+ struct resource *res, *res_hostmem;
+ int ret = -ENOMEM;
res = kzalloc(sizeof(*res), GFP_KERNEL);
if (!res)
@@ -269,13 +284,42 @@ static struct resource *additional_memory_resource(phys_addr_t size)
res->name = "System RAM";
res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
- ret = allocate_resource(&iomem_resource, res,
- size, 0, -1,
- PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
- if (ret < 0) {
- pr_err("Cannot allocate new System RAM resource\n");
- kfree(res);
- return NULL;
+ res_hostmem = kzalloc(sizeof(*res), GFP_KERNEL);
+ if (res_hostmem) {
+ /* Try to grab a range from hostmem */
+ res_hostmem->name = "Host memory";
+ ret = allocate_resource(&hostmem_resource, res_hostmem,
+ size, 0, -1,
+ PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
+ }
+
+ if (!ret) {
+ /*
+ * Insert this resource into iomem. Because hostmem_resource
+ * tracks portion of guest e820 marked as UNUSABLE noone else
+ * should try to use it.
+ */
+ res->start = res_hostmem->start;
+ res->end = res_hostmem->end;
+ ret = insert_resource(&iomem_resource, res);
+ if (ret < 0) {
+ pr_err("Can't insert iomem_resource [%llx - %llx]\n",
+ res->start, res->end);
+ release_memory_resource(res_hostmem);
+ res_hostmem = NULL;
+ res->start = res->end = 0;
+ }
+ }
+
+ if (ret) {
+ ret = allocate_resource(&iomem_resource, res,
+ size, 0, -1,
+ PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
+ if (ret < 0) {
+ pr_err("Cannot allocate new System RAM resource\n");
+ kfree(res);
+ return NULL;
+ }
}
#ifdef CONFIG_SPARSEMEM
@@ -287,6 +331,7 @@ static struct resource *additional_memory_resource(phys_addr_t size)
pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n",
pfn, limit);
release_memory_resource(res);
+ release_memory_resource(res_hostmem);
return NULL;
}
}
@@ -765,6 +810,8 @@ static int __init balloon_init(void)
set_online_page_callback(&xen_online_page);
register_memory_notifier(&xen_memory_nb);
register_sysctl_table(xen_root);
+
+ arch_xen_balloon_init(&hostmem_resource);
#endif
#ifdef CONFIG_XEN_PV
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