x86/speculation/mds: Add mitigation control for MDS

[mirror_ubuntu-bionic-kernel.git] / drivers / xen / balloon.c

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index f77e499afdddb02c2d7595459a70b15f3a8c56d5..065f0b607373402a0d4dd7520b9820503390fb0a 100644 (file)
--- 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