Revert "xen/balloon: Mark unallocated host memory as UNUSABLE"
authorIgor Druzhinin <igor.druzhinin@citrix.com>
Tue, 27 Nov 2018 20:58:21 +0000 (20:58 +0000)
committerJuergen Gross <jgross@suse.com>
Thu, 29 Nov 2018 16:53:31 +0000 (17:53 +0100)
This reverts commit b3cf8528bb21febb650a7ecbf080d0647be40b9f.

That commit unintentionally broke Xen balloon memory hotplug with
"hotplug_unpopulated" set to 1. As long as "System RAM" resource
got assigned under a new "Unusable memory" resource in IO/Mem tree
any attempt to online this memory would fail due to general kernel
restrictions on having "System RAM" resources as 1st level only.

The original issue that commit has tried to workaround fa564ad96366
("x86/PCI: Enable a 64bit BAR on AMD Family 15h (Models 00-1f, 30-3f,
60-7f)") also got amended by the following 03a551734 ("x86/PCI: Move
and shrink AMD 64-bit window to avoid conflict") which made the
original fix to Xen ballooning unnecessary.

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
arch/x86/xen/enlighten.c
arch/x86/xen/setup.c
drivers/xen/balloon.c
include/xen/balloon.h

index 67b2f31a1265f3d6db430974428f8cbdef56150d..aa1cc483bd2a228c6b1f872314516b14720ef847 100644 (file)
@@ -10,7 +10,6 @@
 #include <xen/xen.h>
 #include <xen/features.h>
 #include <xen/page.h>
-#include <xen/interface/memory.h>
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
@@ -346,80 +345,3 @@ void xen_arch_unregister_cpu(int num)
 }
 EXPORT_SYMBOL(xen_arch_unregister_cpu);
 #endif
-
-#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
-void __init arch_xen_balloon_init(struct resource *hostmem_resource)
-{
-       struct xen_memory_map memmap;
-       int rc;
-       unsigned int i, last_guest_ram;
-       phys_addr_t max_addr = PFN_PHYS(max_pfn);
-       struct e820_table *xen_e820_table;
-       const struct e820_entry *entry;
-       struct resource *res;
-
-       if (!xen_initial_domain())
-               return;
-
-       xen_e820_table = kmalloc(sizeof(*xen_e820_table), GFP_KERNEL);
-       if (!xen_e820_table)
-               return;
-
-       memmap.nr_entries = ARRAY_SIZE(xen_e820_table->entries);
-       set_xen_guest_handle(memmap.buffer, xen_e820_table->entries);
-       rc = HYPERVISOR_memory_op(XENMEM_machine_memory_map, &memmap);
-       if (rc) {
-               pr_warn("%s: Can't read host e820 (%d)\n", __func__, rc);
-               goto out;
-       }
-
-       last_guest_ram = 0;
-       for (i = 0; i < memmap.nr_entries; i++) {
-               if (xen_e820_table->entries[i].addr >= max_addr)
-                       break;
-               if (xen_e820_table->entries[i].type == E820_TYPE_RAM)
-                       last_guest_ram = i;
-       }
-
-       entry = &xen_e820_table->entries[last_guest_ram];
-       if (max_addr >= entry->addr + entry->size)
-               goto out; /* No unallocated host RAM. */
-
-       hostmem_resource->start = max_addr;
-       hostmem_resource->end = entry->addr + entry->size;
-
-       /*
-        * Mark non-RAM regions between the end of dom0 RAM and end of host RAM
-        * as unavailable. The rest of that region can be used for hotplug-based
-        * ballooning.
-        */
-       for (; i < memmap.nr_entries; i++) {
-               entry = &xen_e820_table->entries[i];
-
-               if (entry->type == E820_TYPE_RAM)
-                       continue;
-
-               if (entry->addr >= hostmem_resource->end)
-                       break;
-
-               res = kzalloc(sizeof(*res), GFP_KERNEL);
-               if (!res)
-                       goto out;
-
-               res->name = "Unavailable host RAM";
-               res->start = entry->addr;
-               res->end = (entry->addr + entry->size < hostmem_resource->end) ?
-                           entry->addr + entry->size : hostmem_resource->end;
-               rc = insert_resource(hostmem_resource, res);
-               if (rc) {
-                       pr_warn("%s: Can't insert [%llx - %llx) (%d)\n",
-                               __func__, res->start, res->end, rc);
-                       kfree(res);
-                       goto  out;
-               }
-       }
-
- out:
-       kfree(xen_e820_table);
-}
-#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
index 1163e33121fb39af673743b0eda9de5007629c63..075ed47993bbf5c1bf9b760511268613c035d8c1 100644 (file)
@@ -808,6 +808,7 @@ char * __init xen_memory_setup(void)
        addr = xen_e820_table.entries[0].addr;
        size = xen_e820_table.entries[0].size;
        while (i < xen_e820_table.nr_entries) {
+               bool discard = false;
 
                chunk_size = size;
                type = xen_e820_table.entries[i].type;
@@ -823,10 +824,11 @@ char * __init xen_memory_setup(void)
                                xen_add_extra_mem(pfn_s, n_pfns);
                                xen_max_p2m_pfn = pfn_s + n_pfns;
                        } else
-                               type = E820_TYPE_UNUSABLE;
+                               discard = true;
                }
 
-               xen_align_and_add_e820_region(addr, chunk_size, type);
+               if (!discard)
+                       xen_align_and_add_e820_region(addr, chunk_size, type);
 
                addr += chunk_size;
                size -= chunk_size;
index e12bb256036fbb0d56ee2523ec60b929f57340d5..7ab6caef599c59c57e1de6e25b03a073652472c7 100644 (file)
@@ -251,25 +251,10 @@ 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, *res_hostmem;
-       int ret = -ENOMEM;
+       struct resource *res;
+       int ret;
 
        res = kzalloc(sizeof(*res), GFP_KERNEL);
        if (!res)
@@ -278,42 +263,13 @@ static struct resource *additional_memory_resource(phys_addr_t size)
        res->name = "System RAM";
        res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 
-       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;
-               }
+       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
@@ -325,7 +281,6 @@ 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;
                }
        }
@@ -747,8 +702,6 @@ 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
index 61f410fd74e4cf4180f7ad5ffa1d996cc1528c91..4914b93a23f2bdeb066a4048d7ab749456ae3fe3 100644 (file)
@@ -44,8 +44,3 @@ static inline void xen_balloon_init(void)
 {
 }
 #endif
-
-#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
-struct resource;
-void arch_xen_balloon_init(struct resource *hostmem_resource);
-#endif