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authorLinus Torvalds <torvalds@linux-foundation.org>2015-04-02 13:53:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-02 13:53:53 -0700
commitb0838b150160f90be0903a38a2ce11d764962752 (patch)
tree39c71db2c10e4115c7755142b0444191f32b9c07
parent1d514333da19410751c195cc715f9dbe1bb4b08f (diff)
parent3c56b3a12ce52f361468cbdd2f79b2f3b8da0ea6 (diff)
Merge tag 'stable/for-linus-4.0-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen regression fixes from David Vrabel: "Fix two regressions in the balloon driver's use of memory hotplug when used in a PV guest" * tag 'stable/for-linus-4.0-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/balloon: before adding hotplugged memory, set frames to invalid x86/xen: prepare p2m list for memory hotplug
-rw-r--r--arch/x86/xen/p2m.c10
-rw-r--r--drivers/xen/Kconfig17
-rw-r--r--drivers/xen/balloon.c23
3 files changed, 49 insertions, 1 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 9f93af56a5fc..b47124d4cd67 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -91,6 +91,12 @@ EXPORT_SYMBOL_GPL(xen_p2m_size);
unsigned long xen_max_p2m_pfn __read_mostly;
EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
+#define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
+#else
+#define P2M_LIMIT 0
+#endif
+
static DEFINE_SPINLOCK(p2m_update_lock);
static unsigned long *p2m_mid_missing_mfn;
@@ -385,9 +391,11 @@ static void __init xen_rebuild_p2m_list(unsigned long *p2m)
void __init xen_vmalloc_p2m_tree(void)
{
static struct vm_struct vm;
+ unsigned long p2m_limit;
+ p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE;
vm.flags = VM_ALLOC;
- vm.size = ALIGN(sizeof(unsigned long) * xen_max_p2m_pfn,
+ vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit),
PMD_SIZE * PMDS_PER_MID_PAGE);
vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index b812462083fc..94d96809e686 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -55,6 +55,23 @@ config XEN_BALLOON_MEMORY_HOTPLUG
In that case step 3 should be omitted.
+config XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
+ int "Hotplugged memory limit (in GiB) for a PV guest"
+ default 512 if X86_64
+ default 4 if X86_32
+ range 0 64 if X86_32
+ depends on XEN_HAVE_PVMMU
+ depends on XEN_BALLOON_MEMORY_HOTPLUG
+ help
+ Maxmium amount of memory (in GiB) that a PV guest can be
+ expanded to when using memory hotplug.
+
+ A PV guest can have more memory than this limit if is
+ started with a larger maximum.
+
+ This value is used to allocate enough space in internal
+ tables needed for physical memory administration.
+
config XEN_SCRUB_PAGES
bool "Scrub pages before returning them to system"
depends on XEN_BALLOON
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 0b52d92cb2e5..fd933695f232 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -229,6 +229,29 @@ static enum bp_state reserve_additional_memory(long credit)
balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION);
nid = memory_add_physaddr_to_nid(hotplug_start_paddr);
+#ifdef CONFIG_XEN_HAVE_PVMMU
+ /*
+ * add_memory() will build page tables for the new memory so
+ * the p2m must contain invalid entries so the correct
+ * non-present PTEs will be written.
+ *
+ * If a failure occurs, the original (identity) p2m entries
+ * are not restored since this region is now known not to
+ * conflict with any devices.
+ */
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ unsigned long pfn, i;
+
+ pfn = PFN_DOWN(hotplug_start_paddr);
+ for (i = 0; i < balloon_hotplug; i++) {
+ if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
+ pr_warn("set_phys_to_machine() failed, no memory added\n");
+ return BP_ECANCELED;
+ }
+ }
+ }
+#endif
+
rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT);
if (rc) {