11 files changed, 197 insertions, 83 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index dc6ef9a2c649..e25419817791 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1905,6 +1905,7 @@ config XEN
         depends on !GENERIC_ATOMIC64
         select ARM_PSCI
         select SWIOTLB_XEN
+        select ARCH_DMA_ADDR_T_64BIT
         help
           Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
 
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 2162172c0ddc..b96723e258a0 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -23,6 +23,7 @@
 #include <linux/of_address.h>
 #include <linux/cpuidle.h>
 #include <linux/cpufreq.h>
+#include <linux/cpu.h>
 
 #include <linux/mm.h>
 
@@ -154,7 +155,7 @@ int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
 }
 EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
 
-static void __init xen_percpu_init(void *unused)
+static void xen_percpu_init(void)
 {
         struct vcpu_register_vcpu_info info;
         struct vcpu_info *vcpup;
@@ -193,6 +194,31 @@ static void xen_power_off(void)
                 BUG();
 }
 
+static int xen_cpu_notification(struct notifier_block *self,
+                                unsigned long action,
+                                void *hcpu)
+{
+        switch (action) {
+        case CPU_STARTING:
+                xen_percpu_init();
+                break;
+        default:
+                break;
+        }
+
+        return NOTIFY_OK;
+}
+
+static struct notifier_block xen_cpu_notifier = {
+        .notifier_call = xen_cpu_notification,
+};
+
+static irqreturn_t xen_arm_callback(int irq, void *arg)
+{
+        xen_hvm_evtchn_do_upcall();
+        return IRQ_HANDLED;
+}
+
 /*
  * see Documentation/devicetree/bindings/arm/xen.txt for the
  * documentation of the Xen Device Tree format.
@@ -208,7 +234,7 @@ static int __init xen_guest_init(void)
         const char *version = NULL;
         const char *xen_prefix = "xen,xen-";
         struct resource res;
-        unsigned long grant_frames;
+        phys_addr_t grant_frames;
 
         node = of_find_compatible_node(NULL, NULL, "xen,xen");
         if (!node) {
@@ -227,8 +253,12 @@ static int __init xen_guest_init(void)
                 return 0;
         grant_frames = res.start;
         xen_events_irq = irq_of_parse_and_map(node, 0);
-        pr_info("Xen %s support found, events_irq=%d gnttab_frame_pfn=%lx\n",
-                        version, xen_events_irq, (grant_frames >> PAGE_SHIFT));
+        pr_info("Xen %s support found, events_irq=%d gnttab_frame=%pa\n",
+                        version, xen_events_irq, &grant_frames);
+
+        if (xen_events_irq < 0)
+                return -ENODEV;
+
         xen_domain_type = XEN_HVM_DOMAIN;
 
         xen_setup_features();
@@ -281,9 +311,21 @@ static int __init xen_guest_init(void)
         disable_cpuidle();
         disable_cpufreq();
 
+        xen_init_IRQ();
+
+        if (request_percpu_irq(xen_events_irq, xen_arm_callback,
+                               "events", &xen_vcpu)) {
+                pr_err("Error request IRQ %d\n", xen_events_irq);
+                return -EINVAL;
+        }
+
+        xen_percpu_init();
+
+        register_cpu_notifier(&xen_cpu_notifier);
+
         return 0;
 }
-core_initcall(xen_guest_init);
+early_initcall(xen_guest_init);
 
 static int __init xen_pm_init(void)
 {
@@ -297,31 +339,6 @@ static int __init xen_pm_init(void)
 }
 late_initcall(xen_pm_init);
 
-static irqreturn_t xen_arm_callback(int irq, void *arg)
-{
-        xen_hvm_evtchn_do_upcall();
-        return IRQ_HANDLED;
-}
-
-static int __init xen_init_events(void)
-{
-        if (!xen_domain() || xen_events_irq < 0)
-                return -ENODEV;
-
-        xen_init_IRQ();
-
-        if (request_percpu_irq(xen_events_irq, xen_arm_callback,
-                        "events", &xen_vcpu)) {
-                pr_err("Error requesting IRQ %d\n", xen_events_irq);
-                return -EINVAL;
-        }
-
-        on_each_cpu(xen_percpu_init, NULL, 0);
-
-        return 0;
-}
-postcore_initcall(xen_init_events);
-
 /* In the hypervisor.S file. */
 EXPORT_SYMBOL_GPL(HYPERVISOR_event_channel_op);
 EXPORT_SYMBOL_GPL(HYPERVISOR_grant_table_op);
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 3e276eb23d1b..787e1bb5aafc 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -52,7 +52,8 @@ extern unsigned long set_phys_range_identity(unsigned long pfn_s,
 extern int m2p_add_override(unsigned long mfn, struct page *page,
                             struct gnttab_map_grant_ref *kmap_op);
 extern int m2p_remove_override(struct page *page,
-                                struct gnttab_map_grant_ref *kmap_op);
+                               struct gnttab_map_grant_ref *kmap_op,
+                               unsigned long mfn);
 extern struct page *m2p_find_override(unsigned long mfn);
 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
 
@@ -121,7 +122,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
                 pfn = m2p_find_override_pfn(mfn, ~0);
         }
 
-        /* 
+        /*
          * pfn is ~0 if there are no entries in the m2p for mfn or if the
          * entry doesn't map back to the mfn and m2p_override doesn't have a
          * valid entry for it.
diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
index 103c93f874b2..c98583588580 100644
--- a/arch/x86/xen/grant-table.c
+++ b/arch/x86/xen/grant-table.c
@@ -162,14 +162,15 @@ static int __init xlated_setup_gnttab_pages(void)
         rc = arch_gnttab_map_shared(pfns, nr_grant_frames, nr_grant_frames,
                                     &xen_auto_xlat_grant_frames.vaddr);
 
-        kfree(pages);
         if (rc) {
                 pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__,
                         nr_grant_frames, rc);
                 free_xenballooned_pages(nr_grant_frames, pages);
+                kfree(pages);
                 kfree(pfns);
                 return rc;
         }
+        kfree(pages);
 
         xen_auto_xlat_grant_frames.pfn = pfns;
         xen_auto_xlat_grant_frames.count = nr_grant_frames;
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 696c694986d0..8009acbe41e4 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -899,13 +899,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
                                         "m2p_add_override: pfn %lx not mapped", pfn))
                         return -EINVAL;
         }
-        WARN_ON(PagePrivate(page));
-        SetPagePrivate(page);
-        set_page_private(page, mfn);
-        page->index = pfn_to_mfn(pfn);
-
-        if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
-                return -ENOMEM;
 
         if (kmap_op != NULL) {
                 if (!PageHighMem(page)) {
@@ -944,19 +937,16 @@ int m2p_add_override(unsigned long mfn, struct page *page,
 }
 EXPORT_SYMBOL_GPL(m2p_add_override);
 int m2p_remove_override(struct page *page,
-                struct gnttab_map_grant_ref *kmap_op)
+                        struct gnttab_map_grant_ref *kmap_op,
+                        unsigned long mfn)
 {
         unsigned long flags;
-        unsigned long mfn;
         unsigned long pfn;
         unsigned long uninitialized_var(address);
         unsigned level;
         pte_t *ptep = NULL;
 
         pfn = page_to_pfn(page);
-        mfn = get_phys_to_machine(pfn);
-        if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
-                return -EINVAL;
 
         if (!PageHighMem(page)) {
                 address = (unsigned long)__va(pfn << PAGE_SHIFT);
@@ -970,10 +960,7 @@ int m2p_remove_override(struct page *page,
         spin_lock_irqsave(&m2p_override_lock, flags);
         list_del(&page->lru);
         spin_unlock_irqrestore(&m2p_override_lock, flags);
-        WARN_ON(!PagePrivate(page));
-        ClearPagePrivate(page);
 
-        set_phys_to_machine(pfn, page->index);
         if (kmap_op != NULL) {
                 if (!PageHighMem(page)) {
                         struct multicall_space mcs;
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 4b97b86da926..da18046d0e07 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -285,8 +285,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
 
                 if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
                         !rb_next(&persistent_gnt->node)) {
-                        ret = gnttab_unmap_refs(unmap, NULL, pages,
-                                segs_to_unmap);
+                        ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
                         BUG_ON(ret);
                         put_free_pages(blkif, pages, segs_to_unmap);
                         segs_to_unmap = 0;
@@ -321,8 +320,7 @@ static void unmap_purged_grants(struct work_struct *work)
                 pages[segs_to_unmap] = persistent_gnt->page;
 
                 if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
-                        ret = gnttab_unmap_refs(unmap, NULL, pages,
-                                segs_to_unmap);
+                        ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
                         BUG_ON(ret);
                         put_free_pages(blkif, pages, segs_to_unmap);
                         segs_to_unmap = 0;
@@ -330,7 +328,7 @@ static void unmap_purged_grants(struct work_struct *work)
                 kfree(persistent_gnt);
         }
         if (segs_to_unmap > 0) {
-                ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap);
+                ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
                 BUG_ON(ret);
                 put_free_pages(blkif, pages, segs_to_unmap);
         }
@@ -670,15 +668,14 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif,
                                     GNTMAP_host_map, pages[i]->handle);
                 pages[i]->handle = BLKBACK_INVALID_HANDLE;
                 if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
-                        ret = gnttab_unmap_refs(unmap, NULL, unmap_pages,
-                                                invcount);
+                        ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
                         BUG_ON(ret);
                         put_free_pages(blkif, unmap_pages, invcount);
                         invcount = 0;
                 }
         }
         if (invcount) {
-                ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
+                ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
                 BUG_ON(ret);
                 put_free_pages(blkif, unmap_pages, invcount);
         }
@@ -740,7 +737,7 @@ again:
         }
 
         if (segs_to_map) {
-                ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
+                ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map);
                 BUG_ON(ret);
         }
 
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 073b4a19a8b0..34a2704fbc88 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -284,8 +284,10 @@ static int map_grant_pages(struct grant_map *map)
         }
 
         pr_debug("map %d+%d\n", map->index, map->count);
-        err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
-                        map->pages, map->count);
+        err = gnttab_map_refs_userspace(map->map_ops,
+                                        use_ptemod ? map->kmap_ops : NULL,
+                                        map->pages,
+                                        map->count);
         if (err)
                 return err;
 
@@ -315,9 +317,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
                 }
         }
 
-        err = gnttab_unmap_refs(map->unmap_ops + offset,
-                        use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
-                        pages);
+        err = gnttab_unmap_refs_userspace(map->unmap_ops + offset,
+                                          use_ptemod ? map->kmap_ops + offset : NULL,
+                                          map->pages + offset,
+                                          pages);
         if (err)
                 return err;
 
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 1ce1c40331f3..8ee13e2e45e2 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -837,7 +837,7 @@ unsigned int gnttab_max_grant_frames(void)
 }
 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 
-int gnttab_setup_auto_xlat_frames(unsigned long addr)
+int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
 {
         xen_pfn_t *pfn;
         unsigned int max_nr_gframes = __max_nr_grant_frames();
@@ -849,8 +849,8 @@ int gnttab_setup_auto_xlat_frames(unsigned long addr)
 
         vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes);
         if (vaddr == NULL) {
-                pr_warn("Failed to ioremap gnttab share frames (addr=0x%08lx)!\n",
-                        addr);
+                pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
+                        &addr);
                 return -ENOMEM;
         }
         pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
@@ -928,15 +928,17 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
 }
 EXPORT_SYMBOL_GPL(gnttab_batch_copy);
 
-int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
                     struct gnttab_map_grant_ref *kmap_ops,
-                    struct page **pages, unsigned int count)
+                    struct page **pages, unsigned int count,
+                    bool m2p_override)
 {
         int i, ret;
         bool lazy = false;
         pte_t *pte;
-        unsigned long mfn;
+        unsigned long mfn, pfn;
 
+        BUG_ON(kmap_ops && !m2p_override);
         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
         if (ret)
                 return ret;
@@ -955,10 +957,12 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
                         set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
                                         map_ops[i].dev_bus_addr >> PAGE_SHIFT);
                 }
-                return ret;
+                return 0;
         }
 
-        if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
+        if (m2p_override &&
+            !in_interrupt() &&
+            paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
                 arch_enter_lazy_mmu_mode();
                 lazy = true;
         }
@@ -975,8 +979,20 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
                 } else {
                         mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
                 }
-                ret = m2p_add_override(mfn, pages[i], kmap_ops ?
-                                       &kmap_ops[i] : NULL);
+                pfn = page_to_pfn(pages[i]);
+
+                WARN_ON(PagePrivate(pages[i]));
+                SetPagePrivate(pages[i]);
+                set_page_private(pages[i], mfn);
+
+                pages[i]->index = pfn_to_mfn(pfn);
+                if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
+                        ret = -ENOMEM;
+                        goto out;
+                }
+                if (m2p_override)
+                        ret = m2p_add_override(mfn, pages[i], kmap_ops ?
+                                               &kmap_ops[i] : NULL);
                 if (ret)
                         goto out;
         }
@@ -987,15 +1003,32 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 
         return ret;
 }
+
+int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+                    struct page **pages, unsigned int count)
+{
+        return __gnttab_map_refs(map_ops, NULL, pages, count, false);
+}
 EXPORT_SYMBOL_GPL(gnttab_map_refs);
 
-int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
+int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
+                              struct gnttab_map_grant_ref *kmap_ops,
+                              struct page **pages, unsigned int count)
+{
+        return __gnttab_map_refs(map_ops, kmap_ops, pages, count, true);
+}
+EXPORT_SYMBOL_GPL(gnttab_map_refs_userspace);
+
+int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
                       struct gnttab_map_grant_ref *kmap_ops,
-                      struct page **pages, unsigned int count)
+                      struct page **pages, unsigned int count,
+                      bool m2p_override)
 {
         int i, ret;
         bool lazy = false;
+        unsigned long pfn, mfn;
 
+        BUG_ON(kmap_ops && !m2p_override);
         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
         if (ret)
                 return ret;
@@ -1006,17 +1039,33 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
                         set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
                                         INVALID_P2M_ENTRY);
                 }
-                return ret;
+                return 0;
         }
 
-        if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
+        if (m2p_override &&
+            !in_interrupt() &&
+            paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
                 arch_enter_lazy_mmu_mode();
                 lazy = true;
         }
 
         for (i = 0; i < count; i++) {
-                ret = m2p_remove_override(pages[i], kmap_ops ?
-                                       &kmap_ops[i] : NULL);
+                pfn = page_to_pfn(pages[i]);
+                mfn = get_phys_to_machine(pfn);
+                if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                set_page_private(pages[i], INVALID_P2M_ENTRY);
+                WARN_ON(!PagePrivate(pages[i]));
+                ClearPagePrivate(pages[i]);
+                set_phys_to_machine(pfn, pages[i]->index);
+                if (m2p_override)
+                        ret = m2p_remove_override(pages[i],
+                                                  kmap_ops ?
+                                                   &kmap_ops[i] : NULL,
+                                                  mfn);
                 if (ret)
                         goto out;
         }
@@ -1027,8 +1076,22 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 
         return ret;
 }
+
+int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *map_ops,
+                    struct page **pages, unsigned int count)
+{
+        return __gnttab_unmap_refs(map_ops, NULL, pages, count, false);
+}
 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
 
+int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *map_ops,
+                                struct gnttab_map_grant_ref *kmap_ops,
+                                struct page **pages, unsigned int count)
+{
+        return __gnttab_unmap_refs(map_ops, kmap_ops, pages, count, true);
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs_userspace);
+
 static unsigned nr_status_frames(unsigned nr_grant_frames)
 {
         BUG_ON(grefs_per_grant_frame == 0);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 1eac0731c349..ebd8f218a788 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -75,14 +75,32 @@ static unsigned long xen_io_tlb_nslabs;
 
 static u64 start_dma_addr;
 
+/*
+ * Both of these functions should avoid PFN_PHYS because phys_addr_t
+ * can be 32bit when dma_addr_t is 64bit leading to a loss in
+ * information if the shift is done before casting to 64bit.
+ */
 static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
 {
-        return phys_to_machine(XPADDR(paddr)).maddr;
+        unsigned long mfn = pfn_to_mfn(PFN_DOWN(paddr));
+        dma_addr_t dma = (dma_addr_t)mfn << PAGE_SHIFT;
+
+        dma |= paddr & ~PAGE_MASK;
+
+        return dma;
 }
 
 static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
 {
-        return machine_to_phys(XMADDR(baddr)).paddr;
+        unsigned long pfn = mfn_to_pfn(PFN_DOWN(baddr));
+        dma_addr_t dma = (dma_addr_t)pfn << PAGE_SHIFT;
+        phys_addr_t paddr = dma;
+
+        BUG_ON(paddr != dma); /* truncation has occurred, should never happen */
+
+        paddr |= baddr & ~PAGE_MASK;
+
+        return paddr;
 }
 
 static inline dma_addr_t xen_virt_to_bus(void *address)
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index 21e18c18c7a1..745ad79c1d8e 100644
--- a/drivers/xen/xen-selfballoon.c
+++ b/drivers/xen/xen-selfballoon.c
@@ -175,6 +175,7 @@ static void frontswap_selfshrink(void)
 #endif /* CONFIG_FRONTSWAP */
 
 #define MB2PAGES(mb)    ((mb) << (20 - PAGE_SHIFT))
+#define PAGES2MB(pages) ((pages) >> (20 - PAGE_SHIFT))
 
 /*
  * Use current balloon size, the goal (vm_committed_as), and hysteresis
@@ -525,6 +526,7 @@ EXPORT_SYMBOL(register_xen_selfballooning);
 int xen_selfballoon_init(bool use_selfballooning, bool use_frontswap_selfshrink)
 {
         bool enable = false;
+        unsigned long reserve_pages;
 
         if (!xen_domain())
                 return -ENODEV;
@@ -549,6 +551,26 @@ int xen_selfballoon_init(bool use_selfballooning, bool use_frontswap_selfshrink)
         if (!enable)
                 return -ENODEV;
 
+        /*
+         * Give selfballoon_reserved_mb a default value(10% of total ram pages)
+         * to make selfballoon not so aggressive.
+         *
+         * There are mainly two reasons:
+         * 1) The original goal_page didn't consider some pages used by kernel
+         *    space, like slab pages and memory used by device drivers.
+         *
+         * 2) The balloon driver may not give back memory to guest OS fast
+         *    enough when the workload suddenly aquries a lot of physical memory.
+         *
+         * In both cases, the guest OS will suffer from memory pressure and
+         * OOM killer may be triggered.
+         * By reserving extra 10% of total ram pages, we can keep the system
+         * much more reliably and response faster in some cases.
+         */
+        if (!selfballoon_reserved_mb) {
+                reserve_pages = totalram_pages / 10;
+                selfballoon_reserved_mb = PAGES2MB(reserve_pages);
+        }
         schedule_delayed_work(&selfballoon_worker, selfballoon_interval * HZ);
 
         return 0;
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 5acb1e4ac0d3..7ad033dbc845 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -185,17 +185,21 @@ struct grant_frames {
 };
 extern struct grant_frames xen_auto_xlat_grant_frames;
 unsigned int gnttab_max_grant_frames(void);
-int gnttab_setup_auto_xlat_frames(unsigned long addr);
+int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
 void gnttab_free_auto_xlat_frames(void);
 
 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
 
 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
-                    struct gnttab_map_grant_ref *kmap_ops,
                     struct page **pages, unsigned int count);
+int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
+                              struct gnttab_map_grant_ref *kmap_ops,
+                              struct page **pages, unsigned int count);
 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
-                      struct gnttab_map_grant_ref *kunmap_ops,
                       struct page **pages, unsigned int count);
+int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *unmap_ops,
+                                struct gnttab_map_grant_ref *kunmap_ops,
+                                struct page **pages, unsigned int count);
 
 /* Perform a batch of grant map/copy operations. Retry every batch slot
  * for which the hypervisor returns GNTST_eagain. This is typically due