Merge tag 'stable/for-linus-3.14-rc0-late-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen bugfixes from Konrad Rzeszutek Wilk:
 "Bug-fixes for the new features that were added during this cycle.

  There are also two fixes for long-standing issues for which we have a
  solution: grant-table operations extra work that was not needed
  causing performance issues and the self balloon code was too
  aggressive causing OOMs.

  Details:
   - Xen ARM couldn't use the new FIFO events
   - Xen ARM couldn't use the SWIOTLB if compiled as 32-bit with 64-bit PCIe devices.
   - Grant table were doing needless M2P operations.
   - Ratchet down the self-balloon code so it won't OOM.
   - Fix misplaced kfree in Xen PVH error code paths"

* tag 'stable/for-linus-3.14-rc0-late-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pvh: Fix misplaced kfree from xlated_setup_gnttab_pages
  drivers: xen: deaggressive selfballoon driver
  xen/grant-table: Avoid m2p_override during mapping
  xen/gnttab: Use phys_addr_t to describe the grant frame base address
  xen: swiotlb: handle sizeof(dma_addr_t) != sizeof(phys_addr_t)
  arm/xen: Initialize event channels earlier

5 files changed, 135 insertions, 32 deletions

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;