Merge tag 'stable/for-linus-3.12-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen fixes from Konrad Rzeszutek Wilk:
 "Bug-fixes and one update to the kernel-paramters.txt documentation.

   - Fix PV spinlocks triggering jump_label code bug
   - Remove extraneous code in the tpm front driver
   - Fix ballooning out of pages when non-preemptible
   - Fix deadlock when using a 32-bit initial domain with large amount
     of memory
   - Add xen_nopvpsin parameter to the documentation"

* tag 'stable/for-linus-3.12-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/spinlock: Document the xen_nopvspin parameter.
  xen/p2m: check MFN is in range before using the m2p table
  xen/balloon: don't alloc page while non-preemptible
  xen: Do not enable spinlocks before jump_label_init() has executed
  tpm: xen-tpmfront: Remove the locality sysfs attribute
  tpm: xen-tpmfront: Fix default durations

3 files changed, 48 insertions, 19 deletions

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 6aef9fbc09b7..b913915e8e63 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -79,30 +79,38 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn)
         return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
 }
 
-static inline unsigned long mfn_to_pfn(unsigned long mfn)
+static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
 {
         unsigned long pfn;
-        int ret = 0;
+        int ret;
 
         if (xen_feature(XENFEAT_auto_translated_physmap))
                 return mfn;
 
-        if (unlikely(mfn >= machine_to_phys_nr)) {
-                pfn = ~0;
-                goto try_override;
-        }
-        pfn = 0;
+        if (unlikely(mfn >= machine_to_phys_nr))
+                return ~0;
+
         /*
          * The array access can fail (e.g., device space beyond end of RAM).
          * In such cases it doesn't matter what we return (we return garbage),
          * but we must handle the fault without crashing!
          */
         ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
-try_override:
-        /* ret might be < 0 if there are no entries in the m2p for mfn */
         if (ret < 0)
-                pfn = ~0;
-        else if (get_phys_to_machine(pfn) != mfn)
+                return ~0;
+
+        return pfn;
+}
+
+static inline unsigned long mfn_to_pfn(unsigned long mfn)
+{
+        unsigned long pfn;
+
+        if (xen_feature(XENFEAT_auto_translated_physmap))
+                return mfn;
+
+        pfn = mfn_to_pfn_no_overrides(mfn);
+        if (get_phys_to_machine(pfn) != mfn) {
                 /*
                  * If this appears to be a foreign mfn (because the pfn
                  * doesn't map back to the mfn), then check the local override
@@ -111,6 +119,7 @@ try_override:
                  * m2p_find_override_pfn returns ~0 if it doesn't find anything.
                  */
                 pfn = m2p_find_override_pfn(mfn, ~0);
+        }
 
         /* 
          * pfn is ~0 if there are no entries in the m2p for mfn or if the
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8b901e8d782d..a61c7d5811be 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -879,7 +879,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
         unsigned long uninitialized_var(address);
         unsigned level;
         pte_t *ptep = NULL;
-        int ret = 0;
 
         pfn = page_to_pfn(page);
         if (!PageHighMem(page)) {
@@ -926,8 +925,8 @@ int m2p_add_override(unsigned long mfn, struct page *page,
          * frontend pages while they are being shared with the backend,
          * because mfn_to_pfn (that ends up being called by GUPF) will
          * return the backend pfn rather than the frontend pfn. */
-        ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
-        if (ret == 0 && get_phys_to_machine(pfn) == mfn)
+        pfn = mfn_to_pfn_no_overrides(mfn);
+        if (get_phys_to_machine(pfn) == mfn)
                 set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));
 
         return 0;
@@ -942,7 +941,6 @@ int m2p_remove_override(struct page *page,
         unsigned long uninitialized_var(address);
         unsigned level;
         pte_t *ptep = NULL;
-        int ret = 0;
 
         pfn = page_to_pfn(page);
         mfn = get_phys_to_machine(pfn);
@@ -1029,8 +1027,8 @@ int m2p_remove_override(struct page *page,
          * the original pfn causes mfn_to_pfn(mfn) to return the frontend
          * pfn again. */
         mfn &= ~FOREIGN_FRAME_BIT;
-        ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
-        if (ret == 0 && get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) &&
+        pfn = mfn_to_pfn_no_overrides(mfn);
+        if (get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) &&
                         m2p_find_override(mfn) == NULL)
                 set_phys_to_machine(pfn, mfn);
 
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 253f63fceea1..be6b86078957 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -259,6 +259,14 @@ void xen_uninit_lock_cpu(int cpu)
 }
 
 
+/*
+ * Our init of PV spinlocks is split in two init functions due to us
+ * using paravirt patching and jump labels patching and having to do
+ * all of this before SMP code is invoked.
+ *
+ * The paravirt patching needs to be done _before_ the alternative asm code
+ * is started, otherwise we would not patch the core kernel code.
+ */
 void __init xen_init_spinlocks(void)
 {
 
@@ -267,12 +275,26 @@ void __init xen_init_spinlocks(void)
                 return;
         }
 
-        static_key_slow_inc(&paravirt_ticketlocks_enabled);
-
         pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
         pv_lock_ops.unlock_kick = xen_unlock_kick;
 }
 
+/*
+ * While the jump_label init code needs to happend _after_ the jump labels are
+ * enabled and before SMP is started. Hence we use pre-SMP initcall level
+ * init. We cannot do it in xen_init_spinlocks as that is done before
+ * jump labels are activated.
+ */
+static __init int xen_init_spinlocks_jump(void)
+{
+        if (!xen_pvspin)
+                return 0;
+
+        static_key_slow_inc(&paravirt_ticketlocks_enabled);
+        return 0;
+}
+early_initcall(xen_init_spinlocks_jump);
+
 static __init int xen_parse_nopvspin(char *arg)
 {
         xen_pvspin = false;