1 files changed, 256 insertions, 18 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index df40bf74ea75..42b3b9ed641d 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -56,6 +56,131 @@
 #include "multicalls.h"
 #include "mmu.h"
 
+#define P2M_ENTRIES_PER_PAGE    (PAGE_SIZE / sizeof(unsigned long))
+#define TOP_ENTRIES             (MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)
+
+/* Placeholder for holes in the address space */
+static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE]
+        __attribute__((section(".data.page_aligned"))) =
+                { [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
+
+ /* Array of pointers to pages containing p2m entries */
+static unsigned long *p2m_top[TOP_ENTRIES]
+        __attribute__((section(".data.page_aligned"))) =
+                { [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
+
+/* Arrays of p2m arrays expressed in mfns used for save/restore */
+static unsigned long p2m_top_mfn[TOP_ENTRIES]
+        __attribute__((section(".bss.page_aligned")));
+
+static unsigned long p2m_top_mfn_list[
+                        PAGE_ALIGN(TOP_ENTRIES / P2M_ENTRIES_PER_PAGE)]
+        __attribute__((section(".bss.page_aligned")));
+
+static inline unsigned p2m_top_index(unsigned long pfn)
+{
+        BUG_ON(pfn >= MAX_DOMAIN_PAGES);
+        return pfn / P2M_ENTRIES_PER_PAGE;
+}
+
+static inline unsigned p2m_index(unsigned long pfn)
+{
+        return pfn % P2M_ENTRIES_PER_PAGE;
+}
+
+/* Build the parallel p2m_top_mfn structures */
+void xen_setup_mfn_list_list(void)
+{
+        unsigned pfn, idx;
+
+        for(pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_ENTRIES_PER_PAGE) {
+                unsigned topidx = p2m_top_index(pfn);
+
+                p2m_top_mfn[topidx] = virt_to_mfn(p2m_top[topidx]);
+        }
+
+        for(idx = 0; idx < ARRAY_SIZE(p2m_top_mfn_list); idx++) {
+                unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
+                p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
+        }
+
+        BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+
+        HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
+                virt_to_mfn(p2m_top_mfn_list);
+        HYPERVISOR_shared_info->arch.max_pfn = xen_start_info->nr_pages;
+}
+
+/* Set up p2m_top to point to the domain-builder provided p2m pages */
+void __init xen_build_dynamic_phys_to_machine(void)
+{
+        unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
+        unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
+        unsigned pfn;
+
+        for(pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
+                unsigned topidx = p2m_top_index(pfn);
+
+                p2m_top[topidx] = &mfn_list[pfn];
+        }
+}
+
+unsigned long get_phys_to_machine(unsigned long pfn)
+{
+        unsigned topidx, idx;
+
+        if (unlikely(pfn >= MAX_DOMAIN_PAGES))
+                return INVALID_P2M_ENTRY;
+
+        topidx = p2m_top_index(pfn);
+        idx = p2m_index(pfn);
+        return p2m_top[topidx][idx];
+}
+EXPORT_SYMBOL_GPL(get_phys_to_machine);
+
+static void alloc_p2m(unsigned long **pp, unsigned long *mfnp)
+{
+        unsigned long *p;
+        unsigned i;
+
+        p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);
+        BUG_ON(p == NULL);
+
+        for(i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
+                p[i] = INVALID_P2M_ENTRY;
+
+        if (cmpxchg(pp, p2m_missing, p) != p2m_missing)
+                free_page((unsigned long)p);
+        else
+                *mfnp = virt_to_mfn(p);
+}
+
+void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+        unsigned topidx, idx;
+
+        if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
+                BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
+                return;
+        }
+
+        if (unlikely(pfn >= MAX_DOMAIN_PAGES)) {
+                BUG_ON(mfn != INVALID_P2M_ENTRY);
+                return;
+        }
+
+        topidx = p2m_top_index(pfn);
+        if (p2m_top[topidx] == p2m_missing) {
+                /* no need to allocate a page to store an invalid entry */
+                if (mfn == INVALID_P2M_ENTRY)
+                        return;
+                alloc_p2m(&p2m_top[topidx], &p2m_top_mfn[topidx]);
+        }
+
+        idx = p2m_index(pfn);
+        p2m_top[topidx][idx] = mfn;
+}
+
 xmaddr_t arbitrary_virt_to_machine(unsigned long address)
 {
         unsigned int level;
@@ -98,24 +223,60 @@ void make_lowmem_page_readwrite(void *vaddr)
 }
 
 
-void xen_set_pmd(pmd_t *ptr, pmd_t val)
+static bool page_pinned(void *ptr)
+{
+        struct page *page = virt_to_page(ptr);
+
+        return PagePinned(page);
+}
+
+static void extend_mmu_update(const struct mmu_update *update)
 {
         struct multicall_space mcs;
         struct mmu_update *u;
 
-        preempt_disable();
+        mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
+
+        if (mcs.mc != NULL)
+                mcs.mc->args[1]++;
+        else {
+                mcs = __xen_mc_entry(sizeof(*u));
+                MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+        }
 
-        mcs = xen_mc_entry(sizeof(*u));
         u = mcs.args;
-        u->ptr = virt_to_machine(ptr).maddr;
-        u->val = pmd_val_ma(val);
-        MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+        *u = *update;
+}
+
+void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
+{
+        struct mmu_update u;
+
+        preempt_disable();
+
+        xen_mc_batch();
+
+        u.ptr = virt_to_machine(ptr).maddr;
+        u.val = pmd_val_ma(val);
+        extend_mmu_update(&u);
 
         xen_mc_issue(PARAVIRT_LAZY_MMU);
 
         preempt_enable();
 }
 
+void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+        /* If page is not pinned, we can just update the entry
+           directly */
+        if (!page_pinned(ptr)) {
+                *ptr = val;
+                return;
+        }
+
+        xen_set_pmd_hyper(ptr, val);
+}
+
 /*
  * Associate a virtual page frame with a given physical page frame
  * and protection flags for that frame.
@@ -179,13 +340,33 @@ out:
                 preempt_enable();
 }
 
+pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+        /* Just return the pte as-is.  We preserve the bits on commit */
+        return *ptep;
+}
+
+void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
+                                 pte_t *ptep, pte_t pte)
+{
+        struct mmu_update u;
+
+        xen_mc_batch();
+
+        u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
+        u.val = pte_val_ma(pte);
+        extend_mmu_update(&u);
+
+        xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
 /* Assume pteval_t is equivalent to all the other *val_t types. */
 static pteval_t pte_mfn_to_pfn(pteval_t val)
 {
         if (val & _PAGE_PRESENT) {
                 unsigned long mfn = (val & PTE_MASK) >> PAGE_SHIFT;
                 pteval_t flags = val & ~PTE_MASK;
-                val = (mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
+                val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
         }
 
         return val;
@@ -196,7 +377,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
         if (val & _PAGE_PRESENT) {
                 unsigned long pfn = (val & PTE_MASK) >> PAGE_SHIFT;
                 pteval_t flags = val & ~PTE_MASK;
-                val = (pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
+                val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
         }
 
         return val;
@@ -229,24 +410,35 @@ pmdval_t xen_pmd_val(pmd_t pmd)
         return pte_mfn_to_pfn(pmd.pmd);
 }
 
-void xen_set_pud(pud_t *ptr, pud_t val)
+void xen_set_pud_hyper(pud_t *ptr, pud_t val)
 {
-        struct multicall_space mcs;
-        struct mmu_update *u;
+        struct mmu_update u;
 
         preempt_disable();
 
-        mcs = xen_mc_entry(sizeof(*u));
-        u = mcs.args;
-        u->ptr = virt_to_machine(ptr).maddr;
-        u->val = pud_val_ma(val);
-        MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+        xen_mc_batch();
+
+        u.ptr = virt_to_machine(ptr).maddr;
+        u.val = pud_val_ma(val);
+        extend_mmu_update(&u);
 
         xen_mc_issue(PARAVIRT_LAZY_MMU);
 
         preempt_enable();
 }
 
+void xen_set_pud(pud_t *ptr, pud_t val)
+{
+        /* If page is not pinned, we can just update the entry
+           directly */
+        if (!page_pinned(ptr)) {
+                *ptr = val;
+                return;
+        }
+
+        xen_set_pud_hyper(ptr, val);
+}
+
 void xen_set_pte(pte_t *ptep, pte_t pte)
 {
         ptep->pte_high = pte.pte_high;
@@ -268,7 +460,7 @@ void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 
 void xen_pmd_clear(pmd_t *pmdp)
 {
-        xen_set_pmd(pmdp, __pmd(0));
+        set_pmd(pmdp, __pmd(0));
 }
 
 pmd_t xen_make_pmd(pmdval_t pmd)
@@ -441,6 +633,29 @@ void xen_pgd_pin(pgd_t *pgd)
         xen_mc_issue(0);
 }
 
+/*
+ * On save, we need to pin all pagetables to make sure they get their
+ * mfns turned into pfns.  Search the list for any unpinned pgds and pin
+ * them (unpinned pgds are not currently in use, probably because the
+ * process is under construction or destruction).
+ */
+void xen_mm_pin_all(void)
+{
+        unsigned long flags;
+        struct page *page;
+
+        spin_lock_irqsave(&pgd_lock, flags);
+
+        list_for_each_entry(page, &pgd_list, lru) {
+                if (!PagePinned(page)) {
+                        xen_pgd_pin((pgd_t *)page_address(page));
+                        SetPageSavePinned(page);
+                }
+        }
+
+        spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
 /* The init_mm pagetable is really pinned as soon as its created, but
    that's before we have page structures to store the bits.  So do all
    the book-keeping now. */
@@ -498,6 +713,29 @@ static void xen_pgd_unpin(pgd_t *pgd)
         xen_mc_issue(0);
 }
 
+/*
+ * On resume, undo any pinning done at save, so that the rest of the
+ * kernel doesn't see any unexpected pinned pagetables.
+ */
+void xen_mm_unpin_all(void)
+{
+        unsigned long flags;
+        struct page *page;
+
+        spin_lock_irqsave(&pgd_lock, flags);
+
+        list_for_each_entry(page, &pgd_list, lru) {
+                if (PageSavePinned(page)) {
+                        BUG_ON(!PagePinned(page));
+                        printk("unpinning pinned %p\n", page_address(page));
+                        xen_pgd_unpin((pgd_t *)page_address(page));
+                        ClearPageSavePinned(page);
+                }
+        }
+
+        spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
 void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
 {
         spin_lock(&next->page_table_lock);
@@ -591,7 +829,7 @@ void xen_exit_mmap(struct mm_struct *mm)
         spin_lock(&mm->page_table_lock);
 
         /* pgd may not be pinned in the error exit path of execve */
-        if (PagePinned(virt_to_page(mm->pgd)))
+        if (page_pinned(mm->pgd))
                 xen_pgd_unpin(mm->pgd);
 
         spin_unlock(&mm->page_table_lock);