1 files changed, 46 insertions, 37 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 47000be25479..f86a47c2f255 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -300,19 +300,6 @@ static struct kvm *kvm_create_vm(void)
         return kvm;
 }
 
-static void kvm_free_userspace_physmem(struct kvm_memory_slot *free)
-{
-        int i;
-
-        for (i = 0; i < free->npages; ++i) {
-                if (free->phys_mem[i]) {
-                        if (!PageReserved(free->phys_mem[i]))
-                                SetPageDirty(free->phys_mem[i]);
-                        page_cache_release(free->phys_mem[i]);
-                }
-        }
-}
-
 static void kvm_free_kernel_physmem(struct kvm_memory_slot *free)
 {
         int i;
@@ -330,9 +317,7 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
 {
         if (!dont || free->phys_mem != dont->phys_mem)
                 if (free->phys_mem) {
-                        if (free->user_alloc)
-                                kvm_free_userspace_physmem(free);
-                        else
+                        if (!free->user_alloc)
                                 kvm_free_kernel_physmem(free);
                         vfree(free->phys_mem);
                 }
@@ -361,7 +346,7 @@ static void free_pio_guest_pages(struct kvm_vcpu *vcpu)
 
         for (i = 0; i < ARRAY_SIZE(vcpu->pio.guest_pages); ++i)
                 if (vcpu->pio.guest_pages[i]) {
-                        __free_page(vcpu->pio.guest_pages[i]);
+                        kvm_release_page(vcpu->pio.guest_pages[i]);
                         vcpu->pio.guest_pages[i] = NULL;
                 }
 }
@@ -752,19 +737,8 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
                 memset(new.phys_mem, 0, npages * sizeof(struct page *));
                 memset(new.rmap, 0, npages * sizeof(*new.rmap));
                 if (user_alloc) {
-                        unsigned long pages_num;
-
                         new.user_alloc = 1;
-                        down_read(&current->mm->mmap_sem);
-
-                        pages_num = get_user_pages(current, current->mm,
-                                                   mem->userspace_addr,
-                                                   npages, 1, 1, new.phys_mem,
-                                                   NULL);
-
-                        up_read(&current->mm->mmap_sem);
-                        if (pages_num != npages)
-                                goto out_unlock;
+                        new.userspace_addr = mem->userspace_addr;
                 } else {
                         for (i = 0; i < npages; ++i) {
                                 new.phys_mem[i] = alloc_page(GFP_HIGHUSER
@@ -1039,12 +1013,39 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
 
         gfn = unalias_gfn(kvm, gfn);
         slot = __gfn_to_memslot(kvm, gfn);
-        if (!slot)
+        if (!slot) {
+                get_page(bad_page);
                 return bad_page;
+        }
+        if (slot->user_alloc) {
+                struct page *page[1];
+                int npages;
+
+                down_read(&current->mm->mmap_sem);
+                npages = get_user_pages(current, current->mm,
+                                        slot->userspace_addr
+                                        + (gfn - slot->base_gfn) * PAGE_SIZE, 1,
+                                        1, 1, page, NULL);
+                up_read(&current->mm->mmap_sem);
+                if (npages != 1) {
+                        get_page(bad_page);
+                        return bad_page;
+                }
+                return page[0];
+        }
+        get_page(slot->phys_mem[gfn - slot->base_gfn]);
         return slot->phys_mem[gfn - slot->base_gfn];
 }
 EXPORT_SYMBOL_GPL(gfn_to_page);
 
+void kvm_release_page(struct page *page)
+{
+        if (!PageReserved(page))
+                SetPageDirty(page);
+        put_page(page);
+}
+EXPORT_SYMBOL_GPL(kvm_release_page);
+
 static int next_segment(unsigned long len, int offset)
 {
         if (len > PAGE_SIZE - offset)
@@ -1060,13 +1061,16 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
         struct page *page;
 
         page = gfn_to_page(kvm, gfn);
-        if (is_error_page(page))
+        if (is_error_page(page)) {
+                kvm_release_page(page);
                 return -EFAULT;
+        }
         page_virt = kmap_atomic(page, KM_USER0);
 
         memcpy(data, page_virt + offset, len);
 
         kunmap_atomic(page_virt, KM_USER0);
+        kvm_release_page(page);
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest_page);
@@ -1098,14 +1102,17 @@ int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
         struct page *page;
 
         page = gfn_to_page(kvm, gfn);
-        if (is_error_page(page))
+        if (is_error_page(page)) {
+                kvm_release_page(page);
                 return -EFAULT;
+        }
         page_virt = kmap_atomic(page, KM_USER0);
 
         memcpy(page_virt + offset, data, len);
 
         kunmap_atomic(page_virt, KM_USER0);
         mark_page_dirty(kvm, gfn);
+        kvm_release_page(page);
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_write_guest_page);
@@ -1136,13 +1143,16 @@ int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len)
         struct page *page;
 
         page = gfn_to_page(kvm, gfn);
-        if (is_error_page(page))
+        if (is_error_page(page)) {
+                kvm_release_page(page);
                 return -EFAULT;
+        }
         page_virt = kmap_atomic(page, KM_USER0);
 
         memset(page_virt + offset, 0, len);
 
         kunmap_atomic(page_virt, KM_USER0);
+        kvm_release_page(page);
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_clear_guest_page);
@@ -2070,8 +2080,6 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
         for (i = 0; i < nr_pages; ++i) {
                 mutex_lock(&vcpu->kvm->lock);
                 page = gva_to_page(vcpu, address + i * PAGE_SIZE);
-                if (page)
-                        get_page(page);
                 vcpu->pio.guest_pages[i] = page;
                 mutex_unlock(&vcpu->kvm->lock);
                 if (!page) {
@@ -3074,9 +3082,10 @@ static struct page *kvm_vm_nopage(struct vm_area_struct *vma,
 
         pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
         page = gfn_to_page(kvm, pgoff);
-        if (is_error_page(page))
+        if (is_error_page(page)) {
+                kvm_release_page(page);
                 return NOPAGE_SIGBUS;
-        get_page(page);
+        }
         if (type != NULL)
                 *type = VM_FAULT_MINOR;