KVM: reorganize hva_to_pfn
[platform/adaptation/renesas_rcar/renesas_kernel.git] / virt / kvm / kvm_main.c
index eafba99..aa4a38a 100644 (file)
@@ -678,6 +678,14 @@ void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new)
        slots->generation++;
 }
 
+static int check_memory_region_flags(struct kvm_userspace_memory_region *mem)
+{
+       if (mem->flags & ~KVM_MEM_LOG_DIRTY_PAGES)
+               return -EINVAL;
+
+       return 0;
+}
+
 /*
  * Allocate some memory and give it an address in the guest physical address
  * space.
@@ -698,6 +706,10 @@ int __kvm_set_memory_region(struct kvm *kvm,
        struct kvm_memory_slot old, new;
        struct kvm_memslots *slots, *old_memslots;
 
+       r = check_memory_region_flags(mem);
+       if (r)
+               goto out;
+
        r = -EINVAL;
        /* General sanity checks */
        if (mem->memory_size & (PAGE_SIZE - 1))
@@ -990,6 +1002,25 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(gfn_to_hva);
 
+/*
+ * The hva returned by this function is only allowed to be read.
+ * It should pair with kvm_read_hva() or kvm_read_hva_atomic().
+ */
+static unsigned long gfn_to_hva_read(struct kvm *kvm, gfn_t gfn)
+{
+       return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL);
+}
+
+static int kvm_read_hva(void *data, void __user *hva, int len)
+{
+       return __copy_from_user(data, hva, len);
+}
+
+static int kvm_read_hva_atomic(void *data, void __user *hva, int len)
+{
+       return __copy_from_user_inatomic(data, hva, len);
+}
+
 int get_user_page_nowait(struct task_struct *tsk, struct mm_struct *mm,
        unsigned long start, int write, struct page **page)
 {
@@ -1010,91 +1041,120 @@ static inline int check_user_page_hwpoison(unsigned long addr)
        return rc == -EHWPOISON;
 }
 
-static pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
-                       bool write_fault, bool *writable)
+/*
+ * The atomic path to get the writable pfn which will be stored in @pfn,
+ * true indicates success, otherwise false is returned.
+ */
+static bool hva_to_pfn_fast(unsigned long addr, bool atomic, bool *async,
+                           bool write_fault, bool *writable, pfn_t *pfn)
 {
        struct page *page[1];
-       int npages = 0;
-       pfn_t pfn;
-
-       /* we can do it either atomically or asynchronously, not both */
-       BUG_ON(atomic && async);
-
-       BUG_ON(!write_fault && !writable);
-
-       if (writable)
-               *writable = true;
+       int npages;
 
-       if (atomic || async)
-               npages = __get_user_pages_fast(addr, 1, 1, page);
+       if (!(async || atomic))
+               return false;
 
-       if (unlikely(npages != 1) && !atomic) {
-               might_sleep();
+       npages = __get_user_pages_fast(addr, 1, 1, page);
+       if (npages == 1) {
+               *pfn = page_to_pfn(page[0]);
 
                if (writable)
-                       *writable = write_fault;
-
-               if (async) {
-                       down_read(&current->mm->mmap_sem);
-                       npages = get_user_page_nowait(current, current->mm,
-                                                    addr, write_fault, page);
-                       up_read(&current->mm->mmap_sem);
-               } else
-                       npages = get_user_pages_fast(addr, 1, write_fault,
-                                                    page);
-
-               /* map read fault as writable if possible */
-               if (unlikely(!write_fault) && npages == 1) {
-                       struct page *wpage[1];
-
-                       npages = __get_user_pages_fast(addr, 1, 1, wpage);
-                       if (npages == 1) {
-                               *writable = true;
-                               put_page(page[0]);
-                               page[0] = wpage[0];
-                       }
-                       npages = 1;
-               }
+                       *writable = true;
+               return true;
        }
 
-       if (unlikely(npages != 1)) {
-               struct vm_area_struct *vma;
+       return false;
+}
+
+/*
+ * The slow path to get the pfn of the specified host virtual address,
+ * 1 indicates success, -errno is returned if error is detected.
+ */
+static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
+                          bool *writable, pfn_t *pfn)
+{
+       struct page *page[1];
+       int npages = 0;
 
-               if (atomic)
-                       return KVM_PFN_ERR_FAULT;
+       might_sleep();
 
-               down_read(&current->mm->mmap_sem);
-               if (npages == -EHWPOISON ||
-                       (!async && check_user_page_hwpoison(addr))) {
-                       up_read(&current->mm->mmap_sem);
-                       return KVM_PFN_ERR_HWPOISON;
-               }
+       if (writable)
+               *writable = write_fault;
 
-               vma = find_vma_intersection(current->mm, addr, addr+1);
-
-               if (vma == NULL)
-                       pfn = KVM_PFN_ERR_FAULT;
-               else if ((vma->vm_flags & VM_PFNMAP)) {
-                       pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) +
-                               vma->vm_pgoff;
-                       BUG_ON(!kvm_is_mmio_pfn(pfn));
-               } else {
-                       if (async && (vma->vm_flags & VM_WRITE))
-                               *async = true;
-                       pfn = KVM_PFN_ERR_FAULT;
-               }
+       if (async) {
+               down_read(&current->mm->mmap_sem);
+               npages = get_user_page_nowait(current, current->mm,
+                                             addr, write_fault, page);
                up_read(&current->mm->mmap_sem);
        } else
-               pfn = page_to_pfn(page[0]);
+               npages = get_user_pages_fast(addr, 1, write_fault,
+                                            page);
+       if (npages != 1)
+               return npages;
+
+       /* map read fault as writable if possible */
+       if (unlikely(!write_fault)) {
+               struct page *wpage[1];
+
+               npages = __get_user_pages_fast(addr, 1, 1, wpage);
+               if (npages == 1) {
+                       *writable = true;
+                       put_page(page[0]);
+                       page[0] = wpage[0];
+               }
 
-       return pfn;
+               npages = 1;
+       }
+       *pfn = page_to_pfn(page[0]);
+       return npages;
 }
 
-pfn_t hva_to_pfn_atomic(unsigned long addr)
+static pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
+                       bool write_fault, bool *writable)
 {
-       return hva_to_pfn(addr, true, NULL, true, NULL);
+       struct vm_area_struct *vma;
+       pfn_t pfn = 0;
+       int npages;
+
+       /* we can do it either atomically or asynchronously, not both */
+       BUG_ON(atomic && async);
+
+       BUG_ON(!write_fault && !writable);
+
+       if (hva_to_pfn_fast(addr, atomic, async, write_fault, writable, &pfn))
+               return pfn;
+
+       if (atomic)
+               return KVM_PFN_ERR_FAULT;
+
+       npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
+       if (npages == 1)
+               return pfn;
+
+       down_read(&current->mm->mmap_sem);
+       if (npages == -EHWPOISON ||
+             (!async && check_user_page_hwpoison(addr))) {
+               pfn = KVM_PFN_ERR_HWPOISON;
+               goto exit;
+       }
+
+       vma = find_vma_intersection(current->mm, addr, addr + 1);
+
+       if (vma == NULL)
+               pfn = KVM_PFN_ERR_FAULT;
+       else if ((vma->vm_flags & VM_PFNMAP)) {
+               pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) +
+                       vma->vm_pgoff;
+               BUG_ON(!kvm_is_mmio_pfn(pfn));
+       } else {
+               if (async && (vma->vm_flags & VM_WRITE))
+                       *async = true;
+               pfn = KVM_PFN_ERR_FAULT;
+       }
+exit:
+       up_read(&current->mm->mmap_sem);
+       return pfn;
 }
-EXPORT_SYMBOL_GPL(hva_to_pfn_atomic);
 
 static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic, bool *async,
                          bool write_fault, bool *writable)
@@ -1143,6 +1203,14 @@ pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
        return hva_to_pfn(addr, false, NULL, true, NULL);
 }
 
+pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn)
+{
+       unsigned long addr = gfn_to_hva_memslot(slot, gfn);
+
+       return hva_to_pfn(addr, true, NULL, true, NULL);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
+
 int gfn_to_page_many_atomic(struct kvm *kvm, gfn_t gfn, struct page **pages,
                                                                  int nr_pages)
 {
@@ -1186,8 +1254,9 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
 
 void kvm_release_page_clean(struct page *page)
 {
-       if (!is_error_page(page))
-               kvm_release_pfn_clean(page_to_pfn(page));
+       WARN_ON(is_error_page(page));
+
+       kvm_release_pfn_clean(page_to_pfn(page));
 }
 EXPORT_SYMBOL_GPL(kvm_release_page_clean);
 
@@ -1259,10 +1328,10 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
        int r;
        unsigned long addr;
 
-       addr = gfn_to_hva(kvm, gfn);
+       addr = gfn_to_hva_read(kvm, gfn);
        if (kvm_is_error_hva(addr))
                return -EFAULT;
-       r = __copy_from_user(data, (void __user *)addr + offset, len);
+       r = kvm_read_hva(data, (void __user *)addr + offset, len);
        if (r)
                return -EFAULT;
        return 0;
@@ -1297,11 +1366,11 @@ int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
        gfn_t gfn = gpa >> PAGE_SHIFT;
        int offset = offset_in_page(gpa);
 
-       addr = gfn_to_hva(kvm, gfn);
+       addr = gfn_to_hva_read(kvm, gfn);
        if (kvm_is_error_hva(addr))
                return -EFAULT;
        pagefault_disable();
-       r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
+       r = kvm_read_hva_atomic(data, (void __user *)addr + offset, len);
        pagefault_enable();
        if (r)
                return -EFAULT;