Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[linux-2.6-microblaze.git] / arch / x86 / kvm / paging_tmpl.h

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 0871503..367a47d 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -141,15 +141,35 @@ static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
        struct page *page;
 
        npages = get_user_pages_fast((unsigned long)ptep_user, 1, FOLL_WRITE, &page);
-       /* Check if the user is doing something meaningless. */
-       if (unlikely(npages != 1))
-               return -EFAULT;
-
-       table = kmap_atomic(page);
-       ret = CMPXCHG(&table[index], orig_pte, new_pte);
-       kunmap_atomic(table);
-
-       kvm_release_page_dirty(page);
+       if (likely(npages == 1)) {
+               table = kmap_atomic(page);
+               ret = CMPXCHG(&table[index], orig_pte, new_pte);
+               kunmap_atomic(table);
+
+               kvm_release_page_dirty(page);
+       } else {
+               struct vm_area_struct *vma;
+               unsigned long vaddr = (unsigned long)ptep_user & PAGE_MASK;
+               unsigned long pfn;
+               unsigned long paddr;
+
+               down_read(&current->mm->mmap_sem);
+               vma = find_vma_intersection(current->mm, vaddr, vaddr + PAGE_SIZE);
+               if (!vma || !(vma->vm_flags & VM_PFNMAP)) {
+                       up_read(&current->mm->mmap_sem);
+                       return -EFAULT;
+               }
+               pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+               paddr = pfn << PAGE_SHIFT;
+               table = memremap(paddr, PAGE_SIZE, MEMREMAP_WB);
+               if (!table) {
+                       up_read(&current->mm->mmap_sem);
+                       return -EFAULT;
+               }
+               ret = CMPXCHG(&table[index], orig_pte, new_pte);
+               memunmap(table);
+               up_read(&current->mm->mmap_sem);
+       }
 
        return (ret != orig_pte);
 }