diff options
Diffstat (limited to 'arch/x86/kvm/paging_tmpl.h')
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 45 |
1 files changed, 31 insertions, 14 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 6bdca39829bc..d583bcd119fc 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * Kernel-based Virtual Machine driver for Linux * @@ -12,10 +13,6 @@ * Authors: * Yaniv Kamay <yaniv@qumranet.com> * Avi Kivity <avi@qumranet.com> - * - * This work is licensed under the terms of the GNU GPL, version 2. See - * the COPYING file in the top-level directory. - * */ /* @@ -140,16 +137,36 @@ static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, pt_element_t *table; struct page *page; - npages = get_user_pages_fast((unsigned long)ptep_user, 1, 1, &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); + npages = get_user_pages_fast((unsigned long)ptep_user, 1, FOLL_WRITE, &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(¤t->mm->mmap_sem); + vma = find_vma_intersection(current->mm, vaddr, vaddr + PAGE_SIZE); + if (!vma || !(vma->vm_flags & VM_PFNMAP)) { + up_read(¤t->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(¤t->mm->mmap_sem); + return -EFAULT; + } + ret = CMPXCHG(&table[index], orig_pte, new_pte); + memunmap(table); + up_read(¤t->mm->mmap_sem); + } return (ret != orig_pte); } |