KVM: switch to get_user_pages_fast

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / virt / kvm / kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2907d05cfcc348a4dd32aeab919b5a62dcaf1ab6..cd34f73513d3633b8ef1ad772ddc1650e5bde74f 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -723,9 +723,6 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(gfn_to_hva);
 
-/*
- * Requires current->mm->mmap_sem to be held
- */
 pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
 {
        struct page *page[1];
@@ -741,20 +738,23 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
                return page_to_pfn(bad_page);
        }
 
-       npages = get_user_pages(current, current->mm, addr, 1, 1, 0, page,
-                               NULL);
+       npages = get_user_pages_fast(addr, 1, 1, page);
 
        if (unlikely(npages != 1)) {
                struct vm_area_struct *vma;
 
+               down_read(&current->mm->mmap_sem);
                vma = find_vma(current->mm, addr);
+
                if (vma == NULL || addr < vma->vm_start ||
                    !(vma->vm_flags & VM_PFNMAP)) {
+                       up_read(&current->mm->mmap_sem);
                        get_page(bad_page);
                        return page_to_pfn(bad_page);
                }
 
                pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+               up_read(&current->mm->mmap_sem);
                BUG_ON(!is_mmio_pfn(pfn));
        } else
                pfn = page_to_pfn(page[0]);