KVM: SVM: remove needless mmap_sem acquision from nested_svm_map

nested_svm_map unnecessarily takes mmap_sem around gfn_to_page, since
gfn_to_page / get_user_pages are responsible for it.

Signed-off-by: Marcelo Tosatti <[email protected]>
Acked-by: Alexander Graf <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 92048a626d4ebd563c54e146ebe28d3d911affc1..f54c4f9d28657ba80e53edb4d5a75e01508c1872 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1396,10 +1396,7 @@ static void *nested_svm_map(struct vcpu_svm *svm, u64 gpa, enum km_type idx)
 {
        struct page *page;
 
-       down_read(&current->mm->mmap_sem);
        page = gfn_to_page(svm->vcpu.kvm, gpa >> PAGE_SHIFT);
-       up_read(&current->mm->mmap_sem);
-
        if (is_error_page(page))
                goto error;