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 <mtosatti@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 92048a6..f54c4f9 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;