[RFCv2 10/16] KVM: x86: Use GUP for page walk instead of __get_user()

[Kirill A. Shutemov]

The user mapping doesn't have the page mapping for protected memory.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 arch/x86/kvm/mmu/paging_tmpl.h | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 4dd6b1e5b8cf..258a6361b9b2 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -397,8 +397,14 @@ static int FNAME(walk_addr_generic)(struct guest_walker 
*walker,
                        goto error;
 
                ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
-               if (unlikely(__get_user(pte, ptep_user)))
-                       goto error;
+               if (vcpu->kvm->mem_protected) {
+                       if (copy_from_guest(&pte, host_addr + offset,
+                                           sizeof(pte), true))
+                               goto error;
+               } else {
+                       if (unlikely(__get_user(pte, ptep_user)))
+                               goto error;
+               }
                walker->ptep_user[walker->level - 1] = ptep_user;
 
                trace_kvm_mmu_paging_element(pte, walker->level);
-- 
2.26.2