KVM: PPC: Book3S PR: Don't keep scanning HPTEG after we find a match

The loop in kvmppc_mmu_book3s_64_xlate() that looks up a translation
in the guest hashed page table (HPT) keeps going if it finds an
HPTE that matches but doesn't allow access.  This is incorrect; it
is different from what the hardware does, and there should never be
more than one matching HPTE anyway.  This fixes it to stop when any
matching HPTE is found.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index b871721c0050e8e3f04353f80c925f63c89afded..2e93bb50a71cb2714955203b871d02af0e7615ef 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -167,7 +167,6 @@ static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
        int i;
        u8 key = 0;
        bool found = false;
-       bool perm_err = false;
        int second = 0;
        ulong mp_ea = vcpu->arch.magic_page_ea;
 
@@ -248,11 +247,6 @@ do_second:
                                break;
                        }
 
-                       if (!gpte->may_read) {
-                               perm_err = true;
-                               continue;
-                       }
-
                        dprintk("KVM MMU: Translated 0x%lx [0x%llx] -> 0x%llx "
                                "-> 0x%lx\n",
                                eaddr, avpn, gpte->vpage, gpte->raddr);
@@ -281,6 +275,8 @@ do_second:
                if (pteg[i+1] != oldr)
                        copy_to_user((void __user *)ptegp, pteg, sizeof(pteg));
 
+               if (!gpte->may_read)
+                       return -EPERM;
                return 0;
        } else {
                dprintk("KVM MMU: No PTE found (ea=0x%lx sdr1=0x%llx "
@@ -296,13 +292,7 @@ do_second:
                }
        }
 
-
 no_page_found:
-
-
-       if (perm_err)
-               return -EPERM;
-
        return -ENOENT;
 
 no_seg_found: