MIPS: KVM: Propagate kseg0/mapped tlb fault errors

Propagate errors from kvm_mips_handle_kseg0_tlb_fault() and
kvm_mips_handle_mapped_seg_tlb_fault(), usually triggering an internal
error since they normally indicate the guest accessed bad physical
memory or the commpage in an unexpected way.

Fixes: 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

2 files changed, 35 insertions, 12 deletions

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 6eb52b9c9818..e788515f766b 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -1642,8 +1642,14 @@ enum emulation_result kvm_mips_emulate_cache(union mips_instruction inst,
 
         preempt_disable();
         if (KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG0) {
-                if (kvm_mips_host_tlb_lookup(vcpu, va) < 0)
-                        kvm_mips_handle_kseg0_tlb_fault(va, vcpu);
+                if (kvm_mips_host_tlb_lookup(vcpu, va) < 0 &&
+                    kvm_mips_handle_kseg0_tlb_fault(va, vcpu)) {
+                        kvm_err("%s: handling mapped kseg0 tlb fault for %lx, vcpu: %p, ASID: %#lx\n",
+                                __func__, va, vcpu, read_c0_entryhi());
+                        er = EMULATE_FAIL;
+                        preempt_enable();
+                        goto done;
+                }
         } else if ((KVM_GUEST_KSEGX(va) < KVM_GUEST_KSEG0) ||
                    KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG23) {
                 int index;
@@ -1680,12 +1686,18 @@ enum emulation_result kvm_mips_emulate_cache(union mips_instruction inst,
                                                                 run, vcpu);
                                 preempt_enable();
                                 goto dont_update_pc;
-                        } else {
-                                /*
-                                 * We fault an entry from the guest tlb to the
-                                 * shadow host TLB
-                                 */
-                                kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb);
+                        }
+                        /*
+                         * We fault an entry from the guest tlb to the
+                         * shadow host TLB
+                         */
+                        if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb)) {
+                                kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
+                                        __func__, va, index, vcpu,
+                                        read_c0_entryhi());
+                                er = EMULATE_FAIL;
+                                preempt_enable();
+                                goto done;
                         }
                 }
         } else {
@@ -2659,7 +2671,12 @@ enum emulation_result kvm_mips_handle_tlbmiss(u32 cause,
                          * OK we have a Guest TLB entry, now inject it into the
                          * shadow host TLB
                          */
-                        kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb);
+                        if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb)) {
+                                kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
+                                        __func__, va, index, vcpu,
+                                        read_c0_entryhi());
+                                er = EMULATE_FAIL;
+                        }
                 }
         }
 
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 6a8a21859502..6cfdcf55572d 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -368,9 +368,15 @@ u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu)
                                 local_irq_restore(flags);
                                 return KVM_INVALID_INST;
                         }
-                        kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
-                                                             &vcpu->arch.
-                                                             guest_tlb[index]);
+                        if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
+                                                &vcpu->arch.guest_tlb[index])) {
+                                kvm_err("%s: handling mapped seg tlb fault failed for %p, index: %u, vcpu: %p, ASID: %#lx\n",
+                                        __func__, opc, index, vcpu,
+                                        read_c0_entryhi());
+                                kvm_mips_dump_guest_tlbs(vcpu);
+                                local_irq_restore(flags);
+                                return KVM_INVALID_INST;
+                        }
                         inst = *(opc);
                 }
                 local_irq_restore(flags);