KVM: x86 emulator: make (get|set)_dr() callback return error if it fails

Make (get|set)_dr() callback return error if it fails instead of
injecting exception behind emulator's back.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 061f7d37c9f7..d5979ecc2521 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3151,9 +3151,14 @@ twobyte_insn:
                         goto done;
                 }
 
-                ops->set_dr(c->modrm_reg,c->regs[c->modrm_rm] &
-                            ((ctxt->mode == X86EMUL_MODE_PROT64) ? ~0ULL : ~0U),
-                        ctxt->vcpu);
+                if (ops->set_dr(c->modrm_reg, c->regs[c->modrm_rm] &
+                                ((ctxt->mode == X86EMUL_MODE_PROT64) ?
+                                 ~0ULL : ~0U), ctxt->vcpu) < 0) {
+                        /* #UD condition is already handled by the code above */
+                        kvm_inject_gp(ctxt->vcpu, 0);
+                        goto done;
+                }
+
                 c->dst.type = OP_NONE;  /* no writeback */
                 break;
         case 0x30: