KVM: x86 emulator: trap and propagate #DE from DIV and IDIV

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e96cce170228..917b9b50fab0 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -504,6 +504,12 @@ static void emulate_ts(struct x86_emulate_ctxt *ctxt, int err)
         emulate_exception(ctxt, TS_VECTOR, err, true);
 }
 
+static int emulate_de(struct x86_emulate_ctxt *ctxt)
+{
+        emulate_exception(ctxt, DE_VECTOR, 0, false);
+        return X86EMUL_PROPAGATE_FAULT;
+}
+
 static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
                               struct x86_emulate_ops *ops,
                               unsigned long eip, u8 *dest)
@@ -1458,6 +1464,7 @@ static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
         struct decode_cache *c = &ctxt->decode;
         unsigned long *rax = &c->regs[VCPU_REGS_RAX];
         unsigned long *rdx = &c->regs[VCPU_REGS_RDX];
+        u8 de = 0;
 
         switch (c->modrm_reg) {
         case 0 ... 1:   /* test */
@@ -1476,14 +1483,18 @@ static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
                 emulate_1op_rax_rdx("imul", c->src, *rax, *rdx, ctxt->eflags);
                 break;
         case 6: /* div */
-                emulate_1op_rax_rdx("div", c->src, *rax, *rdx, ctxt->eflags);
+                emulate_1op_rax_rdx_ex("div", c->src, *rax, *rdx,
+                                       ctxt->eflags, de);
                 break;
         case 7: /* idiv */
-                emulate_1op_rax_rdx("idiv", c->src, *rax, *rdx, ctxt->eflags);
+                emulate_1op_rax_rdx_ex("idiv", c->src, *rax, *rdx,
+                                       ctxt->eflags, de);
                 break;
         default:
                 return X86EMUL_UNHANDLEABLE;
         }
+        if (de)
+                return emulate_de(ctxt);
         return X86EMUL_CONTINUE;
 }
 
@@ -3413,8 +3424,9 @@ special_insn:
                 ctxt->eflags ^= EFLG_CF;
                 break;
         case 0xf6 ... 0xf7:     /* Grp3 */
-                if (emulate_grp3(ctxt, ops) != X86EMUL_CONTINUE)
-                        goto cannot_emulate;
+                rc = emulate_grp3(ctxt, ops);
+                if (rc != X86EMUL_CONTINUE)
+                        goto done;
                 break;
         case 0xf8: /* clc */
                 ctxt->eflags &= ~EFLG_CF;