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>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e96cce170228cd7f0dcf7836c5d35f722165b1d9..917b9b50fab00026c094fdf66aaadfcaef03e3a1 100644 (file)
--- 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;