KVM: x86 emulator: imlpement jump conditional relative

Implement emulation of instruction:
    jump conditional rel
    opcodes: 0x0f 0x80 - 0x0f 0x8f

Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index e4ce34c52ba1e55182bdfccf63fa9c83d3f1e5fd..ba53e59f558a92a027651fc2f065ce4d06b7022e 100644 (file)
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -188,7 +188,10 @@ static u16 twobyte_table[256] = {
        /* 0x70 - 0x7F */
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        /* 0x80 - 0x8F */
-       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
+       ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
+       ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
+       ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
        /* 0x90 - 0x9F */
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        /* 0xA0 - 0xA7 */
@@ -479,6 +482,41 @@ static int read_descriptor(struct x86_emulate_ctxt *ctxt,
        return rc;
 }
 
+static int test_cc(unsigned int condition, unsigned int flags)
+{
+       int rc = 0;
+
+       switch ((condition & 15) >> 1) {
+       case 0: /* o */
+               rc |= (flags & EFLG_OF);
+               break;
+       case 1: /* b/c/nae */
+               rc |= (flags & EFLG_CF);
+               break;
+       case 2: /* z/e */
+               rc |= (flags & EFLG_ZF);
+               break;
+       case 3: /* be/na */
+               rc |= (flags & (EFLG_CF|EFLG_ZF));
+               break;
+       case 4: /* s */
+               rc |= (flags & EFLG_SF);
+               break;
+       case 5: /* p/pe */
+               rc |= (flags & EFLG_PF);
+               break;
+       case 7: /* le/ng */
+               rc |= (flags & EFLG_ZF);
+               /* fall through */
+       case 6: /* l/nge */
+               rc |= (!(flags & EFLG_SF) != !(flags & EFLG_OF));
+               break;
+       }
+
+       /* Odd condition identifiers (lsb == 1) have inverted sense. */
+       return (!!rc ^ (condition & 1));
+}
+
 int
 x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 {
@@ -1486,6 +1524,27 @@ twobyte_special_insn:
                }
                rc = X86EMUL_CONTINUE;
                break;
+       case 0x80 ... 0x8f: /* jnz rel, etc*/ {
+               long int rel;
+
+               switch (op_bytes) {
+               case 2:
+                       rel = insn_fetch(s16, 2, _eip);
+                       break;
+               case 4:
+                       rel = insn_fetch(s32, 4, _eip);
+                       break;
+               case 8:
+                       rel = insn_fetch(s64, 8, _eip);
+                       break;
+               default:
+                       DPRINTF("jnz: Invalid op_bytes\n");
+                       goto cannot_emulate;
+               }
+               if (test_cc(b, _eflags))
+                       JMP_REL(rel);
+               break;
+       }
        case 0xc7:              /* Grp9 (cmpxchg8b) */
                {
                        u64 old, new;