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>

1 files changed, 60 insertions, 1 deletions

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index e4ce34c52ba1..ba53e59f558a 100644
--- 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;