[PATCH 098/104] KVM: x86 emulator: imlpement jump conditional relative

Avi Kivity
2007-09-17T08:32:20Z

From: Nitin A Kamble <nitin.a.kamble@intel.com>

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>
---
drivers/kvm/x86_emulate.c | 61 ++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 60 insertions(+), 1 deletions(-)

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index e4ce34c..ba53e59 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;
--
1.5.3