KVM: x86 emulator: add bsf/bsr instruction emulation

Add bsf/bsr instruction emulation (opcode 0x0f 0xbc~0xbd)

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8617c344405d188f7d8774d1edab1fae66f84566..f6b124fcc3fd1023c0694bbdc59aeefd6a03dce1 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2379,8 +2379,8 @@ static struct opcode twobyte_table[256] = {
        /* 0xB8 - 0xBF */
        N, N,
        G(BitOp, group8), D(DstMem | SrcReg | ModRM | BitOp | Lock),
-       N, N, D(ByteOp | DstReg | SrcMem | ModRM | Mov),
-           D(DstReg | SrcMem16 | ModRM | Mov),
+       D(DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),
+       D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
        /* 0xC0 - 0xCF */
        N, N, N, D(DstMem | SrcReg | ModRM | Mov),
        N, N, N, GD(0, &group9),
@@ -3511,6 +3511,30 @@ twobyte_insn:
              btc:              /* btc */
                emulate_2op_SrcV_nobyte("btc", c->src, c->dst, ctxt->eflags);
                break;
+       case 0xbc: {            /* bsf */
+               u8 zf;
+               __asm__ ("bsf %2, %0; setz %1"
+                        : "=r"(c->dst.val), "=q"(zf)
+                        : "r"(c->src.val));
+               ctxt->eflags &= ~X86_EFLAGS_ZF;
+               if (zf) {
+                       ctxt->eflags |= X86_EFLAGS_ZF;
+                       c->dst.type = OP_NONE;  /* Disable writeback. */
+               }
+               break;
+       }
+       case 0xbd: {            /* bsr */
+               u8 zf;
+               __asm__ ("bsr %2, %0; setz %1"
+                        : "=r"(c->dst.val), "=q"(zf)
+                        : "r"(c->src.val));
+               ctxt->eflags &= ~X86_EFLAGS_ZF;
+               if (zf) {
+                       ctxt->eflags |= X86_EFLAGS_ZF;
+                       c->dst.type = OP_NONE;  /* Disable writeback. */
+               }
+               break;
+       }
        case 0xbe ... 0xbf:     /* movsx */
                c->dst.bytes = c->op_bytes;
                c->dst.val = (c->d & ByteOp) ? (s8) c->src.val :