lkml.org 
[lkml]   [2008]   [Jan]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 16/54] KVM: x86 emulator: Move rep processing before instruction execution
    Date
    Currently rep processing is handled somewhere in the middle of instruction
    processing. Move it to a sensible place.

    Signed-off-by: Avi Kivity <avi@qumranet.com>
    ---
    drivers/kvm/x86_emulate.c | 70 +++++++++++++++++++++++----------------------
    1 files changed, 36 insertions(+), 34 deletions(-)

    diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
    index 84e5366..53377f0 100644
    --- a/drivers/kvm/x86_emulate.c
    +++ b/drivers/kvm/x86_emulate.c
    @@ -64,6 +64,7 @@
    #define Mov (1<<7)
    #define BitOp (1<<8)
    #define MemAbs (1<<9) /* Memory operand is absolute displacement */
    +#define String (1<<10) /* String instruction (rep capable) */

    static u16 opcode_table[256] = {
    /* 0x00 - 0x07 */
    @@ -133,12 +134,12 @@ static u16 opcode_table[256] = {
    /* 0xA0 - 0xA7 */
    ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
    ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
    - ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
    - ByteOp | ImplicitOps, ImplicitOps,
    + ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
    + ByteOp | ImplicitOps | String, ImplicitOps | String,
    /* 0xA8 - 0xAF */
    - 0, 0, ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
    - ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
    - ByteOp | ImplicitOps, ImplicitOps,
    + 0, 0, ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
    + ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
    + ByteOp | ImplicitOps | String, ImplicitOps | String,
    /* 0xB0 - 0xBF */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* 0xC0 - 0xC7 */
    @@ -1228,6 +1229,36 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
    if (((c->d & ModRM) && (c->modrm_mod != 3)) || (c->d & MemAbs))
    memop = c->modrm_ea;

    + if (c->rep_prefix && (c->d & String)) {
    + /* All REP prefixes have the same first termination condition */
    + if (c->regs[VCPU_REGS_RCX] == 0) {
    + ctxt->vcpu->rip = c->eip;
    + goto done;
    + }
    + /* The second termination condition only applies for REPE
    + * and REPNE. Test if the repeat string operation prefix is
    + * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
    + * corresponding termination condition according to:
    + * - if REPE/REPZ and ZF = 0 then done
    + * - if REPNE/REPNZ and ZF = 1 then done
    + */
    + if ((c->b == 0xa6) || (c->b == 0xa7) ||
    + (c->b == 0xae) || (c->b == 0xaf)) {
    + if ((c->rep_prefix == REPE_PREFIX) &&
    + ((ctxt->eflags & EFLG_ZF) == 0)) {
    + ctxt->vcpu->rip = c->eip;
    + goto done;
    + }
    + if ((c->rep_prefix == REPNE_PREFIX) &&
    + ((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {
    + ctxt->vcpu->rip = c->eip;
    + goto done;
    + }
    + }
    + c->regs[VCPU_REGS_RCX]--;
    + c->eip = ctxt->vcpu->rip;
    + }
    +
    if (c->src.type == OP_MEM) {
    c->src.ptr = (unsigned long *)memop;
    c->src.val = 0;
    @@ -1534,35 +1565,6 @@ special_insn:
    c->dst.type = OP_NONE; /* Disable writeback. */
    break;
    }
    - if (c->rep_prefix) {
    - /* All REP prefixes have the same first termination condition */
    - if (c->regs[VCPU_REGS_RCX] == 0) {
    - ctxt->vcpu->rip = c->eip;
    - goto done;
    - }
    - /* The second termination condition only applies for REPE
    - * and REPNE. Test if the repeat string operation prefix is
    - * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
    - * corresponding termination condition according to:
    - * - if REPE/REPZ and ZF = 0 then done
    - * - if REPNE/REPNZ and ZF = 1 then done
    - */
    - if ((c->b == 0xa6) || (c->b == 0xa7) ||
    - (c->b == 0xae) || (c->b == 0xaf)) {
    - if ((c->rep_prefix == REPE_PREFIX) &&
    - ((ctxt->eflags & EFLG_ZF) == 0)) {
    - ctxt->vcpu->rip = c->eip;
    - goto done;
    - }
    - if ((c->rep_prefix == REPNE_PREFIX) &&
    - ((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {
    - ctxt->vcpu->rip = c->eip;
    - goto done;
    - }
    - }
    - c->regs[VCPU_REGS_RCX]--;
    - c->eip = ctxt->vcpu->rip;
    - }
    switch (c->b) {
    case 0xa4 ... 0xa5: /* movs */
    c->dst.type = OP_MEM;
    --
    1.5.3.7


    \
     
     \ /
      Last update: 2008-01-01 16:45    [W:4.142 / U:0.104 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site