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authorGleb Natapov <gleb@redhat.com>2012-09-03 15:24:29 +0300
committerAvi Kivity <avi@redhat.com>2012-09-06 18:07:38 +0300
commitb3356bf0dbb34980620f2f7def7d1b9a0d325225 (patch)
tree508f58ece4a7ff5613181584fd0461e7cbfd5d20 /arch/x86/kvm
parentf3bd64c68a8f1245e3d037f70c6936cd7bb1196b (diff)
KVM: emulator: optimize "rep ins" handling
Optimize "rep ins" by allowing emulator to write back more than one datum at a time. Introduce new operand type OP_MEM_STR which tells writeback() that dst contains pointer to an array that should be written back as opposite to just one data element. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/emulate.c33
1 files changed, 28 insertions, 5 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 415f903facd3..39171cb307ea 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1301,8 +1301,15 @@ static int pio_in_emulated(struct x86_emulate_ctxt *ctxt,
rc->end = n * size;
}
- memcpy(dest, rc->data + rc->pos, size);
- rc->pos += size;
+ if (ctxt->rep_prefix && !(ctxt->eflags & EFLG_DF)) {
+ ctxt->dst.data = rc->data + rc->pos;
+ ctxt->dst.type = OP_MEM_STR;
+ ctxt->dst.count = (rc->end - rc->pos) / size;
+ rc->pos = rc->end;
+ } else {
+ memcpy(dest, rc->data + rc->pos, size);
+ rc->pos += size;
+ }
return 1;
}
@@ -1546,6 +1553,14 @@ static int writeback(struct x86_emulate_ctxt *ctxt)
if (rc != X86EMUL_CONTINUE)
return rc;
break;
+ case OP_MEM_STR:
+ rc = segmented_write(ctxt,
+ ctxt->dst.addr.mem,
+ ctxt->dst.data,
+ ctxt->dst.bytes * ctxt->dst.count);
+ if (rc != X86EMUL_CONTINUE)
+ return rc;
+ break;
case OP_XMM:
write_sse_reg(ctxt, &ctxt->dst.vec_val, ctxt->dst.addr.xmm);
break;
@@ -2793,7 +2808,7 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
static void string_addr_inc(struct x86_emulate_ctxt *ctxt, int reg,
struct operand *op)
{
- int df = (ctxt->eflags & EFLG_DF) ? -1 : 1;
+ int df = (ctxt->eflags & EFLG_DF) ? -op->count : op->count;
register_address_increment(ctxt, reg_rmw(ctxt, reg), df * op->bytes);
op->addr.mem.ea = register_address(ctxt, reg_read(ctxt, reg));
@@ -3733,7 +3748,7 @@ static const struct opcode opcode_table[256] = {
I(DstReg | SrcMem | ModRM | Src2Imm, em_imul_3op),
I(SrcImmByte | Mov | Stack, em_push),
I(DstReg | SrcMem | ModRM | Src2ImmByte, em_imul_3op),
- I2bvIP(DstDI | SrcDX | Mov | String, em_in, ins, check_perm_in), /* insb, insw/insd */
+ I2bvIP(DstDI | SrcDX | Mov | String | Unaligned, em_in, ins, check_perm_in), /* insb, insw/insd */
I2bvIP(SrcSI | DstDX | String, em_out, outs, check_perm_out), /* outsb, outsw/outsd */
/* 0x70 - 0x7F */
X16(D(SrcImmByte)),
@@ -3991,6 +4006,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
register_address(ctxt, reg_read(ctxt, VCPU_REGS_RDI));
op->addr.mem.seg = VCPU_SREG_ES;
op->val = 0;
+ op->count = 1;
break;
case OpDX:
op->type = OP_REG;
@@ -4034,6 +4050,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
register_address(ctxt, reg_read(ctxt, VCPU_REGS_RSI));
op->addr.mem.seg = seg_override(ctxt);
op->val = 0;
+ op->count = 1;
break;
case OpImmFAddr:
op->type = OP_IMM;
@@ -4575,8 +4592,14 @@ writeback:
string_addr_inc(ctxt, VCPU_REGS_RDI, &ctxt->dst);
if (ctxt->rep_prefix && (ctxt->d & String)) {
+ unsigned int count;
struct read_cache *r = &ctxt->io_read;
- register_address_increment(ctxt, reg_rmw(ctxt, VCPU_REGS_RCX), -1);
+ if ((ctxt->d & SrcMask) == SrcSI)
+ count = ctxt->src.count;
+ else
+ count = ctxt->dst.count;
+ register_address_increment(ctxt, reg_rmw(ctxt, VCPU_REGS_RCX),
+ -count);
if (!string_insn_completed(ctxt)) {
/*