Commit b3356bf0 authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
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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: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent f3bd64c6
......@@ -213,8 +213,9 @@ typedef u32 __attribute__((vector_size(16))) sse128_t;
/* Type, address-of, and value of an instruction's operand. */
struct operand {
enum { OP_REG, OP_MEM, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
unsigned int bytes;
unsigned int count;
union {
unsigned long orig_val;
u64 orig_val64;
......@@ -234,6 +235,7 @@ struct operand {
char valptr[sizeof(unsigned long) + 2];
sse128_t vec_val;
u64 mm_val;
void *data;
};
};
......
......@@ -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)) {
/*
......
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