diff options
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 34 |
1 files changed, 23 insertions, 11 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 0579d9dd9aac..6de6ad1610d8 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -927,8 +927,11 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) int mode = ctxt->mode; int def_op_bytes, def_ad_bytes, group; - /* Shadow copy of register state. Committed on successful emulation. */ + /* we cannot decode insn before we complete previous rep insn */ + WARN_ON(ctxt->restart); + + /* Shadow copy of register state. Committed on successful emulation. */ memset(c, 0, sizeof(struct decode_cache)); c->eip = ctxt->eip; ctxt->cs_base = seg_base(ctxt, VCPU_SREG_CS); @@ -2426,6 +2429,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) u64 msr_data; struct decode_cache *c = &ctxt->decode; int rc = X86EMUL_CONTINUE; + int saved_dst_type = c->dst.type; ctxt->interruptibility = 0; @@ -2454,8 +2458,11 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) } if (c->rep_prefix && (c->d & String)) { + ctxt->restart = true; /* All REP prefixes have the same first termination condition */ if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) { + string_done: + ctxt->restart = false; kvm_rip_write(ctxt->vcpu, c->eip); goto done; } @@ -2467,17 +2474,13 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) * - if REPNE/REPNZ and ZF = 1 then done */ if ((c->b == 0xa6) || (c->b == 0xa7) || - (c->b == 0xae) || (c->b == 0xaf)) { + (c->b == 0xae) || (c->b == 0xaf)) { if ((c->rep_prefix == REPE_PREFIX) && - ((ctxt->eflags & EFLG_ZF) == 0)) { - kvm_rip_write(ctxt->vcpu, c->eip); - goto done; - } + ((ctxt->eflags & EFLG_ZF) == 0)) + goto string_done; if ((c->rep_prefix == REPNE_PREFIX) && - ((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) { - kvm_rip_write(ctxt->vcpu, c->eip); - goto done; - } + ((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) + goto string_done; } c->eip = ctxt->eip; } @@ -2911,6 +2914,12 @@ writeback: if (rc != X86EMUL_CONTINUE) goto done; + /* + * restore dst type in case the decoding will be reused + * (happens for string instruction ) + */ + c->dst.type = saved_dst_type; + if ((c->d & SrcMask) == SrcSI) string_addr_inc(ctxt, seg_override_base(ctxt, c), VCPU_REGS_RSI, &c->src); @@ -2918,8 +2927,11 @@ writeback: if ((c->d & DstMask) == DstDI) string_addr_inc(ctxt, es_base(ctxt), VCPU_REGS_RDI, &c->dst); - if (c->rep_prefix && (c->d & String)) + if (c->rep_prefix && (c->d & String)) { register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1); + if (!(c->regs[VCPU_REGS_RCX] & 0x3ff)) + ctxt->restart = false; + } /* Commit shadow register state. */ memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs); |