From patchwork Mon Mar 15 14:38:55 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gleb Natapov X-Patchwork-Id: 85970 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o2FEen27014674 for ; Mon, 15 Mar 2010 14:40:49 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965029Ab0COOjl (ORCPT ); Mon, 15 Mar 2010 10:39:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46469 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964994Ab0COOjE (ORCPT ); Mon, 15 Mar 2010 10:39:04 -0400 Received: from int-mx04.intmail.prod.int.phx2.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.17]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o2FEd2Ot007709 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 15 Mar 2010 10:39:03 -0400 Received: from dhcp-1-237.tlv.redhat.com (dhcp-1-237.tlv.redhat.com [10.35.1.237]) by int-mx04.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o2FEcx8J006219; Mon, 15 Mar 2010 10:39:01 -0400 Received: by dhcp-1-237.tlv.redhat.com (Postfix, from userid 13519) id DCEDF1339B6; Mon, 15 Mar 2010 16:38:58 +0200 (IST) From: Gleb Natapov To: avi@redhat.com, mtosatti@redhat.com Cc: kvm@vger.kernel.org Subject: [PATCH v3 28/30] KVM: x86 emulator: restart string instruction without going back to a guest. Date: Mon, 15 Mar 2010 16:38:55 +0200 Message-Id: <1268663937-27784-29-git-send-email-gleb@redhat.com> In-Reply-To: <1268663937-27784-1-git-send-email-gleb@redhat.com> References: <1268663937-27784-1-git-send-email-gleb@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.17 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Mon, 15 Mar 2010 14:40:49 +0000 (UTC) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index 679245c..7fda16f 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -193,6 +193,7 @@ struct x86_emulate_ctxt { /* interruptibility state, as a result of execution of STI or MOV SS */ int interruptibility; + bool restart; /* restart string instruction after writeback */ /* decode cache */ struct decode_cache decode; }; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 541f3c9..c4da60e 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); @@ -2422,6 +2425,7 @@ 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; @@ -2450,8 +2454,11 @@ 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; } @@ -2463,17 +2470,13 @@ 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; } @@ -2906,6 +2909,12 @@ 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); @@ -2913,8 +2922,11 @@ 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); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b8237ac..cd0043a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3718,6 +3718,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, return EMULATE_DONE; } +restart: r = x86_emulate_insn(&vcpu->arch.emulate_ctxt, &emulate_ops); shadow_mask = vcpu->arch.emulate_ctxt.interruptibility; @@ -3740,7 +3741,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, if (r) { if (kvm_mmu_unprotect_page_virt(vcpu, cr2)) - return EMULATE_DONE; + goto done; if (!vcpu->mmio_needed) { kvm_report_emulation_failure(vcpu, "mmio"); return EMULATE_FAIL; @@ -3755,6 +3756,13 @@ int emulate_instruction(struct kvm_vcpu *vcpu, return EMULATE_DO_MMIO; } +done: + if (vcpu->arch.exception.pending) + vcpu->arch.emulate_ctxt.restart = false; + + if (vcpu->arch.emulate_ctxt.restart) + goto restart; + return EMULATE_DONE; } EXPORT_SYMBOL_GPL(emulate_instruction); @@ -4523,6 +4531,15 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) goto out; } } + if (vcpu->arch.emulate_ctxt.restart) { + vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + r = emulate_instruction(vcpu, 0, 0, EMULTYPE_NO_DECODE); + srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); + if (r == EMULATE_DO_MMIO) { + r = 0; + goto out; + } + } if (kvm_run->exit_reason == KVM_EXIT_HYPERCALL) kvm_register_write(vcpu, VCPU_REGS_RAX, kvm_run->hypercall.ret);