From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH v2 3/3] KVM: x86 emulator: fix REPZ/REPNZ termination condition Date: Thu, 19 Aug 2010 13:55:05 +0300 Message-ID: <20100819105505.GI10499@redhat.com> References: <1282063460-20478-1-git-send-email-avi@redhat.com> <1282063460-20478-4-git-send-email-avi@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:10091 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752652Ab0HSKzH (ORCPT ); Thu, 19 Aug 2010 06:55:07 -0400 Received: from int-mx03.intmail.prod.int.phx2.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o7JAt6TT019804 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 19 Aug 2010 06:55:06 -0400 Content-Disposition: inline In-Reply-To: <1282063460-20478-4-git-send-email-avi@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Aug 17, 2010 at 07:44:20PM +0300, Avi Kivity wrote: > if ((c->src.type == OP_MEM) && !(c->d & NoAccess)) { > @@ -3230,13 +3212,29 @@ writeback: > if (c->rep_prefix && (c->d & String)) { > struct read_cache *rc = &ctxt->decode.io_read; > register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1); > + /* 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)) > + && (((c->rep_prefix == REPE_PREFIX) && > + ((ctxt->eflags & EFLG_ZF) == 0)) > + || ((c->rep_prefix == REPNE_PREFIX) && > + ((ctxt->eflags & EFLG_ZF) == EFLG_ZF)))) > + ctxt->restart = false; > /* > * Re-enter guest when pio read ahead buffer is empty or, > * if it is not used, after each 1024 iteration. > */ > - if ((rc->end == 0 && !(c->regs[VCPU_REGS_RCX] & 0x3ff)) || > - (rc->end != 0 && rc->end == rc->pos)) > + else if ((rc->end == 0 && !(c->regs[VCPU_REGS_RCX] & 0x3ff)) || > + (rc->end != 0 && rc->end == rc->pos)) { > ctxt->restart = false; > + c->eip = ctxt->eip; If io exit to use space is needed we may not get here, so ctxt->eip will be updated to point past instruction in the middle of instruction emulation and that may cause incomplete instruction emulation. > + } > } > /* > * reset read cache here in case string instruction is restared > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb.