From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752118AbdJFP3Q (ORCPT ); Fri, 6 Oct 2017 11:29:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45840 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751942AbdJFP3N (ORCPT ); Fri, 6 Oct 2017 11:29:13 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 0E701285C1 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eric.auger@redhat.com Subject: Re: [PATCH v2 05/10] KVM: arm/arm64: vgic-its: Check GITS_CBASER validity before processing commands To: Andre Przywara , eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, marc.zyngier@arm.com, cdall@linaro.org, peter.maydell@linaro.org, wanghaibin.wang@huawei.com References: <1506518920-18571-1-git-send-email-eric.auger@redhat.com> <1506518920-18571-6-git-send-email-eric.auger@redhat.com> <44a357a8-6ef2-4fd3-597d-3efd28317056@arm.com> Cc: wu.wubin@huawei.com From: Auger Eric Message-ID: Date: Fri, 6 Oct 2017 17:29:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <44a357a8-6ef2-4fd3-597d-3efd28317056@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 06 Oct 2017 15:29:13 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andre, On 06/10/2017 16:38, Andre Przywara wrote: > Hi, > > On 27/09/17 14:28, Eric Auger wrote: >> At the moment vgic_its_process_commands() does not >> check the CBASER is valid before processing any command. >> Let's fix that. > > Good catch, but actually it goes a bit further: > > "When GITS_CTLR.Enabled is written from 0 to 1 behavior is UNPREDICTABLE > if any of the following conditions are true: > ยท GITS_CBASER.Valid == 0. > ... > " > > So I think we need to check it upon setting CTLR.Enabled. > I did this in Xen, but forgot to fix this in KVM as well: > https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/arch/arm/vgic-v3-its.c;hb=HEAD#l1164 OK. I will add this check. Thanks Eric > > Cheers, > Andre. > >> >> Also rename cbaser local variable into cbaser_pa to avoid >> any confusion with the full register. >> >> Signed-off-by: Eric Auger >> --- >> virt/kvm/arm/vgic/vgic-its.c | 13 ++++++++----- >> 1 file changed, 8 insertions(+), 5 deletions(-) >> >> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c >> index 60ecf91..720552c 100644 >> --- a/virt/kvm/arm/vgic/vgic-its.c >> +++ b/virt/kvm/arm/vgic/vgic-its.c >> @@ -1301,17 +1301,20 @@ static void vgic_mmio_write_its_cbaser(struct kvm *kvm, struct vgic_its *its, >> /* Must be called with the cmd_lock held. */ >> static void vgic_its_process_commands(struct kvm *kvm, struct vgic_its *its) >> { >> - gpa_t cbaser; >> + gpa_t cbaser_pa; >> u64 cmd_buf[4]; >> >> - /* Commands are only processed when the ITS is enabled. */ >> - if (!its->enabled) >> + /* >> + * Commands are only processed when the ITS is enabled and >> + * CBASER is valid >> + */ >> + if (!its->enabled || (!(its->cbaser & GITS_CBASER_VALID))) >> return; >> >> - cbaser = CBASER_ADDRESS(its->cbaser); >> + cbaser_pa = CBASER_ADDRESS(its->cbaser); >> >> while (its->cwriter != its->creadr) { >> - int ret = kvm_read_guest(kvm, cbaser + its->creadr, >> + int ret = kvm_read_guest(kvm, cbaser_pa + its->creadr, >> cmd_buf, ITS_CMD_SIZE); >> /* >> * If kvm_read_guest() fails, this could be due to the guest >>