From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758383AbdJMP0y (ORCPT ); Fri, 13 Oct 2017 11:26:54 -0400 Received: from mail-wm0-f50.google.com ([74.125.82.50]:45639 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753481AbdJMP0x (ORCPT ); Fri, 13 Oct 2017 11:26:53 -0400 X-Google-Smtp-Source: AOwi7QCV/P0ckn4nksp0Z66z4/N1qHoWbt+MOJpSYCzohut3Eqbi1BPRVattp/qo4cxtBL/TLFPINg== Date: Fri, 13 Oct 2017 17:26:58 +0200 From: Christoffer Dall To: Eric Auger Cc: eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, marc.zyngier@arm.com, peter.maydell@linaro.org, andre.przywara@arm.com, wanghaibin.wang@huawei.com, wu.wubin@huawei.com Subject: Re: [PATCH v2 09/10] KVM: arm/arm64: Document KVM_DEV_ARM_ITS_CTRL_RESET Message-ID: <20171013152658.GL8927@cbox> References: <1506518920-18571-1-git-send-email-eric.auger@redhat.com> <1506518920-18571-10-git-send-email-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1506518920-18571-10-git-send-email-eric.auger@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eric, On Wed, Sep 27, 2017 at 03:28:39PM +0200, Eric Auger wrote: > At the moment, the in-kernel emulated ITS is not properly reset. > On guest restart/reset some registers keep their old values and > internal structures like device, ITE, collection lists are not freed. , and collection ... > > This may lead to various bugs. Among them, we can have incorrect state > backup or failure when saving the ITS state at early guest boot stage. > > This patch documents a new attribute, KVM_DEV_ARM_ITS_CTRL_RESET in > the KVM_DEV_ARM_VGIC_GRP_CTRL group. > > Upon this action, we can reset registers and especially those > pointing to tables previously allocated by the guest and free > the internal data structures storing the list of devices, collections > and lpis. > > Signed-off-by: Eric Auger > Reported-by: wanghaibin > > --- > > v1 -> v2: > - Describe architecturally-defined reset values > --- > Documentation/virtual/kvm/devices/arm-vgic-its.txt | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/Documentation/virtual/kvm/devices/arm-vgic-its.txt b/Documentation/virtual/kvm/devices/arm-vgic-its.txt > index eb06beb..047358c 100644 > --- a/Documentation/virtual/kvm/devices/arm-vgic-its.txt > +++ b/Documentation/virtual/kvm/devices/arm-vgic-its.txt > @@ -33,6 +33,10 @@ Groups: > request the initialization of the ITS, no additional parameter in > kvm_device_attr.addr. > > + KVM_DEV_ARM_ITS_CTRL_RESET > + reset the ITS, no additional parameter in kvm_device_attr.addr. > + See "ITS Reset State" section. > + > KVM_DEV_ARM_ITS_SAVE_TABLES > save the ITS table data into guest RAM, at the location provisioned > by the guest in corresponding registers/table entries. > @@ -157,3 +161,15 @@ Then vcpus can be started. > - pINTID is the physical LPI ID; if zero, it means the entry is not valid > and other fields are not meaningful. > - ICID is the collection ID > + > + ITS Reset State: > + ---------------- Are the bullet points below the state after the device has been reset (after KVM_DEV_ARM_ITS_CTRL_RESET returns) or ? I think this should be clarified. > + > +- the ITS is not enabled and quiescent: The > + GITS_CTLR.Enabled = 0 .Quiescent=1 > +- caches are empty Caches (would it make more sense to say that there is no internally cached state?) > +- No collection or device table is provisionned are used: > + GITS_BASER.Valid = 0 > +- the command queue is not allocated: The > + GITS_CBASER = 0, GITS_CREADR = 0, GITS_CWRITER = 0 > +- The ABI version corresponds to the one set before reset Do you mean that resetting the ITS cannot change the ABI version used for save/restore, and therefore remains the same as it the version configured when the device was first created ? > -- > 2.5.5 > Thanks, (and sorry for being pedantic about ABI wordings) -Christoffer