From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v4 04/11] KVM: arm/arm64: vgic-its: Check CBASER/BASER validity before enabling the ITS Date: Wed, 18 Oct 2017 00:02:03 +0200 Message-ID: <20171017220203.GD8326@lvm> References: <1508224209-15366-1-git-send-email-eric.auger@redhat.com> <1508224209-15366-5-git-send-email-eric.auger@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, marc.zyngier@arm.com, peter.maydell@linaro.org, andre.przywara@arm.com, wanghaibin.wang@huawei.com, wu.wubin@huawei.com, drjones@redhat.com, wei@redhat.com To: Eric Auger Return-path: Content-Disposition: inline In-Reply-To: <1508224209-15366-5-git-send-email-eric.auger@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Tue, Oct 17, 2017 at 09:10:02AM +0200, Eric Auger wrote: > The spec says it is UNPREDICTABLE to enable the ITS > if any of the following conditions are true: > > - GITS_CBASER.Valid == 0. > - GITS_BASER.Valid == 0, for any GITS_BASER register > where the Type field indicates Device. > - GITS_BASER.Valid == 0, for any GITS_BASER register > where the Type field indicates Interrupt Collection and > GITS_TYPER.HCC == 0. > > In that case, let's keep the ITS disabled. > > Signed-off-by: Eric Auger > Reported-by: Andre Przywara > > --- > > v3: creation > --- > virt/kvm/arm/vgic/vgic-its.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index e59363e..e61736b 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -1488,6 +1488,16 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its, > its->enabled = !!(val & GITS_CTLR_ENABLE); > > /* > + * It is UNPREDICTABLE to enable the ITS if any of the CBASER or > + * device/collection BASER are invalid > + */ > + if (its->enabled && > + (!(its->baser_device_table & GITS_BASER_VALID) || > + !(its->baser_coll_table & GITS_BASER_VALID) || > + !(its->cbaser && GITS_CBASER_VALID))) > + its->enabled = false; > + uh, why don't we check these conditions before we enable the ITS instead of enabling, checking, and then disabling? Thanks, -Christoffer > + /* > * Try to process any pending commands. This function bails out early > * if the ITS is disabled or no commands have been queued. > */ > -- > 2.5.5 >