From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754028AbeDZHrJ (ORCPT ); Thu, 26 Apr 2018 03:47:09 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:36792 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752018AbeDZHrH (ORCPT ); Thu, 26 Apr 2018 03:47:07 -0400 Subject: Re: [PATCH v3 04/12] KVM: arm/arm64: Helper to locate free rdist index To: Christoffer Dall References: <1523607658-9166-1-git-send-email-eric.auger@redhat.com> <1523607658-9166-5-git-send-email-eric.auger@redhat.com> <20180424210704.GG4533@C02W217FHV2R.local> Cc: eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, marc.zyngier@arm.com, cdall@kernel.org, peter.maydell@linaro.org, andre.przywara@arm.com, drjones@redhat.com, wei@redhat.com From: Auger Eric Message-ID: <40978427-0cf7-3a03-f12e-bde73548180e@redhat.com> Date: Thu, 26 Apr 2018 09:47:00 +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: <20180424210704.GG4533@C02W217FHV2R.local> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christoffer, On 04/24/2018 11:07 PM, Christoffer Dall wrote: > On Fri, Apr 13, 2018 at 10:20:50AM +0200, Eric Auger wrote: >> We introduce vgic_v3_rdist_free_slot to help identifying >> where we can place a new 2x64KB redistributor. >> >> Signed-off-by: Eric Auger >> --- >> virt/kvm/arm/vgic/vgic-mmio-v3.c | 3 +-- >> virt/kvm/arm/vgic/vgic-v3.c | 17 +++++++++++++++++ >> virt/kvm/arm/vgic/vgic.h | 11 +++++++++++ >> 3 files changed, 29 insertions(+), 2 deletions(-) >> >> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c >> index d1aab18..49ca176 100644 >> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c >> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c >> @@ -593,8 +593,7 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu) >> * function for all VCPUs when the base address is set. Just return >> * without doing any work for now. >> */ >> - rdreg = list_first_entry(&vgic->rd_regions, >> - struct vgic_redist_region, list); >> + rdreg = vgic_v3_rdist_free_slot(&vgic->rd_regions); >> if (!rdreg) >> return 0; >> >> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c >> index 94de6cd..820012a 100644 >> --- a/virt/kvm/arm/vgic/vgic-v3.c >> +++ b/virt/kvm/arm/vgic/vgic-v3.c >> @@ -444,6 +444,23 @@ bool vgic_v3_check_base(struct kvm *kvm) >> return false; >> } >> >> +/** >> + * vgic_v3_rdist_free_slot - Look up registered rdist regions and identify one >> + * which has free space to put a new rdist regions > > Can this structure ever be sparse or do we always find the first empty > one, as we fill them consecutively ? We always find the first empty 2x64kB slot within the region (stride between redistributors = 0). Regions are filled in the index order. The only hole that can exist is at the end of the region if its size is not multiple of 2x64kB. > > I assume there is some mapping between the regions and the VCPUs' > redistributors, so perhaps the wording in this comment can be more > precise. changed into: " A redistributor regions maps n redistributors, n = region size / (2 x 64kB). Stride between redistributors is 0 and regions are filled in the index order. " > >> + * >> + * If any, return this redist region handle, otherwise returns NULL. >> + */ >> +struct vgic_redist_region *vgic_v3_rdist_free_slot(struct list_head *rd_regions) >> +{ >> + struct vgic_redist_region *rdreg; >> + >> + list_for_each_entry(rdreg, rd_regions, list) { >> + if (!vgic_v3_redist_region_full(rdreg)) >> + return rdreg; >> + } >> + return NULL; >> +} >> + >> int vgic_v3_map_resources(struct kvm *kvm) >> { >> int ret = 0; >> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h >> index 830e815..fea32cb 100644 >> --- a/virt/kvm/arm/vgic/vgic.h >> +++ b/virt/kvm/arm/vgic/vgic.h >> @@ -251,6 +251,17 @@ static inline int vgic_v3_max_apr_idx(struct kvm_vcpu *vcpu) >> } >> } >> >> +static inline bool >> +vgic_v3_redist_region_full(struct vgic_redist_region *region) >> +{ >> + if (!region->count) >> + return false; >> + >> + return (region->free_index >= region->count); >> +} >> + >> +struct vgic_redist_region *vgic_v3_rdist_free_slot(struct list_head *rdregs); >> + >> int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its, >> u32 devid, u32 eventid, struct vgic_irq **irq); >> struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi); >> -- >> 2.5.5 >> > > Asides from the above: > > Reviewed-by: Christoffer Dall Thanks Eric >