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Tue, 20 Jul 2021 08:49:49 -0700 (PDT) Received: from google.com ([2a00:79e0:d:210:ffa2:b757:e72a:11dd]) by smtp.gmail.com with ESMTPSA id c2sm23910164wrs.60.2021.07.20.08.49.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Jul 2021 08:49:48 -0700 (PDT) Date: Tue, 20 Jul 2021 16:49:45 +0100 From: Quentin Perret To: Marc Zyngier Subject: Re: [PATCH 04/16] KVM: arm64: Add MMIO checking infrastructure Message-ID: References: <20210715163159.1480168-1-maz@kernel.org> <20210715163159.1480168-5-maz@kernel.org> <87wnpl86sz.wl-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87wnpl86sz.wl-maz@kernel.org> Cc: kernel-team@android.com, kvm@vger.kernel.org, Srivatsa Vaddagiri , linux-kernel@vger.kernel.org, Shanker R Donthineni , will@kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Tuesday 20 Jul 2021 at 14:15:56 (+0100), Marc Zyngier wrote: > On Tue, 20 Jul 2021 12:13:20 +0100, > Quentin Perret wrote: > > > > On Thursday 15 Jul 2021 at 17:31:47 (+0100), Marc Zyngier wrote: > > > +struct s2_walk_data { > > > + kvm_pte_t pteval; > > > + u32 level; > > > +}; > > > + > > > +static int s2_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, > > > + enum kvm_pgtable_walk_flags flag, void * const arg) > > > +{ > > > + struct s2_walk_data *data = arg; > > > + > > > + data->level = level; > > > + data->pteval = *ptep; > > > + return 0; > > > +} > > > + > > > +/* Assumes mmu_lock taken */ > > > +static bool __check_ioguard_page(struct kvm_vcpu *vcpu, gpa_t ipa) > > > +{ > > > + struct s2_walk_data data; > > > + struct kvm_pgtable_walker walker = { > > > + .cb = s2_walker, > > > + .flags = KVM_PGTABLE_WALK_LEAF, > > > + .arg = &data, > > > + }; > > > + > > > + kvm_pgtable_walk(vcpu->arch.hw_mmu->pgt, ALIGN_DOWN(ipa, PAGE_SIZE), > > > + PAGE_SIZE, &walker); > > > + > > > + /* Must be a PAGE_SIZE mapping with our annotation */ > > > + return (BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(data.level)) == PAGE_SIZE && > > > + data.pteval == MMIO_NOTE); > > > > Nit: you could do this check in the walker directly and check the return > > value of kvm_pgtable_walk() instead. That would allow to get rid of > > struct s2_walk_data. > > > > Also, though the compiler might be able to optimize, maybe simplify the > > level check to level == (KVM_PGTABLE_MAX_LEVELS - 1)? > > Yup, all good points. I guess I could do the same in my other series > that parses the userspace PT to extract the level. Well, actually, let me take that back. I think something like you have would be useful, but in pgtable.c directly and re-usable for stage-1 and stage-2 walks. Maybe something like the below (totally untested)? I could use such a walker in several places as well in the memory ownership series: - following the idea of [1], I could remove the kvm_pgtable_stage2_find_range() function entirely; - [2] defines 2 custom walkers that do nothing but walk host stage-2 and hyp stage-1 page-tables to check permissions and such -- they could be removed/re-implemented easily as well. And you seem to need something similar here, so clearly there is a need. WDYT? Thanks, Quentin [1] https://lore.kernel.org/kvmarm/20210719104735.3681732-3-qperret@google.com/ [2] https://lore.kernel.org/kvmarm/20210719104735.3681732-14-qperret@google.com/ diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index e0ae57dca827..bd6d26f27e1a 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -357,6 +357,38 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, return _kvm_pgtable_walk(&walk_data); } +struct get_leaf_data { + kvm_pte_t *ptep; + u32 *level; +}; + +static int get_leaf_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, void * const arg) +{ + struct get_leaf_data *data = arg; + + *(data->ptep) = *ptep; + *(data->level) = level; + + return 0; +} + +int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr, kvm_pte_t *ptep, + u32 *level) +{ + struct get_leaf_data data = { + .ptep = ptep, + .level = level, + }; + struct kvm_pgtable_walker __get_leaf_walker = { + .cb = get_leaf_walker, + .flags = KVM_PGTABLE_WALK_LEAF, + .arg = &data, + }; + + return kvm_pgtable_walk(pgt, addr, PAGE_SIZE, &__get_leaf_walker); +} + struct hyp_map_data { u64 phys; kvm_pte_t attr; _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,FSL_HELO_FAKE, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61E7EC07E95 for ; Tue, 20 Jul 2021 15:51:38 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2789D60FED for ; 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Tue, 20 Jul 2021 08:49:48 -0700 (PDT) Date: Tue, 20 Jul 2021 16:49:45 +0100 From: Quentin Perret To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, will@kernel.org, dbrazdil@google.com, Srivatsa Vaddagiri , Shanker R Donthineni , James Morse , Suzuki K Poulose , Alexandru Elisei , kernel-team@android.com Subject: Re: [PATCH 04/16] KVM: arm64: Add MMIO checking infrastructure Message-ID: References: <20210715163159.1480168-1-maz@kernel.org> <20210715163159.1480168-5-maz@kernel.org> <87wnpl86sz.wl-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87wnpl86sz.wl-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210720_084951_046763_235B3331 X-CRM114-Status: GOOD ( 23.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tuesday 20 Jul 2021 at 14:15:56 (+0100), Marc Zyngier wrote: > On Tue, 20 Jul 2021 12:13:20 +0100, > Quentin Perret wrote: > > > > On Thursday 15 Jul 2021 at 17:31:47 (+0100), Marc Zyngier wrote: > > > +struct s2_walk_data { > > > + kvm_pte_t pteval; > > > + u32 level; > > > +}; > > > + > > > +static int s2_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, > > > + enum kvm_pgtable_walk_flags flag, void * const arg) > > > +{ > > > + struct s2_walk_data *data = arg; > > > + > > > + data->level = level; > > > + data->pteval = *ptep; > > > + return 0; > > > +} > > > + > > > +/* Assumes mmu_lock taken */ > > > +static bool __check_ioguard_page(struct kvm_vcpu *vcpu, gpa_t ipa) > > > +{ > > > + struct s2_walk_data data; > > > + struct kvm_pgtable_walker walker = { > > > + .cb = s2_walker, > > > + .flags = KVM_PGTABLE_WALK_LEAF, > > > + .arg = &data, > > > + }; > > > + > > > + kvm_pgtable_walk(vcpu->arch.hw_mmu->pgt, ALIGN_DOWN(ipa, PAGE_SIZE), > > > + PAGE_SIZE, &walker); > > > + > > > + /* Must be a PAGE_SIZE mapping with our annotation */ > > > + return (BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(data.level)) == PAGE_SIZE && > > > + data.pteval == MMIO_NOTE); > > > > Nit: you could do this check in the walker directly and check the return > > value of kvm_pgtable_walk() instead. That would allow to get rid of > > struct s2_walk_data. > > > > Also, though the compiler might be able to optimize, maybe simplify the > > level check to level == (KVM_PGTABLE_MAX_LEVELS - 1)? > > Yup, all good points. I guess I could do the same in my other series > that parses the userspace PT to extract the level. Well, actually, let me take that back. I think something like you have would be useful, but in pgtable.c directly and re-usable for stage-1 and stage-2 walks. Maybe something like the below (totally untested)? I could use such a walker in several places as well in the memory ownership series: - following the idea of [1], I could remove the kvm_pgtable_stage2_find_range() function entirely; - [2] defines 2 custom walkers that do nothing but walk host stage-2 and hyp stage-1 page-tables to check permissions and such -- they could be removed/re-implemented easily as well. And you seem to need something similar here, so clearly there is a need. WDYT? Thanks, Quentin [1] https://lore.kernel.org/kvmarm/20210719104735.3681732-3-qperret@google.com/ [2] https://lore.kernel.org/kvmarm/20210719104735.3681732-14-qperret@google.com/ diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index e0ae57dca827..bd6d26f27e1a 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -357,6 +357,38 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, return _kvm_pgtable_walk(&walk_data); } +struct get_leaf_data { + kvm_pte_t *ptep; + u32 *level; +}; + +static int get_leaf_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, void * const arg) +{ + struct get_leaf_data *data = arg; + + *(data->ptep) = *ptep; + *(data->level) = level; + + return 0; +} + +int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr, kvm_pte_t *ptep, + u32 *level) +{ + struct get_leaf_data data = { + .ptep = ptep, + .level = level, + }; + struct kvm_pgtable_walker __get_leaf_walker = { + .cb = get_leaf_walker, + .flags = KVM_PGTABLE_WALK_LEAF, + .arg = &data, + }; + + return kvm_pgtable_walk(pgt, addr, PAGE_SIZE, &__get_leaf_walker); +} + struct hyp_map_data { u64 phys; kvm_pte_t attr; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43B81C07E95 for ; Tue, 20 Jul 2021 16:05:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1BFE56100C for ; 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Tue, 20 Jul 2021 08:49:48 -0700 (PDT) Date: Tue, 20 Jul 2021 16:49:45 +0100 From: Quentin Perret To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, will@kernel.org, dbrazdil@google.com, Srivatsa Vaddagiri , Shanker R Donthineni , James Morse , Suzuki K Poulose , Alexandru Elisei , kernel-team@android.com Subject: Re: [PATCH 04/16] KVM: arm64: Add MMIO checking infrastructure Message-ID: References: <20210715163159.1480168-1-maz@kernel.org> <20210715163159.1480168-5-maz@kernel.org> <87wnpl86sz.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87wnpl86sz.wl-maz@kernel.org> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tuesday 20 Jul 2021 at 14:15:56 (+0100), Marc Zyngier wrote: > On Tue, 20 Jul 2021 12:13:20 +0100, > Quentin Perret wrote: > > > > On Thursday 15 Jul 2021 at 17:31:47 (+0100), Marc Zyngier wrote: > > > +struct s2_walk_data { > > > + kvm_pte_t pteval; > > > + u32 level; > > > +}; > > > + > > > +static int s2_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, > > > + enum kvm_pgtable_walk_flags flag, void * const arg) > > > +{ > > > + struct s2_walk_data *data = arg; > > > + > > > + data->level = level; > > > + data->pteval = *ptep; > > > + return 0; > > > +} > > > + > > > +/* Assumes mmu_lock taken */ > > > +static bool __check_ioguard_page(struct kvm_vcpu *vcpu, gpa_t ipa) > > > +{ > > > + struct s2_walk_data data; > > > + struct kvm_pgtable_walker walker = { > > > + .cb = s2_walker, > > > + .flags = KVM_PGTABLE_WALK_LEAF, > > > + .arg = &data, > > > + }; > > > + > > > + kvm_pgtable_walk(vcpu->arch.hw_mmu->pgt, ALIGN_DOWN(ipa, PAGE_SIZE), > > > + PAGE_SIZE, &walker); > > > + > > > + /* Must be a PAGE_SIZE mapping with our annotation */ > > > + return (BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(data.level)) == PAGE_SIZE && > > > + data.pteval == MMIO_NOTE); > > > > Nit: you could do this check in the walker directly and check the return > > value of kvm_pgtable_walk() instead. That would allow to get rid of > > struct s2_walk_data. > > > > Also, though the compiler might be able to optimize, maybe simplify the > > level check to level == (KVM_PGTABLE_MAX_LEVELS - 1)? > > Yup, all good points. I guess I could do the same in my other series > that parses the userspace PT to extract the level. Well, actually, let me take that back. I think something like you have would be useful, but in pgtable.c directly and re-usable for stage-1 and stage-2 walks. Maybe something like the below (totally untested)? I could use such a walker in several places as well in the memory ownership series: - following the idea of [1], I could remove the kvm_pgtable_stage2_find_range() function entirely; - [2] defines 2 custom walkers that do nothing but walk host stage-2 and hyp stage-1 page-tables to check permissions and such -- they could be removed/re-implemented easily as well. And you seem to need something similar here, so clearly there is a need. WDYT? Thanks, Quentin [1] https://lore.kernel.org/kvmarm/20210719104735.3681732-3-qperret@google.com/ [2] https://lore.kernel.org/kvmarm/20210719104735.3681732-14-qperret@google.com/ diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index e0ae57dca827..bd6d26f27e1a 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -357,6 +357,38 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, return _kvm_pgtable_walk(&walk_data); } +struct get_leaf_data { + kvm_pte_t *ptep; + u32 *level; +}; + +static int get_leaf_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, void * const arg) +{ + struct get_leaf_data *data = arg; + + *(data->ptep) = *ptep; + *(data->level) = level; + + return 0; +} + +int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr, kvm_pte_t *ptep, + u32 *level) +{ + struct get_leaf_data data = { + .ptep = ptep, + .level = level, + }; + struct kvm_pgtable_walker __get_leaf_walker = { + .cb = get_leaf_walker, + .flags = KVM_PGTABLE_WALK_LEAF, + .arg = &data, + }; + + return kvm_pgtable_walk(pgt, addr, PAGE_SIZE, &__get_leaf_walker); +} + struct hyp_map_data { u64 phys; kvm_pte_t attr;