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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 B62FDC433E6 for ; Fri, 28 Aug 2020 15:36:08 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 7E91520825 for ; Fri, 28 Aug 2020 15:36:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="By3uLvTL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E91520825 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Q55CquOVqLokda+lnCV9i4TmIqvIO2Yeeo9IwgGLLYQ=; b=By3uLvTLcby7+oRox+EpesPsD XXOAtSHsB7GvdYnP3N8CAbHxWPDBmB34q32pE6AI1pIo0Wm7WADXDKgouZbhnA4qSxvmnu6P2lfX0 OO0JFxdRrfn00SFUum1csveTKkRKEgBskELNUDq/Xofgqj+A1nKTi438HKlAZohalPbzpwudtrm7+ GiFL9zZu1t/u8iYmv/3PKRxKs41r1NvyTlza0TnWzQG2a/WlUMi8ZI/jA5jz3P4Pn9dSWH7hV9W3d o6am4uhrOA0HM8lZPrCPK3UIi8dTxTMHdSIkPzcnK66zi6Xg+1UzWaqgeIXhqwzAP9+mMEZhCFrXd CEb03QG/w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kBgOh-0003H1-DF; Fri, 28 Aug 2020 15:34:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kBgOe-0003Gb-BT for linux-arm-kernel@lists.infradead.org; Fri, 28 Aug 2020 15:34:33 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 45B9931B; Fri, 28 Aug 2020 08:34:30 -0700 (PDT) Received: from [192.168.0.110] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 750213F71F; Fri, 28 Aug 2020 08:34:29 -0700 (PDT) Subject: Re: [PATCH v3 03/21] KVM: arm64: Add support for creating kernel-agnostic stage-1 page tables To: Will Deacon , kvmarm@lists.cs.columbia.edu References: <20200825093953.26493-1-will@kernel.org> <20200825093953.26493-4-will@kernel.org> From: Alexandru Elisei Message-ID: <57e40fa8-f6e3-d442-3bd4-412f04d88a4b@arm.com> Date: Fri, 28 Aug 2020 16:35:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200825093953.26493-4-will@kernel.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200828_113432_565051_D9472048 X-CRM114-Status: GOOD ( 30.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marc Zyngier , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, Catalin Marinas 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 Hi Will, On 8/25/20 10:39 AM, Will Deacon wrote: > The generic page-table walker is pretty useless as it stands, because it > doesn't understand enough to allocate anything. Teach it about stage-1 > page-tables, and hook up an API for allocating these for the hypervisor > at EL2. > > Cc: Marc Zyngier > Cc: Quentin Perret > Signed-off-by: Will Deacon > --- > arch/arm64/include/asm/kvm_pgtable.h | 34 +++++++ > arch/arm64/kvm/hyp/pgtable.c | 131 +++++++++++++++++++++++++++ > 2 files changed, 165 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h > index 51ccbbb0efae..ec9f98527dcc 100644 > --- a/arch/arm64/include/asm/kvm_pgtable.h > +++ b/arch/arm64/include/asm/kvm_pgtable.h > @@ -77,6 +77,40 @@ struct kvm_pgtable_walker { > const enum kvm_pgtable_walk_flags flags; > }; > > +/** > + * kvm_pgtable_hyp_init() - Initialise a hypervisor stage-1 page-table. > + * @pgt: Uninitialised page-table structure to initialise. > + * @va_bits: Maximum virtual address bits. > + * > + * Return: 0 on success, negative error code on failure. > + */ > +int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits); > + > +/** > + * kvm_pgtable_hyp_destroy() - Destroy an unused hypervisor stage-1 page-table. > + * @pgt: Page-table structure initialised by kvm_pgtable_hyp_init(). > + * > + * The page-table is assumed to be unreachable by any hardware walkers prior > + * to freeing and therefore no TLB invalidation is performed. > + */ > +void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt); > + > +/** > + * kvm_pgtable_hyp_map() - Install a mapping in a hypervisor stage-1 page-table. > + * @pgt: Page-table structure initialised by kvm_pgtable_hyp_init(). > + * @addr: Virtual address at which to place the mapping. > + * @size: Size of the mapping. > + * @phys: Physical address of the memory to map. > + * @prot: Permissions and attributes for the mapping. > + * > + * If device attributes are not explicitly requested in @prot, then the > + * mapping will be normal, cacheable. > + * > + * Return: 0 on success, negative error code on failure. >From my understanding of the code, when the caller replaces an existing leaf entry or a table with a different one, KVM will print a warning instead of using break-before-make (if necessary). It might be worth pointing out that it is expected from the callers not to do that, because it's not immediately obvious. > + */ > +int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys, > + enum kvm_pgtable_prot prot); > + > /** > * kvm_pgtable_walk() - Walk a page-table. > * @pgt: Page-table structure initialised by kvm_pgtable_*_init(). > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index 462001bbe028..d75166823ad9 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -24,8 +24,18 @@ > > #define KVM_PTE_LEAF_ATTR_LO GENMASK(11, 2) > > +#define KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX GENMASK(4, 2) > +#define KVM_PTE_LEAF_ATTR_LO_S1_AP GENMASK(7, 6) > +#define KVM_PTE_LEAF_ATTR_LO_S1_AP_RO 3 > +#define KVM_PTE_LEAF_ATTR_LO_S1_AP_RW 1 > +#define KVM_PTE_LEAF_ATTR_LO_S1_SH GENMASK(9, 8) > +#define KVM_PTE_LEAF_ATTR_LO_S1_SH_IS 3 > +#define KVM_PTE_LEAF_ATTR_LO_S1_AF BIT(10) > + > #define KVM_PTE_LEAF_ATTR_HI GENMASK(63, 51) > > +#define KVM_PTE_LEAF_ATTR_HI_S1_XN BIT(54) I compared the macros to the Arm ARM attribute fields in stage 1 VMSAv8-64 block and page descriptors, and they match. I looked at the algorithm below, and for what it's worth it looks alright to me. Thanks, Alex > + > struct kvm_pgtable_walk_data { > struct kvm_pgtable *pgt; > struct kvm_pgtable_walker *walker; > @@ -288,3 +298,124 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, > > return _kvm_pgtable_walk(&walk_data); > } > + > +struct hyp_map_data { > + u64 phys; > + kvm_pte_t attr; > +}; > + > +static int hyp_map_set_prot_attr(enum kvm_pgtable_prot prot, > + struct hyp_map_data *data) > +{ > + bool device = prot & KVM_PGTABLE_PROT_DEVICE; > + u32 mtype = device ? MT_DEVICE_nGnRE : MT_NORMAL; > + kvm_pte_t attr = FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX, mtype); > + u32 sh = KVM_PTE_LEAF_ATTR_LO_S1_SH_IS; > + u32 ap = (prot & KVM_PGTABLE_PROT_W) ? KVM_PTE_LEAF_ATTR_LO_S1_AP_RW : > + KVM_PTE_LEAF_ATTR_LO_S1_AP_RO; > + > + if (!(prot & KVM_PGTABLE_PROT_R)) > + return -EINVAL; > + > + if (prot & KVM_PGTABLE_PROT_X) { > + if (prot & KVM_PGTABLE_PROT_W) > + return -EINVAL; > + > + if (device) > + return -EINVAL; > + } else { > + attr |= KVM_PTE_LEAF_ATTR_HI_S1_XN; > + } > + > + attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_AP, ap); > + attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_SH, sh); > + attr |= KVM_PTE_LEAF_ATTR_LO_S1_AF; > + data->attr = attr; > + return 0; > +} > + > +static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level, > + kvm_pte_t *ptep, struct hyp_map_data *data) > +{ > + u64 granule = kvm_granule_size(level), phys = data->phys; > + > + if (!kvm_block_mapping_supported(addr, end, phys, level)) > + return false; > + > + WARN_ON(!kvm_set_valid_leaf_pte(ptep, phys, data->attr, level)); > + data->phys += granule; > + return true; > +} > + > +static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, > + enum kvm_pgtable_walk_flags flag, void * const arg) > +{ > + kvm_pte_t *childp; > + > + if (hyp_map_walker_try_leaf(addr, end, level, ptep, arg)) > + return 0; > + > + if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1)) > + return -EINVAL; > + > + childp = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL); > + if (!childp) > + return -ENOMEM; > + > + kvm_set_table_pte(ptep, childp); > + return 0; > +} > + > +int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys, > + enum kvm_pgtable_prot prot) > +{ > + int ret; > + struct hyp_map_data map_data = { > + .phys = ALIGN_DOWN(phys, PAGE_SIZE), > + }; > + struct kvm_pgtable_walker walker = { > + .cb = hyp_map_walker, > + .flags = KVM_PGTABLE_WALK_LEAF, > + .arg = &map_data, > + }; > + > + ret = hyp_map_set_prot_attr(prot, &map_data); > + if (ret) > + return ret; > + > + ret = kvm_pgtable_walk(pgt, addr, size, &walker); > + dsb(ishst); > + isb(); > + return ret; > +} > + > +int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits) > +{ > + pgt->pgd = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL); > + if (!pgt->pgd) > + return -ENOMEM; > + > + pgt->ia_bits = va_bits; > + pgt->start_level = kvm_start_level(va_bits); > + pgt->mmu = NULL; > + return 0; > +} > + > +static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, > + enum kvm_pgtable_walk_flags flag, void * const arg) > +{ > + free_page((unsigned long)kvm_pte_follow(*ptep)); > + return 0; > +} > + > +void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt) > +{ > + struct kvm_pgtable_walker walker = { > + .cb = hyp_free_walker, > + .flags = KVM_PGTABLE_WALK_TABLE_POST, > + }; > + > + WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker)); > + free_page((unsigned long)pgt->pgd); > + pgt->pgd = NULL; > +} _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel