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=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 BAB34C433E6 for ; Mon, 1 Feb 2021 18:34:15 +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 674B164E3C for ; Mon, 1 Feb 2021 18:34:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 674B164E3C Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.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:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XIquBYVXRQBPAB2MBIF7gFk5mL/fnKShT/yOiHVdWpw=; b=zHmB3earxnRiO5hunnf+ptpkh 0QpLHxP1O87C+EYaVOIZLfrinQyZWPy/Gbksy1o90itiR8B5cJQLDtv8aIGX9oPyMWOizwmVIFgtd j06tuD1tlo+BzuSf1QE6tgHv0XDOZh4w9NbObhl8GPpfEho7SY4OBAsrzqWC42sr9324eSS0OOzMP IuKsSjjWhUrAoMrq3QqQ+Lpp9SpO/og71E/3fPRHqINsIPHZkk/krbDBtTokwT3ZXTH1LgeD3a9Ln fbj4AjiYyaWY2OepB++agSUmr9iuiLMLxDpGHPuwRGiFgcoILFysLP0u1wuxdN4eCBwond1PdBE2y /EpOZj8qw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6e0T-00016d-Vt; Mon, 01 Feb 2021 18:33:02 +0000 Received: from mail-wm1-x32f.google.com ([2a00:1450:4864:20::32f]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6e0P-00015A-6K for linux-arm-kernel@lists.infradead.org; Mon, 01 Feb 2021 18:32:59 +0000 Received: by mail-wm1-x32f.google.com with SMTP id o10so450476wmc.1 for ; Mon, 01 Feb 2021 10:32:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=X1e7uq4kR7Qyf8vg6mQEwE7WTrkblxRLBormJ+wirLs=; b=C+4W+EV1opsXLhh2x0cuvBhCUOHqnGSj5+6rJa/B97H211efoahq0vQlM+jCDl3Y11 K/xnDxVOwdvdPMMtIhJl2y1H9K+Pz39rVMDLQKolNmGWRSrDK3aydtsvDvKnzpQGSGlc cJH5FXyeGzUJOWurqtWKI9wt13iOVpBgoYeuoKalIkMvCVjfRhn8iUmojlTBu46PM2Jg Azde8IEVIXhM6VChQ+l0bEdOCv+NIKRDoHIPvZ+2+SWEBn0cRXlHthRBW2XvJsGXuh17 2rkOKp2NqChqqT08u3yV8IEAUhmZtM+DYYILNZnshe3Vvk+lOb1iEpYZ2NH/W8NZ6Zgy CBMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=X1e7uq4kR7Qyf8vg6mQEwE7WTrkblxRLBormJ+wirLs=; b=jbfIHtFMOJuXxRA8qRlaa3miPGaDOydh/OsrSIYBRxr5c/sNY7ijmElbY2O6YjtV0u pMiMWOtXFlwHg5GxwS8H+SD5XtKu+9hbDnx/btXKk3G61c5BFqZOHpJcIEM/RF/PujMc +QuyRc26JSTcaNsoqpyaAqAT23U1VpD2MhC8fAN1lC+Y58RLD4ujGexWrwT0b1qV2ZSS 8i5h94NgcOqVaPjBsKuzmx+Vt7HfY3pjnObCBnt5s5NGNOVJsdUSCa5dXqDWIkZNvZ5F G4NU2QC/IjeXTpcX7M3sDJ/RnXbWr6l8AzPVIiPVeWP9o/bUuCMtSXFncfw8pYPPF9ua BS1g== X-Gm-Message-State: AOAM533PNYMj/VhKTCTHyrLPkqDJIOVTIcdmJtiqhoQXR7op+tX3/YH5 tFQlXwArlXg9IE8XqRhVbhJOPw== X-Google-Smtp-Source: ABdhPJxteAGEppN8MDkMgzCZyAxEHssuXAw6nVj17GUrFFkCiZmxU3XNsfUysd4wW5k56sT0G6SJHg== X-Received: by 2002:a1c:7fca:: with SMTP id a193mr155625wmd.189.1612204375560; Mon, 01 Feb 2021 10:32:55 -0800 (PST) Received: from google.com (230.69.233.35.bc.googleusercontent.com. [35.233.69.230]) by smtp.gmail.com with ESMTPSA id i15sm119475wmq.26.2021.02.01.10.32.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Feb 2021 10:32:54 -0800 (PST) Date: Mon, 1 Feb 2021 18:32:52 +0000 From: Quentin Perret To: Will Deacon Subject: Re: [RFC PATCH v2 06/26] KVM: arm64: Factor memory allocation out of pgtable.c Message-ID: References: <20210108121524.656872-1-qperret@google.com> <20210108121524.656872-7-qperret@google.com> <20210201181607.GD15632@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210201181607.GD15632@willie-the-truck> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210201_133257_336089_AF3C10FB X-CRM114-Status: GOOD ( 35.58 ) 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: Mark Rutland , devicetree@vger.kernel.org, kernel-team@android.com, Suzuki K Poulose , android-kvm@google.com, Catalin Marinas , Fuad Tabba , linux-kernel@vger.kernel.org, Rob Herring , James Morse , linux-arm-kernel@lists.infradead.org, Marc Zyngier , David Brazdil , Frank Rowand , kvmarm@lists.cs.columbia.edu, Julien Thierry 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 Monday 01 Feb 2021 at 18:16:08 (+0000), Will Deacon wrote: > On Fri, Jan 08, 2021 at 12:15:04PM +0000, Quentin Perret wrote: > > In preparation for enabling the creation of page-tables at EL2, factor > > all memory allocation out of the page-table code, hence making it > > re-usable with any compatible memory allocator. > > > > No functional changes intended. > > > > Signed-off-by: Quentin Perret > > --- > > arch/arm64/include/asm/kvm_pgtable.h | 32 +++++++++- > > arch/arm64/kvm/hyp/pgtable.c | 90 +++++++++++++++++----------- > > arch/arm64/kvm/mmu.c | 70 +++++++++++++++++++++- > > 3 files changed, 154 insertions(+), 38 deletions(-) > > > > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h > > index 52ab38db04c7..45acc9dc6c45 100644 > > --- a/arch/arm64/include/asm/kvm_pgtable.h > > +++ b/arch/arm64/include/asm/kvm_pgtable.h > > @@ -13,17 +13,41 @@ > > > > typedef u64 kvm_pte_t; > > > > +/** > > + * struct kvm_pgtable_mm_ops - Memory management callbacks. > > + * @zalloc_page: Allocate a zeroed memory page. > > Please describe the 'arg' parameter. > > > + * @zalloc_pages_exact: Allocate an exact number of zeroed memory pages. > > I think this comment coulld be expanded somewhat to make it clear that (a) > the 'size' parameter is in bytes rather than pages (b) the rounding > behaviour applied if 'size' is not page-aligned and (c) that the resulting > allocation is physically contiguous. > > > + * @free_pages_exact: Free an exact number of memory pages. > > + * @get_page: Increment the refcount on a page. > > + * @put_page: Decrement the refcount on a page. > > + * @page_count: Returns the refcount of a page. > > + * @phys_to_virt: Convert a physical address into a virtual address. > > + * @virt_to_phys: Convert a virtual address into a physical address. > > I think it would be good to be explicit about the nature of the virtual > address here. We've dealing with virtual addresses that are mapped in the > current context rather than e.g. guest virtual addresses. Ack to all the above. > > + */ > > +struct kvm_pgtable_mm_ops { > > + void* (*zalloc_page)(void *arg); > > + void* (*zalloc_pages_exact)(size_t size); > > + void (*free_pages_exact)(void *addr, size_t size); > > + void (*get_page)(void *addr); > > + void (*put_page)(void *addr); > > + int (*page_count)(void *addr); > > + void* (*phys_to_virt)(phys_addr_t phys); > > + phys_addr_t (*virt_to_phys)(void *addr); > > +}; > > [...] > > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > > index 1f41173e6149..278e163beda4 100644 > > --- a/arch/arm64/kvm/mmu.c > > +++ b/arch/arm64/kvm/mmu.c > > @@ -88,6 +88,48 @@ static bool kvm_is_device_pfn(unsigned long pfn) > > return !pfn_valid(pfn); > > } > > > > +static void *stage2_memcache_alloc_page(void *arg) > > +{ > > + struct kvm_mmu_memory_cache *mc = arg; > > + kvm_pte_t *ptep = NULL; > > + > > + /* Allocated with GFP_KERNEL_ACCOUNT, so no need to zero */ > > I couldn't spot where GFP_KERNEL_ACCOUNT implies __GFP_ZERO. I'm not suprised, it doesn't. Broken comment clearly, I'll fix with s/GFP_KERNEL_ACCOUNT/__GFP_ZERO > Please can you elaborate? > > > + if (mc && mc->nobjs) > > + ptep = mc->objects[--mc->nobjs]; > > + > > + return ptep; > > +} > > Why can't we use kvm_mmu_memory_cache_alloc() directly instead of opening up > the memory_cache? I think we can -- that function didn't exist when I first wrote this, but no good reason not to use it now. > > +static void *kvm_host_zalloc_pages_exact(size_t size) > > +{ > > + return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO); > > Hmm, so now we're passing __GFP_ZERO? ;) :-) > > +static void kvm_host_get_page(void *addr) > > +{ > > + get_page(virt_to_page(addr)); > > +} > > + > > +static void kvm_host_put_page(void *addr) > > +{ > > + put_page(virt_to_page(addr)); > > +} > > + > > +static int kvm_host_page_count(void *addr) > > +{ > > + return page_count(virt_to_page(addr)); > > +} > > + > > +static phys_addr_t kvm_host_pa(void *addr) > > +{ > > + return __pa(addr); > > +} > > + > > +static void *kvm_host_va(phys_addr_t phys) > > +{ > > + return __va(phys); > > +} > > + > > /* > > * Unmapping vs dcache management: > > * > > @@ -351,6 +393,17 @@ int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size, > > return 0; > > } > > > > +static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = { > > + .zalloc_page = stage2_memcache_alloc_page, > > + .zalloc_pages_exact = kvm_host_zalloc_pages_exact, > > + .free_pages_exact = free_pages_exact, > > + .get_page = kvm_host_get_page, > > + .put_page = kvm_host_put_page, > > + .page_count = kvm_host_page_count, > > + .phys_to_virt = kvm_host_va, > > + .virt_to_phys = kvm_host_pa, > > +}; > > Idle thought, but I wonder whether it would be better to have these > implementations as the default and make the mm_ops structure parameter > to kvm_pgtable_stage2_init() optional? I guess you don't gain an awful > lot though, so feel free to ignore me. No strong opinion really, but I suppose I could do something as simple as having static inline wrappers which provide kvm_s2_mm_ops to the pgtable API for me. I'll probably want to make sure these are not defined when compiling EL2 code, though, to avoid confusion. Or maybe you had something else in mind? Cheers, Quentin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel