From patchwork Tue Sep 26 18:19:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 13399516 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 58758E7E62B for ; Tue, 26 Sep 2023 18:20:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: References:Mime-Version:In-Reply-To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=L3305J+cZ+wGBTivc/stj/5Jbmg+iSekhtrpZ2Uj6Ig=; b=pcc8knIdNRENhZvEW1kMGNNKpC hXHNedu6VqtY5/tfrKerLxVP+QBMJwlhHMxHgWOwgzXtEHey0bjIzGdxCA5kqmheqQ25+oAXguY0l BJqOQGtNUl92b7sZBG19Nc6yF4R+acm4adR+eQUf3T7XUd2tSNFSBo4LZSPIe9H+e1trZZtwl4n0B p6IUphM+tCGaiD4YHMBGcGXvbGdU4PKhCzuBtUJG1xAgracFaqIqDZb8Z477zuMPUhVmEPG+PSAI0 DQ0xIgKXKIbykWEbA8L4mDOlMYSgxhmDbpUgtGmVi+2/y/mbDiFu9gvO+t2Sujtv1Hgj+I7NlMqjL JrOpiJAg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qlCfA-00GpiW-09; Tue, 26 Sep 2023 18:20:00 +0000 Received: from mail-yw1-x114a.google.com ([2607:f8b0:4864:20::114a]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qlCf0-00Gpfa-2C for linux-arm-kernel@lists.infradead.org; Tue, 26 Sep 2023 18:19:52 +0000 Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-59f67676065so108580537b3.0 for ; Tue, 26 Sep 2023 11:19:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695752388; x=1696357188; darn=lists.infradead.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=7evrq3PKBiHzaLA4DGci/aYqgw5Y4nsW4sL/8l2Nq7I=; b=T3DiBQv2ZnyIWcXSYFbLKMwJAJfi1OyDWNxRc3VG5a9SVWWCuQ5cCA+VCY6KDzRuhs RiwuWLbjhaG+Obdg9l3s1gGcAQjB3X3GiLGPkXVuubL7aRB7qMwrNA5mwoxxKFO4SmSE u+mlK7OC9Slfsj2UWLykql6W5UuX1KyHGi/cCEJ7fGr61p13pnb/6oumszBlcXHunNRk QCG+oAqrUxi/1BmFRiQNrRg8Fn3nRFMiPwh+aETiHVZn9wZTUQc3oUB5CiF/5eErMsjC K2S23AJiI08q9WAqyetFkraRHM9gT7qX5QUCDgQlSpLGV/3GrkS2pMcOSemucypEK1bd bqxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695752388; x=1696357188; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7evrq3PKBiHzaLA4DGci/aYqgw5Y4nsW4sL/8l2Nq7I=; b=KeaaULqcelDx0D+l9r4Cs6URnZiA/HVLQCrk7GAqXHp1wN4J9ddUct2Sp2i4xb1ECy j3sYYqu6L8Z7LK6JiR7xTUAbfxTHwrQts8XklyQk8zfpGYFKeGybRGgiksOg4qIcsImf FODif8fKiJUygq57qZcYqv1A3AYuovrD3/TGu/xXUnVnqzUz4lULcleNb0tuFjjurlAI rfhX5Y75HWlyGaURrQ6SyMiJZwl73e+qx6hBrZLYDg9884hlU+fznoMHRNaUZ5m7OJgz pSdIyA+d5SoGAR8uVVgPB9oiLGC/jSMIFFfxoB/lqIlFbR7rdih36/eLc58iRimtIjCe Uq6Q== X-Gm-Message-State: AOJu0YwJUcCsRyZ2asJVRhn9w3nYnxY6NuYsjtZ37Sj93PSGdDMqtkJN wREzwGAsCOvM+6UOpBAJDdphPBu/q+wL+sXi X-Google-Smtp-Source: AGHT+IFsBLgs3gQ7K5g/UspJwVgIViCv0ygjK5w+Pz4KI1o7o1An2/fTMUVh8EL5Mm2ZDlEZ0xrd5xxhWPj51vn2 X-Received: from vdonnefort.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:2eea]) (user=vdonnefort job=sendgmr) by 2002:a0d:ec10:0:b0:59b:e1db:562c with SMTP id q16-20020a0dec10000000b0059be1db562cmr140768ywn.5.1695752388237; Tue, 26 Sep 2023 11:19:48 -0700 (PDT) Date: Tue, 26 Sep 2023 19:19:32 +0100 In-Reply-To: <20230926181932.1650692-1-vdonnefort@google.com> Mime-Version: 1.0 References: <20230926181932.1650692-1-vdonnefort@google.com> X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Message-ID: <20230926181932.1650692-3-vdonnefort@google.com> Subject: [PATCH v1 2/2] KVM: arm64: Use folio for THP adjustment From: Vincent Donnefort To: maz@kernel.org, oliver.upton@linux.dev Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kernel-team@android.com, will@kernel.org, willy@infradead.org, Vincent Donnefort X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230926_111950_727533_77B3C74D X-CRM114-Status: GOOD ( 14.44 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Now transparent huge pages use folios, we can check efficiently if a page is mapped by a block by checking the folio size. This is saving a page table walk. It is safe to read the folio in this path. We've just increased its refcount (GUP from __gfn_to_pfn_memslot()). This will prevent attempts of splitting the huge page. Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index de5e5148ef5d..69fcbcc7aca5 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -791,51 +791,6 @@ int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size, return 0; } -static struct kvm_pgtable_mm_ops kvm_user_mm_ops = { - /* We shouldn't need any other callback to walk the PT */ - .phys_to_virt = kvm_host_va, -}; - -static int get_user_mapping_size(struct kvm *kvm, u64 addr) -{ - struct kvm_pgtable pgt = { - .pgd = (kvm_pteref_t)kvm->mm->pgd, - .ia_bits = vabits_actual, - .start_level = (KVM_PGTABLE_MAX_LEVELS - - CONFIG_PGTABLE_LEVELS), - .mm_ops = &kvm_user_mm_ops, - }; - unsigned long flags; - kvm_pte_t pte = 0; /* Keep GCC quiet... */ - u32 level = ~0; - int ret; - - /* - * Disable IRQs so that we hazard against a concurrent - * teardown of the userspace page tables (which relies on - * IPI-ing threads). - */ - local_irq_save(flags); - ret = kvm_pgtable_get_leaf(&pgt, addr, &pte, &level); - local_irq_restore(flags); - - if (ret) - return ret; - - /* - * Not seeing an error, but not updating level? Something went - * deeply wrong... - */ - if (WARN_ON(level >= KVM_PGTABLE_MAX_LEVELS)) - return -EFAULT; - - /* Oops, the userspace PTs are gone... Replay the fault */ - if (!kvm_pte_valid(pte)) - return -EAGAIN; - - return BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level)); -} - static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = { .zalloc_page = stage2_memcache_zalloc_page, .zalloc_pages_exact = kvm_s2_zalloc_pages_exact, @@ -1274,7 +1229,7 @@ static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot, * * Returns the size of the mapping. */ -static long +static unsigned long transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long hva, kvm_pfn_t *pfnp, phys_addr_t *ipap) @@ -1287,10 +1242,7 @@ transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot, * block map is contained within the memslot. */ if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) { - int sz = get_user_mapping_size(kvm, hva); - - if (sz < 0) - return sz; + size_t sz = folio_size(pfn_folio(pfn)); if (sz < PMD_SIZE) return PAGE_SIZE; @@ -1385,7 +1337,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, kvm_pfn_t pfn; bool logging_active = memslot_is_logging(memslot); unsigned long fault_level = kvm_vcpu_trap_get_fault_level(vcpu); - long vma_pagesize, fault_granule; + unsigned long vma_pagesize, fault_granule; enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; struct kvm_pgtable *pgt; @@ -1530,11 +1482,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, vma_pagesize = transparent_hugepage_adjust(kvm, memslot, hva, &pfn, &fault_ipa); - - if (vma_pagesize < 0) { - ret = vma_pagesize; - goto out_unlock; - } } if (fault_status != ESR_ELx_FSC_PERM && !device && kvm_has_mte(kvm)) {