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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE887C77B7C for ; Fri, 26 May 2023 23:45:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243254AbjEZXpV (ORCPT ); Fri, 26 May 2023 19:45:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237862AbjEZXox (ORCPT ); Fri, 26 May 2023 19:44:53 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 600CEFB for ; Fri, 26 May 2023 16:44:50 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-babb53e6952so2824744276.0 for ; Fri, 26 May 2023 16:44:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1685144689; x=1687736689; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Bguo3hUZaLYxse9v+ik+MX3ufqUdHR10jXNpIhPD3cE=; b=Y62V38pt3Kf7P9M2YivEC5661SUHDQjGPJeLNpi65nB4y+p3TsqoRR0z/9AOIr1Kjf gl3yg0EBv9UJcyGGhkoV+eP5nxHHEckaVjNM+WV0ph8y6N8NKNrOoxejQzf6xVLF0GNF CMPzW7iyFKrk0I+YLOBH1dB2cwpR8z8XT9p+1tlyni+H85cDXJGB/ZGkaiDpbVC82/o/ GKwW1qcFloQI+vCY/C+X0I8xbKAWwMlWN0KpQsh6osmLARaX2g1tNlgMEbkEwKadQaPu 8s3poXNR7qoLyRgjp4108zRCziAP6oNak8GIUn6lV7gRCswVoQjlt0PKr+oTkaiyWyY0 Ciug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685144689; x=1687736689; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Bguo3hUZaLYxse9v+ik+MX3ufqUdHR10jXNpIhPD3cE=; b=O6Tq45B8/SUjJn/acDQPjN2mGXJOf45yFeGVb79BhHeB3Fb66frXH+fheo4fn/8D7S QD/aWmIPMuSBEPQ4L+9Yz+uceJyicG4kNnhxFyQWU310/qkj6bJqEQhAAPkwOka0oQa9 ZYHstEr7MUs/DXs2S66/g8Wa5zxn5OyL6OA6eWQbCH21JBhM/hqmk9ZCd6Al1Ja+0QM0 SAKKz7ZH2Z2lIeQEgP3kfjtHXsQtMUf9G4NbgqBykRVoYifzsZXHYUsotG++963X0kVX 7R7YzTZlvb7p2ZRHvCdup2Dup2O1U0jYD2uPF6ChJkVwPg6FS0jN8NSRr09TolQ5ZB0g IaIg== X-Gm-Message-State: AC+VfDztDg6i/UM1MD6LvNo6rtxIJd+CWmrbQQGPuWr8jveQ5QJiFB7X 3nQwLKhmfb9EuWCDhc/9sVaOyQAbKYo= X-Google-Smtp-Source: ACHHUZ72Yke0umLVJsAYBjLDCmB2C1ZbHNslgBIJrMfaEGzX80HaCkEwKhsoBR2khvT0ady9wDj4p4x/v3M= X-Received: from yuzhao.bld.corp.google.com ([2620:15c:183:200:910f:8a15:592b:2087]) (user=yuzhao job=sendgmr) by 2002:a25:3cb:0:b0:ba8:337a:d8a3 with SMTP id 194-20020a2503cb000000b00ba8337ad8a3mr1807757ybd.11.1685144689141; Fri, 26 May 2023 16:44:49 -0700 (PDT) Date: Fri, 26 May 2023 17:44:31 -0600 In-Reply-To: <20230526234435.662652-1-yuzhao@google.com> Message-Id: <20230526234435.662652-7-yuzhao@google.com> Mime-Version: 1.0 References: <20230526234435.662652-1-yuzhao@google.com> X-Mailer: git-send-email 2.41.0.rc0.172.g3f132b7071-goog Subject: [PATCH mm-unstable v2 06/10] kvm/powerpc: make radix page tables RCU safe From: Yu Zhao To: Andrew Morton , Paolo Bonzini Cc: Alistair Popple , Anup Patel , Ben Gardon , Borislav Petkov , Catalin Marinas , Chao Peng , Christophe Leroy , Dave Hansen , Fabiano Rosas , Gaosheng Cui , Gavin Shan , "H. Peter Anvin" , Ingo Molnar , James Morse , "Jason A. Donenfeld" , Jason Gunthorpe , Jonathan Corbet , Marc Zyngier , Masami Hiramatsu , Michael Ellerman , Michael Larabel , Mike Rapoport , Nicholas Piggin , Oliver Upton , Paul Mackerras , Peter Xu , Sean Christopherson , Steven Rostedt , Suzuki K Poulose , Thomas Gleixner , Thomas Huth , Will Deacon , Zenghui Yu , kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org, linux-mm@google.com, Yu Zhao Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org KVM page tables are currently not RCU safe against remapping, i.e., kvmppc_unmap_free_pmd_entry_table() et al. The previous mmu_notifier_ops members rely on kvm->mmu_lock to synchronize with that operation. However, the new mmu_notifier_ops member test_clear_young() provides a fast path that does not take kvm->mmu_lock. To implement kvm_arch_test_clear_young() for that path, orphan page tables need to be freed by RCU. Unmapping, specifically kvm_unmap_radix(), does not free page tables, hence not a concern. Signed-off-by: Yu Zhao --- arch/powerpc/kvm/book3s_64_mmu_radix.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c index 461307b89c3a..3b65b3b11041 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -1469,13 +1469,15 @@ int kvmppc_radix_init(void) { unsigned long size = sizeof(void *) << RADIX_PTE_INDEX_SIZE; - kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor); + kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, + SLAB_TYPESAFE_BY_RCU, pte_ctor); if (!kvm_pte_cache) return -ENOMEM; size = sizeof(void *) << RADIX_PMD_INDEX_SIZE; - kvm_pmd_cache = kmem_cache_create("kvm-pmd", size, size, 0, pmd_ctor); + kvm_pmd_cache = kmem_cache_create("kvm-pmd", size, size, + SLAB_TYPESAFE_BY_RCU, pmd_ctor); if (!kvm_pmd_cache) { kmem_cache_destroy(kvm_pte_cache); return -ENOMEM; -- 2.41.0.rc0.172.g3f132b7071-goog