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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 A4AEDC2BD10 for ; Wed, 14 Oct 2020 18:27:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DD792222A for ; Wed, 14 Oct 2020 18:27:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="s0GCOtZv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389350AbgJNS1u (ORCPT ); Wed, 14 Oct 2020 14:27:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389426AbgJNS1s (ORCPT ); Wed, 14 Oct 2020 14:27:48 -0400 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0AF76C0613D8 for ; Wed, 14 Oct 2020 11:27:34 -0700 (PDT) Received: by mail-qk1-x74a.google.com with SMTP id m126so349133qkd.13 for ; Wed, 14 Oct 2020 11:27:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=784t8a81EqGn9vK4Ge4RJ0ESjE9KKEOgOyqmynlKty8=; b=s0GCOtZv55Gjd1XHXBNohAfLhPXXnWUIpl5wRjQa0+qx7m9d24d8lNaf2d5GleFDYx FleZ1dK7ZTfsCYqTl3v8ni6T9+4V+z2sDpnoQRfG2nA/pIO4I4vguFIGpMIQZdbmggBo 87aIbQ3ugz5pmTHQDNkNwjji7NWAj9QFs4HvpHNHsVtEzowDK/n+MXtcofriSQVxpBCz AOF1ImkpJ3oHPXTl5IyeBlaNcRU0Mph+k+mCNJtE1a7dwdvyHgrYkHPvK3lkbAxzgd70 xLH0KM8bpSCr+0Q9RXVm88RwpmUaA48qFNld6VHL5c2f2OSaDu506sYRjPsZkCnaJrA+ Oy6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=784t8a81EqGn9vK4Ge4RJ0ESjE9KKEOgOyqmynlKty8=; b=rCNLJHN846NF76YBcpJ9GF55JiT2pez1ygzVkv3HYFhXoE5AROdIaNojxP8LUjnmEJ sG/AfkmPpR8wRQdWkETgMRj0ohkte3qvTtw6u9jdPjLS+2mM7bD64B7ZTxWhx2yCJ3fv tT2IUuQpo3kpk85LTu1aq3kQUZ1sLtDKfsYHdF9uC/6d34xLIS0sld440u+UZG4Iwr5w PlWZKG/h7ohsLtjinDL2sjA6k8Mk5zFNARgB31AL1O6JQljUzrTieBJc8xDcxmLwGysd hGq10FMBo0lNXPno4uqS/mJMohAIUeibdWwbKls8/j8ntxPjOA5ho5uLl3243+KOwOzW 6u3g== X-Gm-Message-State: AOAM5331noqxDJ5WiYLIfeL2QG/B2Yi6ACLG5R5oPwUyU1BLI3gogRlW qndAkGv3eb2lN62A/eMUliYATSiA1oAG X-Google-Smtp-Source: ABdhPJz0zfyLeokjzsNy8itq7rVjzagA+2DwEboiDW0FQFTIsV+gGl/ieGnSnFL25RShz2/4Btae//px32HM Sender: "bgardon via sendgmr" X-Received: from bgardon.sea.corp.google.com ([2620:15c:100:202:f693:9fff:fef4:a293]) (user=bgardon job=sendgmr) by 2002:a0c:9e0e:: with SMTP id p14mr547966qve.25.1602700053163; Wed, 14 Oct 2020 11:27:33 -0700 (PDT) Date: Wed, 14 Oct 2020 11:26:56 -0700 In-Reply-To: <20201014182700.2888246-1-bgardon@google.com> Message-Id: <20201014182700.2888246-17-bgardon@google.com> Mime-Version: 1.0 References: <20201014182700.2888246-1-bgardon@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v2 16/20] kvm: x86/mmu: Support disabling dirty logging for the tdp MMU From: Ben Gardon To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Cannon Matthews , Paolo Bonzini , Peter Xu , Sean Christopherson , Peter Shier , Peter Feiner , Junaid Shahid , Jim Mattson , Yulei Zhang , Wanpeng Li , Vitaly Kuznetsov , Xiao Guangrong , Ben Gardon Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Dirty logging ultimately breaks down MMU mappings to 4k granularity. When dirty logging is no longer needed, these granaular mappings represent a useless performance penalty. When dirty logging is disabled, search the paging structure for mappings that could be re-constituted into a large page mapping. Zap those mappings so that they can be faulted in again at a higher mapping level. Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell machine. This series introduced no new failures. This series can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 Signed-off-by: Ben Gardon --- arch/x86/kvm/mmu/mmu.c | 3 ++ arch/x86/kvm/mmu/tdp_mmu.c | 59 ++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/mmu/tdp_mmu.h | 2 ++ 3 files changed, 64 insertions(+) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index b2ce57761d2f1..8fcf5e955c475 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5918,6 +5918,9 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm, spin_lock(&kvm->mmu_lock); slot_handle_leaf(kvm, (struct kvm_memory_slot *)memslot, kvm_mmu_zap_collapsible_spte, true); + + if (kvm->arch.tdp_mmu_enabled) + kvm_tdp_mmu_zap_collapsible_sptes(kvm, memslot); spin_unlock(&kvm->mmu_lock); } diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 099c7d68aeb1d..94624cc1df84c 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1019,3 +1019,62 @@ bool kvm_tdp_mmu_slot_set_dirty(struct kvm *kvm, struct kvm_memory_slot *slot) return spte_set; } +/* + * Clear non-leaf entries (and free associated page tables) which could + * be replaced by large mappings, for GFNs within the slot. + */ +static void zap_collapsible_spte_range(struct kvm *kvm, + struct kvm_mmu_page *root, + gfn_t start, gfn_t end) +{ + struct tdp_iter iter; + kvm_pfn_t pfn; + bool spte_set = false; + + tdp_root_for_each_pte(iter, root, start, end) { + if (!is_shadow_present_pte(iter.old_spte) || + is_last_spte(iter.old_spte, iter.level)) + continue; + + pfn = spte_to_pfn(iter.old_spte); + if (kvm_is_reserved_pfn(pfn) || + !PageTransCompoundMap(pfn_to_page(pfn))) + continue; + + tdp_mmu_set_spte(kvm, &iter, 0); + spte_set = true; + + spte_set = !tdp_mmu_iter_cond_resched(kvm, &iter); + } + + if (spte_set) + kvm_flush_remote_tlbs(kvm); +} + +/* + * Clear non-leaf entries (and free associated page tables) which could + * be replaced by large mappings, for GFNs within the slot. + */ +void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm, + const struct kvm_memory_slot *slot) +{ + struct kvm_mmu_page *root; + int root_as_id; + + for_each_tdp_mmu_root(kvm, root) { + root_as_id = kvm_mmu_page_as_id(root); + if (root_as_id != slot->as_id) + continue; + + /* + * Take a reference on the root so that it cannot be freed if + * this thread releases the MMU lock and yields in this loop. + */ + get_tdp_mmu_root(kvm, root); + + zap_collapsible_spte_range(kvm, root, slot->base_gfn, + slot->base_gfn + slot->npages); + + put_tdp_mmu_root(kvm, root); + } +} diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h index add8bb97c56dd..dc4cdc5cc29f5 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.h +++ b/arch/x86/kvm/mmu/tdp_mmu.h @@ -38,4 +38,6 @@ void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm, gfn_t gfn, unsigned long mask, bool wrprot); bool kvm_tdp_mmu_slot_set_dirty(struct kvm *kvm, struct kvm_memory_slot *slot); +void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm, + const struct kvm_memory_slot *slot); #endif /* __KVM_X86_MMU_TDP_MMU_H */ -- 2.28.0.1011.ga647a8990f-goog