From patchwork Sat Feb 11 01:46:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vipin Sharma X-Patchwork-Id: 13136695 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 0EC32C05027 for ; Sat, 11 Feb 2023 01:46:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230016AbjBKBqv (ORCPT ); Fri, 10 Feb 2023 20:46:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229977AbjBKBql (ORCPT ); Fri, 10 Feb 2023 20:46:41 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF84B84B91 for ; Fri, 10 Feb 2023 17:46:39 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id s4-20020a056a00194400b0058d9b9fecb6so3436637pfk.1 for ; Fri, 10 Feb 2023 17:46:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=+gGMkWLRs9fWzgoKMZp1xjTHNEtbWSt2tA+J164dR+I=; b=n4w2JvSZxbvAx7VDuTa8a6gnidk7+fM4SN3MoyITzRdo8Zusatugfb0N1mp7zDdAtm nkhT4ceurl+KSeBYu9KzUTa8oFiachS16q0TOsJhkSXmoY5VcCxLGE77JXnMLtd4AlJm nYaND+RHtk6DaGb8UbXmjF67jjmu7+tbRomwRl8q4whlT68/prZH4lf6oAKIuMqg3Oog 7jRUqsAdomH6eGOi5pQpQdIXfWvKdc17woQPwGK56J49NXm1kQFEkeER/UbFB7IRBE4E ds6/M+/hv1rxXm244otjozs+JI1/o3dSAAc9NOQzc/cN4c27HBZFHrDd9YmeV9F+D+Ts TwYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=+gGMkWLRs9fWzgoKMZp1xjTHNEtbWSt2tA+J164dR+I=; b=Fo2dcUIIxBt2y6eqt4uW3vkVXd9oMfCbiH1kfFf8DKMFKyGrgzctRu5wTEZRY5r2Hn xz821AqPLImV4BHQ/d4V8TWMrcR+GcEKvd51AlxA8BCADAoZhRAeU/PYcVOwKo/gcUJN OpMM+9EKqwMuy4Z8B/dgd+JU5ivrW+6hE8LeWjErIXrKcwzyXhIeJsDFp9V2d8tFsJbm ZriSMHkjtHiR5aKWxRGpo0Xhvn0X6kQ10f5Y970NZPtEjuH5MjEOsLBLVBl6qZBxdVEY HfVeS9a6ErRBFlTakWH13CQsyVHwTysQEUknYmwwRhIuB5Zm+TptldCqToDFjHxqHsh0 Z+yg== X-Gm-Message-State: AO0yUKX2oOJkHhe3b4yD59heEjjvID2RXKn5t2U8Pxu06CGngJJqYGW2 VIirNQvFNxMJ7nfYp/4VrmZgc4/MyDnN X-Google-Smtp-Source: AK7set8K9Pxm27vSO52D5ATEFyE/B/V3FGyDTFtREQw5bTFuoc9urcOJfrVPxABPSX++bn6TZOR+0gt2vq91 X-Received: from vipin.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:479f]) (user=vipinsh job=sendgmr) by 2002:a17:902:e84f:b0:189:6df9:4f85 with SMTP id t15-20020a170902e84f00b001896df94f85mr4137680plg.27.1676079999320; Fri, 10 Feb 2023 17:46:39 -0800 (PST) Date: Fri, 10 Feb 2023 17:46:23 -0800 In-Reply-To: <20230211014626.3659152-1-vipinsh@google.com> Mime-Version: 1.0 References: <20230211014626.3659152-1-vipinsh@google.com> X-Mailer: git-send-email 2.39.1.581.gbfd45094c4-goog Message-ID: <20230211014626.3659152-5-vipinsh@google.com> Subject: [Patch v3 4/7] KVM: x86/mmu: Optimize SPTE change for aging gfn range From: Vipin Sharma To: seanjc@google.com, pbonzini@redhat.com, bgardon@google.com, dmatlack@google.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Vipin Sharma Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org No need to check all of the conditions in __handle_changed_spte(). Aging a gfn range implies resetting access bit or marking spte for access tracking. Use atomic operation to only reset those bits. This avoids checking many conditions in __handle_changed_spte() API. Also, clean up code by removing dead code and API parameters. Signed-off-by: Vipin Sharma Reviewed-by: David Matlack --- arch/x86/kvm/mmu/tdp_mmu.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index c895560244de..5d6e77554797 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -758,13 +758,6 @@ static inline void tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, _tdp_mmu_set_spte(kvm, iter, new_spte, true); } -static inline void tdp_mmu_set_spte_no_acc_track(struct kvm *kvm, - struct tdp_iter *iter, - u64 new_spte) -{ - _tdp_mmu_set_spte(kvm, iter, new_spte, false); -} - #define tdp_root_for_each_pte(_iter, _root, _start, _end) \ for_each_tdp_pte(_iter, _root, _start, _end) @@ -1251,32 +1244,41 @@ static __always_inline bool kvm_tdp_mmu_handle_gfn(struct kvm *kvm, /* * Mark the SPTEs range of GFNs [start, end) unaccessed and return non-zero * if any of the GFNs in the range have been accessed. + * + * No need to mark corresponding PFN as accessed as this call is coming from + * the clear_young() or clear_flush_young() notifier, which uses the return + * value to determine if the page has been accessed. */ static bool age_gfn_range(struct kvm *kvm, struct tdp_iter *iter, struct kvm_gfn_range *range) { - u64 new_spte = 0; + u64 new_spte; /* If we have a non-accessed entry we don't need to change the pte. */ if (!is_accessed_spte(iter->old_spte)) return false; - new_spte = iter->old_spte; - - if (spte_ad_enabled(new_spte)) { - new_spte &= ~shadow_accessed_mask; + if (spte_ad_enabled(iter->old_spte)) { + iter->old_spte = tdp_mmu_clear_spte_bits(iter->sptep, + iter->old_spte, + shadow_accessed_mask, + iter->level); + new_spte = iter->old_spte & ~shadow_accessed_mask; } else { + new_spte = mark_spte_for_access_track(iter->old_spte); + iter->old_spte = kvm_tdp_mmu_write_spte(iter->sptep, + iter->old_spte, new_spte, + iter->level); /* * Capture the dirty status of the page, so that it doesn't get * lost when the SPTE is marked for access tracking. */ - if (is_writable_pte(new_spte)) - kvm_set_pfn_dirty(spte_to_pfn(new_spte)); - - new_spte = mark_spte_for_access_track(new_spte); + if (is_writable_pte(iter->old_spte)) + kvm_set_pfn_dirty(spte_to_pfn(iter->old_spte)); } - tdp_mmu_set_spte_no_acc_track(kvm, iter, new_spte); + trace_kvm_tdp_mmu_spte_changed(iter->as_id, iter->gfn, iter->level, + iter->old_spte, new_spte); return true; }