From patchwork Fri Apr 5 11:58:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 13618952 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A1DA816C6A6 for ; Fri, 5 Apr 2024 11:58:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712318310; cv=none; b=exPUfEQDjBliQTp2tpqMRG3B2Rtiwgxw8QGE9H7NVy+ezqvGgXWC7uHvD/CSoyMuxif8ks7vhU29RwlEoyVc5FHSTaGjajGMGC9VF+6dFy4z2NJ0NM04KUdAuMLNVzROnkuo2ZEQgTUzI3uZC6LLFs1LQm0ZyyuOII6MA9wQzGw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712318310; c=relaxed/simple; bh=hH3qcfIlDFNFXcnOAXz5nQZISUR02/h+wK8MXGjdmhw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=qyp7/R6Uzz9nqHFgOMSGOcgUee+TyMx1a0liy9xF97t+qcuuL1DUhAJEcJJ1uVjN0W5/z8pJ+BlYtNIag/RWrB2txnQuNwaLT7/c/1tmvbCtjggV7Zv8a9p4FjgzC3Kl1w+/cGOBDgBuwhZCbqQCtVeySIP5va4cLtWiKUk2A9o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=RkQ+DeVS; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RkQ+DeVS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1712318307; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=54r2v6x4hCqSU9lpxJJX8F9xMdFOFqhWRrFs4bS58g8=; b=RkQ+DeVSLrpPt3jkvi8svCJgl1Zq954AHMnkHcy4BP/6ZDU8JF+RbP1cJStFfAbJWRc9qS Q6CS+2JUEFHY/cQnkk70XW3WZKwLNLaaxT95EaqSsSi1sk48vhDoJgbFnlXY3t+8Wwz/Y8 jlL9agajAP9MGlJZUYrPLHJEvWQFbJE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-653-1T7hKq5gPw2fRM982K2a_w-1; Fri, 05 Apr 2024 07:58:22 -0400 X-MC-Unique: 1T7hKq5gPw2fRM982K2a_w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C4A2888D0C8; Fri, 5 Apr 2024 11:58:20 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 13F6640C6CB3; Fri, 5 Apr 2024 11:58:20 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Thomas Bogendoerfer , Nicholas Piggin , Anup Patel , Atish Patra , Sean Christopherson , Andrew Morton , David Hildenbrand , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH 3/4] mmu_notifier: remove the .change_pte() callback Date: Fri, 5 Apr 2024 07:58:14 -0400 Message-ID: <20240405115815.3226315-4-pbonzini@redhat.com> In-Reply-To: <20240405115815.3226315-1-pbonzini@redhat.com> References: <20240405115815.3226315-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 The scope of set_pte_at_notify() has reduced more and more through the years. Initially, it was meant for when the change to the PTE was not bracketed by mmu_notifier_invalidate_range_{start,end}(). However, that has not been so for over ten years. During all this period the only implementation of .change_pte() was KVM and it had no actual functionality, because it was called after mmu_notifier_invalidate_range_start() zapped the secondary PTE. Now that this (nonfunctional) user of the .change_pte() callback is gone, the whole callback can be removed. For now, leave in place set_pte_at_notify() even though it is just a synonym for set_pte_at(). Signed-off-by: Paolo Bonzini Reviewed-by: David Hildenbrand --- include/linux/mmu_notifier.h | 46 ++---------------------------------- mm/mmu_notifier.c | 17 ------------- 2 files changed, 2 insertions(+), 61 deletions(-) diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index f349e08a9dfe..8c72bf651606 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -122,15 +122,6 @@ struct mmu_notifier_ops { struct mm_struct *mm, unsigned long address); - /* - * change_pte is called in cases that pte mapping to page is changed: - * for example, when ksm remaps pte to point to a new shared page. - */ - void (*change_pte)(struct mmu_notifier *subscription, - struct mm_struct *mm, - unsigned long address, - pte_t pte); - /* * invalidate_range_start() and invalidate_range_end() must be * paired and are called only when the mmap_lock and/or the @@ -392,8 +383,6 @@ extern int __mmu_notifier_clear_young(struct mm_struct *mm, unsigned long end); extern int __mmu_notifier_test_young(struct mm_struct *mm, unsigned long address); -extern void __mmu_notifier_change_pte(struct mm_struct *mm, - unsigned long address, pte_t pte); extern int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *r); extern void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *r); extern void __mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm, @@ -439,13 +428,6 @@ static inline int mmu_notifier_test_young(struct mm_struct *mm, return 0; } -static inline void mmu_notifier_change_pte(struct mm_struct *mm, - unsigned long address, pte_t pte) -{ - if (mm_has_notifiers(mm)) - __mmu_notifier_change_pte(mm, address, pte); -} - static inline void mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range) { @@ -581,26 +563,6 @@ static inline void mmu_notifier_range_init_owner( __young; \ }) -/* - * set_pte_at_notify() sets the pte _after_ running the notifier. - * This is safe to start by updating the secondary MMUs, because the primary MMU - * pte invalidate must have already happened with a ptep_clear_flush() before - * set_pte_at_notify() has been invoked. Updating the secondary MMUs first is - * required when we change both the protection of the mapping from read-only to - * read-write and the pfn (like during copy on write page faults). Otherwise the - * old page would remain mapped readonly in the secondary MMUs after the new - * page is already writable by some CPU through the primary MMU. - */ -#define set_pte_at_notify(__mm, __address, __ptep, __pte) \ -({ \ - struct mm_struct *___mm = __mm; \ - unsigned long ___address = __address; \ - pte_t ___pte = __pte; \ - \ - mmu_notifier_change_pte(___mm, ___address, ___pte); \ - set_pte_at(___mm, ___address, __ptep, ___pte); \ -}) - #else /* CONFIG_MMU_NOTIFIER */ struct mmu_notifier_range { @@ -650,11 +612,6 @@ static inline int mmu_notifier_test_young(struct mm_struct *mm, return 0; } -static inline void mmu_notifier_change_pte(struct mm_struct *mm, - unsigned long address, pte_t pte) -{ -} - static inline void mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range) { @@ -693,7 +650,6 @@ static inline void mmu_notifier_subscriptions_destroy(struct mm_struct *mm) #define ptep_clear_flush_notify ptep_clear_flush #define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush #define pudp_huge_clear_flush_notify pudp_huge_clear_flush -#define set_pte_at_notify set_pte_at static inline void mmu_notifier_synchronize(void) { @@ -701,4 +657,6 @@ static inline void mmu_notifier_synchronize(void) #endif /* CONFIG_MMU_NOTIFIER */ +#define set_pte_at_notify set_pte_at + #endif /* _LINUX_MMU_NOTIFIER_H */ diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index ec3b068cbbe6..8982e6139d07 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -424,23 +424,6 @@ int __mmu_notifier_test_young(struct mm_struct *mm, return young; } -void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address, - pte_t pte) -{ - struct mmu_notifier *subscription; - int id; - - id = srcu_read_lock(&srcu); - hlist_for_each_entry_rcu(subscription, - &mm->notifier_subscriptions->list, hlist, - srcu_read_lock_held(&srcu)) { - if (subscription->ops->change_pte) - subscription->ops->change_pte(subscription, mm, address, - pte); - } - srcu_read_unlock(&srcu, id); -} - static int mn_itree_invalidate(struct mmu_notifier_subscriptions *subscriptions, const struct mmu_notifier_range *range) {