From nobody Thu May 7 19:29:25 2026 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 4BD1BC433EF for ; Fri, 20 May 2022 06:25:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345811AbiETGZd (ORCPT ); Fri, 20 May 2022 02:25:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232003AbiETGZ1 (ORCPT ); Fri, 20 May 2022 02:25:27 -0400 X-Greylist: delayed 907 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 19 May 2022 23:25:25 PDT Received: from mail-m973.mail.163.com (mail-m973.mail.163.com [123.126.97.3]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 04ABA14C765; Thu, 19 May 2022 23:25:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=EDLaB jALBZshwxMN5oSHQMdP+5yMRSPM50LnskauBiI=; b=ZLThMmtfDaLxrmpAqjeXi QH3+pNFbEKqCDU4f3pgmMJeYX5ijiaoqUaYPpxQ/dFMltEmFc6XgtnJZ2Q821gWS ZHiFdmA6OSJpOmEgkvq/s4PxFrwxj+yFLqY11xzzxeKj0gsuoTOrygVLVPsgSglq 8evm833vcpAuKq2UhL5Ggs= Received: from localhost.localdomain (unknown [116.128.244.169]) by smtp3 (Coremail) with SMTP id G9xpCgA3TJyqMIdizyGuDg--.28397S2; Fri, 20 May 2022 14:09:47 +0800 (CST) From: Yun Lu To: pbonzini@redhat.com Cc: seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] KVM: x86/mmu: optimizing the code in mmu_try_to_unsync_pages Date: Fri, 20 May 2022 14:09:07 +0800 Message-Id: <20220520060907.863136-1-luyun_611@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: G9xpCgA3TJyqMIdizyGuDg--.28397S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Aw1DXFWxAF18trWfKr43GFg_yoW8GrW7pr ZrGrsIyr45GrsIq3s7Cw4kC347uws7KF48GryUWas8Zwn7K3s3ta4rKw4ftrs3XrWrGr1a va1ruF43WF18Jw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UJ8nrUUUUU= X-Originating-IP: [116.128.244.169] X-CM-SenderInfo: pox130jbwriqqrwthudrp/1tbiMgwHzlWBzeFtBQAAsn Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" There is no need to check can_unsync and prefetch in the loop every time, just move this check before the loop. Signed-off-by: Yun Lu --- arch/x86/kvm/mmu/mmu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 311e4e1d7870..e51e7735adca 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2534,6 +2534,12 @@ int mmu_try_to_unsync_pages(struct kvm *kvm, const s= truct kvm_memory_slot *slot, if (kvm_slot_page_track_is_active(kvm, slot, gfn, KVM_PAGE_TRACK_WRITE)) return -EPERM; =20 + if (!can_unsync) + return -EPERM; + + if (prefetch) + return -EEXIST; + /* * The page is not write-tracked, mark existing shadow pages unsync * unless KVM is synchronizing an unsync SP (can_unsync =3D false). In @@ -2541,15 +2547,9 @@ int mmu_try_to_unsync_pages(struct kvm *kvm, const s= truct kvm_memory_slot *slot, * allowing shadow pages to become unsync (writable by the guest). */ for_each_gfn_indirect_valid_sp(kvm, sp, gfn) { - if (!can_unsync) - return -EPERM; - if (sp->unsync) continue; =20 - if (prefetch) - return -EEXIST; - /* * TDP MMU page faults require an additional spinlock as they * run with mmu_lock held for read, not write, and the unsync --=20 2.25.1 No virus found Checked by Hillstone Network AntiVirus