From patchwork Mon May 13 14:38:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Chartre X-Patchwork-Id: 10941137 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9B7C06C5 for ; Mon, 13 May 2019 14:42:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8D2B227861 for ; Mon, 13 May 2019 14:42:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 80BB22832D; Mon, 13 May 2019 14:42:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2E5F227861 for ; Mon, 13 May 2019 14:42:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730310AbfEMOjp (ORCPT ); Mon, 13 May 2019 10:39:45 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:59418 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730144AbfEMOjo (ORCPT ); Mon, 13 May 2019 10:39:44 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x4DEd2YY194903; Mon, 13 May 2019 14:39:05 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2018-07-02; bh=BckiUE2qwd6ce7s4e94ZCEH08ViWVb2Uhow4MmaOmmg=; b=MqxRlocDO4PBVSKI4njGqiBJNQ3Dwy7bXoxOg336yVqnxDPoOo4C8bDcoA+hRinUelY/ IfBGNpsi5hC0VByASVpiWMEgObQsMVJz2ebCqcSbAU7+bP+dXw4f4OP72FR/CyrWZMzm C5l9JlMKOqhD3L7yBz6qxyBISnDBFSOI418qbfcikgzUXjTPisA4nha1WqGfH00pB+fR MAPL3suB/BEgJ7y+NOdtYN4R08kIlmFj7UCcos/Hh23ufmYdF9aqYoILoddmclvElloo MtVyLdQhfuOp3oe6RJY+QcC2ZMynhm3bA4JOkdVlLXIFA7MOvRKhnhe+hFi0uBip4m9o lw== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2sdq1q7aum-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 May 2019 14:39:05 +0000 Received: from achartre-desktop.fr.oracle.com (dhcp-10-166-106-34.fr.oracle.com [10.166.106.34]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x4DEcZQB022780; Mon, 13 May 2019 14:39:02 GMT From: Alexandre Chartre To: pbonzini@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, kvm@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: konrad.wilk@oracle.com, jan.setjeeilers@oracle.com, liran.alon@oracle.com, jwadams@google.com, alexandre.chartre@oracle.com Subject: [RFC KVM 08/27] KVM: x86: Optimize branches which checks if address space isolation enabled Date: Mon, 13 May 2019 16:38:16 +0200 Message-Id: <1557758315-12667-9-git-send-email-alexandre.chartre@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1557758315-12667-1-git-send-email-alexandre.chartre@oracle.com> References: <1557758315-12667-1-git-send-email-alexandre.chartre@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9255 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905130103 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Liran Alon As every entry to guest checks if should switch from host_mm to kvm_mm, these branches is at very hot path. Optimize them by using static_branch. Signed-off-by: Liran Alon Signed-off-by: Alexandre Chartre --- arch/x86/kvm/isolation.c | 11 ++++++++--- arch/x86/kvm/isolation.h | 7 +++++++ 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/isolation.c b/arch/x86/kvm/isolation.c index eeb60c4..43fd924 100644 --- a/arch/x86/kvm/isolation.c +++ b/arch/x86/kvm/isolation.c @@ -23,6 +23,9 @@ struct mm_struct kvm_mm = { .mmlist = LIST_HEAD_INIT(kvm_mm.mmlist), }; +DEFINE_STATIC_KEY_FALSE(kvm_isolation_enabled); +EXPORT_SYMBOL(kvm_isolation_enabled); + /* * When set to true, KVM #VMExit handlers run in isolated address space * which maps only KVM required code and per-VM information instead of @@ -118,15 +121,17 @@ int kvm_isolation_init(void) kvm_isolation_set_handlers(); pr_info("KVM: x86: Running with isolated address space\n"); + static_branch_enable(&kvm_isolation_enabled); return 0; } void kvm_isolation_uninit(void) { - if (!address_space_isolation) + if (!kvm_isolation()) return; + static_branch_disable(&kvm_isolation_enabled); kvm_isolation_clear_handlers(); kvm_isolation_uninit_mm(); pr_info("KVM: x86: End of isolated address space\n"); @@ -140,7 +145,7 @@ void kvm_may_access_sensitive_data(struct kvm_vcpu *vcpu) void kvm_isolation_enter(void) { - if (address_space_isolation) { + if (kvm_isolation()) { /* * Switches to kvm_mm should happen from vCPU thread, * which should not be a kernel thread with no mm @@ -152,7 +157,7 @@ void kvm_isolation_enter(void) void kvm_isolation_exit(void) { - if (address_space_isolation) { + if (kvm_isolation()) { /* TODO: Kick sibling hyperthread before switch to host mm */ /* TODO: switch back to original mm */ } diff --git a/arch/x86/kvm/isolation.h b/arch/x86/kvm/isolation.h index 1290d32..aa5e979 100644 --- a/arch/x86/kvm/isolation.h +++ b/arch/x86/kvm/isolation.h @@ -4,6 +4,13 @@ #include +DECLARE_STATIC_KEY_FALSE(kvm_isolation_enabled); + +static inline bool kvm_isolation(void) +{ + return static_branch_likely(&kvm_isolation_enabled); +} + extern int kvm_isolation_init(void); extern void kvm_isolation_uninit(void); extern void kvm_isolation_enter(void);