From patchwork Mon Oct 2 09:57:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 147280 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:2a8e:b0:403:3b70:6f57 with SMTP id in14csp1404982vqb; Mon, 2 Oct 2023 05:57:20 -0700 (PDT) X-Google-Smtp-Source: AGHT+IExvJCnU8ZzJQ8yBPHieJ4QFgjjQo9BlJ39lN1zqTV5VQ2Z7peeAzRb6UDcJvQuQhw5uRv2 X-Received: by 2002:a17:90a:bb96:b0:26d:54de:b0d6 with SMTP id v22-20020a17090abb9600b0026d54deb0d6mr8672520pjr.20.1696251440587; Mon, 02 Oct 2023 05:57:20 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1696251440; cv=none; d=google.com; s=arc-20160816; b=TU3koJUA74k4OygAvXetr/3YtNHCG3UeZNHXstwL5tXdztWrQjBFfc5rb+iiOd5dYE 1/HlzQDeq9QtksGzmq5iRhDxhIXoD+uTa4AHHMubiXYYLQRwcgJ5j1qopuS69DMGu4kL 3ZqlicjWFmlDV8HG2U2tu3UzX7g5wlz+9KY5tJT2o2AIZVqXLvHj0n/J9o1umM+uXXCp 20bQORQbV+WtbZqiO6ZeO05fUjpCSWO9mXwq5GetfcBAIwAd0pFCWs9zZaF9f2ZVKBL6 fyL788QPlwm8nDAP+IL1m3U2zS/8B2BFxArJXTeVicbqJS6xxLylR19fQSCRZa6MW440 IxsQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=oaLU75npsvq/54a8Sa025V+4+WzNDRn33upnn1s6+Ig=; fh=8AvbwpPKF0Qe5WwS5eyABOVDUChKGxIrkPaOnjrOqKo=; b=Cj+LEZqi8zDQcyh0z2XZeSvGbwLq39+YyLZJfZ94L8yxjhHNSlBASPjJtBM5XwXu5j eB6wwsNkmzT1BT36SBMMF8dg0O3XlqwUcywVgZXiY0unmrmFYkYqvT+eYPJ6N5KCenne J1qEy9uQPc6u/CJ8iRJye62aYPl7IRmr7hRxEwgAsQzUJJ7DwR/MmF/LRoIp09pPRdQb ZT4thegC3GnSZnznQBQY1SNqMUkaY7LBYX06WRUbC+lug1ZidlDwiAmM4WyceyOw7yG4 QfedCU7OSrplm8Bs/2DAVUqnsNDfuBC9vRo2DDNG+Ag7y1ra7Fz77fcsmeldhS6GvRE5 EiNA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@xen.org header.s=20200302mail header.b="q/ykCRK8"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from howler.vger.email (howler.vger.email. [23.128.96.34]) by mx.google.com with ESMTPS id gx15-20020a17090b124f00b00277374d74afsi7256226pjb.12.2023.10.02.05.57.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Oct 2023 05:57:20 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) client-ip=23.128.96.34; Authentication-Results: mx.google.com; dkim=pass header.i=@xen.org header.s=20200302mail header.b="q/ykCRK8"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by howler.vger.email (Postfix) with ESMTP id 8A03180756FD; Mon, 2 Oct 2023 03:00:52 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at howler.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236317AbjJBKAc (ORCPT + 16 others); Mon, 2 Oct 2023 06:00:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236241AbjJBKAV (ORCPT ); Mon, 2 Oct 2023 06:00:21 -0400 Received: from mail.xenproject.org (mail.xenproject.org [104.130.215.37]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 513B0CC6; Mon, 2 Oct 2023 03:00:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=oaLU75npsvq/54a8Sa025V+4+WzNDRn33upnn1s6+Ig=; b=q/ykCRK8JD/cssMkft43adWnmO dgFcx/5EExveHYpHaN2qOKKGko25vBzWjhhf5/NVwSP5/M/WTCNqBb4ip0t0km23eeoB95Lt1bDXf JOulZfz2FlZxo7iEZB51Q0Ks17fLm6Vha27xljU5mmelsOkNb5XOTZS8jn+Mukq7VcrM=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnFiq-000178-IA; Mon, 02 Oct 2023 10:00:16 +0000 Received: from ec2-63-33-11-17.eu-west-1.compute.amazonaws.com ([63.33.11.17] helo=REM-PW02S00X.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qnFgh-0000Ft-TV; Mon, 02 Oct 2023 09:58:04 +0000 From: Paul Durrant To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Paul Durrant , David Woodhouse , David Woodhouse , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , x86@kernel.org Subject: [PATCH v7 11/11] KVM: xen: allow vcpu_info content to be 'safely' copied Date: Mon, 2 Oct 2023 09:57:40 +0000 Message-Id: <20231002095740.1472907-12-paul@xen.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231002095740.1472907-1-paul@xen.org> References: <20231002095740.1472907-1-paul@xen.org> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Mon, 02 Oct 2023 03:00:52 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778648550583994324 X-GMAIL-MSGID: 1778648550583994324 From: Paul Durrant If the guest sets an explicit vcpu_info GPA then, for any of the first 32 vCPUs, the content of the default vcpu_info in the shared_info page must be copied into the new location. Because this copy may race with event delivery (which updates the 'evtchn_pending_sel' field in vcpu_info) we need a way to defer that until the copy is complete. Happily there is already a shadow of 'evtchn_pending_sel' in kvm_vcpu_xen that is used in atomic context if the vcpu_info PFN cache has been invalidated so that the update of vcpu_info can be deferred until the cache can be refreshed (on vCPU thread's the way back into guest context). So let's also use this shadow if the vcpu_info cache has been *deactivated*, so that the VMM can safely copy the vcpu_info content and then re-activate the cache with the new GPA. To do this, all we need to do is stop considering an inactive vcpu_info cache as a hard error in kvm_xen_set_evtchn_fast(). Signed-off-by: Paul Durrant Reviewed-by: David Woodhouse --- Cc: David Woodhouse Cc: Sean Christopherson Cc: Paolo Bonzini Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: x86@kernel.org v6: - New in this version. --- arch/x86/kvm/xen.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index aafc794940e4..e645066217bb 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -1606,9 +1606,6 @@ int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm) WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx); } - if (!vcpu->arch.xen.vcpu_info_cache.active) - return -EINVAL; - if (xe->port >= max_evtchn_port(kvm)) return -EINVAL;