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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b4-20020a170903228400b0016bea2a8b16si1000424plh.364.2022.10.13.14.19.12; Thu, 13 Oct 2022 14:19:35 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=RGZk+Vdb; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230216AbiJMVP0 (ORCPT + 99 others); Thu, 13 Oct 2022 17:15:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230199AbiJMVOq (ORCPT ); Thu, 13 Oct 2022 17:14:46 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C782319375D for ; Thu, 13 Oct 2022 14:13:51 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id s13-20020a170902ea0d00b00183243c7a0fso1995857plg.3 for ; Thu, 13 Oct 2022 14:13:51 -0700 (PDT) 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:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=Ayk7WF1bhRdGwOMvSXaXxnD19B/O1/9Is88g4dKNZ4g=; b=RGZk+Vdb53lCuSorY1wAskL95mWskPoDQmOT0OPifoQMxC88+I+sUOzBcNwM2ES118 iW/lEHriL4Qg+SyNCkAnOE/F6nkNbWpyMPrn2QueInKh5I9bN/usi/JiSlITCWwhzV2w F6RhstB4XKOktzSjRK6gkJVtWkzoAHgddgAk7BJQH6HKFMpgykXSfdeLSPliTOAoC2SU OhvYMmXuZ77gQ7BXD0oc1vhaLxjItBGg0M0MZ4A4tbio5n4WSVH2CZsZU9ZjKFIddh25 2ojCOWdDUXvoEAgrXLJgd97RPQuSVYegtFiK5TFLdLpOqU8FtEIs1sigEXVw1rFG6IsE rsOQ== 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:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Ayk7WF1bhRdGwOMvSXaXxnD19B/O1/9Is88g4dKNZ4g=; b=DQeOMV/x+/1sxfGBqTBksX0FOfJpwcAeZ5wnw4bxqgmXnIS0lOMl/mSSJW0VIeiuTk t+7IDgbmSNhiPmBosQhv7MrpDDKnL8SJQyaVANF9YskdR/M2OSnS5M+JgH5bmJosncO+ xbkC7C10/ZNwT1MNRsoiHcaKlrarOvOhF/VLRP26lMnvvk+JL2My0ZnZnD8vH4kH50HU 2JTMqz2/A1WsoeggLtlhyc8W89Ky2GYIp4fSRmbCqEK0BHid+u2+CgVAxbgiuse2bgDF 7YSEAEAQOCpRZ5DMiNfgsNWwc9hVUhhrTiTSB7f6EYgWbunYy8KLMes3Yxm/Rraw82IS iZUQ== X-Gm-Message-State: ACrzQf1ax95849LkogvHlbE3+6xtKE0HqNrsfroZKDJ9oQH5cU6LN7Gf 1Nax5lO4ztmaXsdeOh9ss0Qv1sjby0s= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:aa7:9614:0:b0:562:b07b:ad62 with SMTP id q20-20020aa79614000000b00562b07bad62mr1641934pfg.79.1665695586079; Thu, 13 Oct 2022 14:13:06 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 13 Oct 2022 21:12:34 +0000 In-Reply-To: <20221013211234.1318131-1-seanjc@google.com> Mime-Version: 1.0 References: <20221013211234.1318131-1-seanjc@google.com> X-Mailer: git-send-email 2.38.0.413.g74048e4d9e-goog Message-ID: <20221013211234.1318131-17-seanjc@google.com> Subject: [PATCH v2 16/16] KVM: selftests: Mark "guest_saw_irq" as volatile in xen_shinfo_test From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Luczaj , David Woodhouse X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1746608823207741235?= X-GMAIL-MSGID: =?utf-8?q?1746608823207741235?= Tag "guest_saw_irq" as "volatile" to ensure that the compiler will never optimize away lookups. Relying on the compiler thinking that the flag is global and thus might change also works, but it's subtle, less robust, and looks like a bug at first glance, e.g. risks being "fixed" and breaking the test. Make the flag "static" as well since convincing the compiler it's global is no longer necessary. Alternatively, the flag could be accessed with {READ,WRITE}_ONCE(), but literally every access would need the wrappers, and eking out performance isn't exactly top priority for selftests. Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c b/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c index caa3f5ab9e10..2a5727188c8d 100644 --- a/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c +++ b/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c @@ -132,7 +132,7 @@ struct { struct kvm_irq_routing_entry entries[2]; } irq_routes; -bool guest_saw_irq; +static volatile bool guest_saw_irq; static void evtchn_handler(struct ex_regs *regs) {