From mboxrd@z Thu Jan 1 00:00:00 1970 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 6A069C19F2D for ; Tue, 9 Aug 2022 18:12:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343596AbiHISM0 (ORCPT ); Tue, 9 Aug 2022 14:12:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345444AbiHISLD (ORCPT ); Tue, 9 Aug 2022 14:11:03 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E4162A73D; Tue, 9 Aug 2022 11:04:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6AA9261052; Tue, 9 Aug 2022 18:04:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BDE9C43470; Tue, 9 Aug 2022 18:04:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660068263; bh=MWpWlqNZeOO/ShuZIfA1nr8DmytoetKzYgGqDWu40hw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=baWnn2G+pt9K8EB9IHdvDpRvWFKmohJOaouXjvt5ZPspyRSI33ZZ5v2Z4C1fg5zMr nhuUIqREotdp4E7THbPFrKLPYDu0KLuKLZTQnEKl46h1Do4fN5l7/+PTh221lXvAmh ogpEfRcDgxpnYlrWcJWjEWw5yz4ppGfwAz0JoJ+s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ricardo Koller , Reiji Watanabe , Raghavendra Rao Ananta , Andrew Jones , Paolo Bonzini , Sasha Levin Subject: [PATCH 5.10 12/23] selftests: KVM: Handle compiler optimizations in ucall Date: Tue, 9 Aug 2022 20:00:30 +0200 Message-Id: <20220809175513.304137593@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220809175512.853274191@linuxfoundation.org> References: <20220809175512.853274191@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Raghavendra Rao Ananta [ Upstream commit 9e2f6498efbbc880d7caa7935839e682b64fe5a6 ] The selftests, when built with newer versions of clang, is found to have over optimized guests' ucall() function, and eliminating the stores for uc.cmd (perhaps due to no immediate readers). This resulted in the userspace side always reading a value of '0', and causing multiple test failures. As a result, prevent the compiler from optimizing the stores in ucall() with WRITE_ONCE(). Suggested-by: Ricardo Koller Suggested-by: Reiji Watanabe Signed-off-by: Raghavendra Rao Ananta Message-Id: <20220615185706.1099208-1-rananta@google.com> Reviewed-by: Andrew Jones Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- tools/testing/selftests/kvm/lib/aarch64/ucall.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/kvm/lib/aarch64/ucall.c b/tools/testing/selftests/kvm/lib/aarch64/ucall.c index 2f37b90ee1a9..f600311fdc6a 100644 --- a/tools/testing/selftests/kvm/lib/aarch64/ucall.c +++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c @@ -73,20 +73,19 @@ void ucall_uninit(struct kvm_vm *vm) void ucall(uint64_t cmd, int nargs, ...) { - struct ucall uc = { - .cmd = cmd, - }; + struct ucall uc = {}; va_list va; int i; + WRITE_ONCE(uc.cmd, cmd); nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS; va_start(va, nargs); for (i = 0; i < nargs; ++i) - uc.args[i] = va_arg(va, uint64_t); + WRITE_ONCE(uc.args[i], va_arg(va, uint64_t)); va_end(va); - *ucall_exit_mmio_addr = (vm_vaddr_t)&uc; + WRITE_ONCE(*ucall_exit_mmio_addr, (vm_vaddr_t)&uc); } uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc) -- 2.35.1