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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 279DDC31E40 for ; Tue, 6 Aug 2019 06:32:14 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EFE06206A2 for ; Tue, 6 Aug 2019 06:32:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="TdCsa0ID" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFE06206A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=rQBQH/8tNNlq67IY+pobenUltzzr8c96XTU31HuW59k=; b=TdCsa0IDCGFrA/mWJI1+bejFr SUngFXGmG+uGhltDsyarXqtOl/R++jwzr3drPuO/yNjmCyAY+3+48pa0N2rhib4Dvs5oojVAPj3hH 3zsp4z0Dxl3XE+5zgFxh6HDLtqW6z8WjzCwTJT4Fyq3KBQhWzxi/d+Q4LaNQ+zpB+bqMAtxVSJ/cm Xrhf0jniETDdyWh/CveaPUlo9V4XRfaAgJ/H2cIsNu85hvd5HwhrBtxF7Gy2do9y2jFuKFUmRNRqJ FybcnKPeakgfG83LdsbEdwUoS/4/Jk6w6LajbwA9qv7sgdnFMaiQmyJ9baNwf2MM66O+9W46XcsKO kJac4xqog==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hut13-0004c6-Ev; Tue, 06 Aug 2019 06:32:13 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hut0z-0004b7-5x for linux-arm-kernel@lists.infradead.org; Tue, 06 Aug 2019 06:32:11 +0000 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id E3131677EF7A9412FF53; Tue, 6 Aug 2019 14:31:56 +0800 (CST) Received: from [127.0.0.1] (10.184.12.158) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Tue, 6 Aug 2019 14:31:46 +0800 Subject: Re: [PATCH 1/2] KVM: arm64: Don't write junk to sysregs on reset To: Marc Zyngier , , , References: <20190805121555.130897-1-maz@kernel.org> <20190805121555.130897-2-maz@kernel.org> From: Zenghui Yu Message-ID: <01b74492-c59f-dfd9-e439-752e6b1c53dc@huawei.com> Date: Tue, 6 Aug 2019 14:29:20 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:64.0) Gecko/20100101 Thunderbird/64.0 MIME-Version: 1.0 In-Reply-To: <20190805121555.130897-2-maz@kernel.org> Content-Language: en-US X-Originating-IP: [10.184.12.158] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190805_233209_412797_541D40FE X-CRM114-Status: GOOD ( 12.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Jones , James Morse , Julien Thierry , Suzuki K Poulose Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Marc, On 2019/8/5 20:15, Marc Zyngier wrote: > At the moment, the way we reset system registers is mildly insane: > We write junk to them, call the reset functions, and then check that > we have something else in them. > > The "fun" thing is that this can happen while the guest is running > (PSCI, for example). If anything in KVM has to evaluate the state > of a system register while junk is in there, bad thing may happen. > > Let's stop doing that. Instead, we track that we have called a > reset function for that register, and assume that the reset > function has done something. This requires fixing a couple of > sysreg refinition in the trap table. > > In the end, the very need of this reset check is pretty dubious, > as it doesn't check everything (a lot of the sysregs leave outside of > the sys_regs[] array). It may well be axed in the near future. > > Signed-off-by: Marc Zyngier (Regardless of whether this check is needed or not,) I tested this patch with kvm-unit-tests: for i in {1..100}; do QEMU=/path/to/qemu-system-aarch64 accel=kvm arch=arm64 ./run_tests.sh; done And all the tests passed! Thanks, zenghui _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel