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=-19.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 15FCFC433B4 for ; Thu, 6 May 2021 17:17:21 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 5F2B9610D2 for ; Thu, 6 May 2021 17:17:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F2B9610D2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id C7BB24B5C6; Thu, 6 May 2021 13:17:19 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id iK5XoPavTo5n; Thu, 6 May 2021 13:17:17 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E44DB4B562; Thu, 6 May 2021 13:17:17 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 27A254B562 for ; Thu, 6 May 2021 13:17:16 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IPhuyMnLpcZ0 for ; Thu, 6 May 2021 13:17:15 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id E3D654086C for ; Thu, 6 May 2021 13:17:14 -0400 (EDT) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D5C67610A7; Thu, 6 May 2021 17:17:13 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1lehcd-00BItA-H8; Thu, 06 May 2021 18:17:11 +0100 Date: Thu, 06 May 2021 18:17:10 +0100 Message-ID: <87lf8rrdd5.wl-maz@kernel.org> From: Marc Zyngier To: Zenghui Yu Subject: Re: [PATCH v2 03/11] KVM: arm64: Make kvm_skip_instr() and co private to HYP In-Reply-To: References: <20201102164045.264512-1-maz@kernel.org> <20201102164045.264512-4-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, kernel-team@android.com, will@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, ascull@google.com, mark.rutland@arm.com, qperret@google.com, dbrazdil@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: kvm@vger.kernel.org, kernel-team@android.com, Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Wed, 05 May 2021 15:23:02 +0100, Zenghui Yu wrote: > > Hi Marc, > > On 2020/11/3 0:40, Marc Zyngier wrote: > > In an effort to remove the vcpu PC manipulations from EL1 on nVHE > > systems, move kvm_skip_instr() to be HYP-specific. EL1's intent > > to increment PC post emulation is now signalled via a flag in the > > vcpu structure. > > > > Signed-off-by: Marc Zyngier > > [...] > > > @@ -133,6 +134,8 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) > > __load_guest_stage2(vcpu->arch.hw_mmu); > > __activate_traps(vcpu); > > + __adjust_pc(vcpu); > > If the INCREMENT_PC flag was set (e.g., for WFx emulation) while we're > handling PSCI CPU_ON call targetting this VCPU, the *target_pc* (aka > entry point address, normally provided by the primary VCPU) will be > unexpectedly incremented here. That's pretty bad, I think. > > This was noticed with a latest guest kernel, at least with commit > dccc9da22ded ("arm64: Improve parking of stopped CPUs"), which put the > stopped VCPUs in the WFx loop. The guest kernel shouted at me that > > "CPU: CPUs started in inconsistent modes" > > *after* rebooting. The problem is that the secondary entry point was > corrupted by KVM as explained above. All of the secondary processors > started from set_cpu_boot_mode_flag(), with w0=0. Oh well... FWIW, I've pushed out a test branch[1] with two patches that sit on top of Linus' current tree. I'll rebase and post it as soon as -rc1 appears, but I'd appreciate if you could have a look in the meantime. Thanks, M. [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pc-fixes -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm