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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBD68C433EF for ; Mon, 18 Oct 2021 11:07:40 +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 A6A8160F11 for ; Mon, 18 Oct 2021 11:07:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A6A8160F11 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=rTnZM5SWtPZAol5kr+XezwCGbNukm/LHw06u1Cab8jc=; b=NTVGSc/1gN5Zu0 cDTVq6GMaZeRzVSir0CH4VdgLP+d9iy4xJdfh3MMtnKrug/6A52AuciP/DNx95byAwl0fSfR0KTgL x/eScXAC9hScOOYDnjTwuuim/ctKYVmGM+RrTW0ZUOmfEh4ozRCsfiJ1a6keO4mOutgsnetowU9r8 DNSWvHmgOVThKlIFfYapRArsbyJLJwYbb+UjZLGA36lOiscOnRscP9+lat7LpuXbvlTg+lT2zndmV 1PX4siXHdWkkecHs9rQIabM5DjNQGWYmrZyFYxNuA+XEFmM1MkAAkS4vtlS+VjxyEyjuLXG85hdvs O8XVWD83YAQwWFlDkoeA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mcQSz-00FFET-2P; Mon, 18 Oct 2021 11:06:06 +0000 Received: from mail-wr1-x42f.google.com ([2a00:1450:4864:20::42f]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mcQEl-00F8TK-AZ for linux-arm-kernel@lists.infradead.org; Mon, 18 Oct 2021 10:51:25 +0000 Received: by mail-wr1-x42f.google.com with SMTP id v17so40461655wrv.9 for ; Mon, 18 Oct 2021 03:51:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=EUaW7JwfSGO8IfMzxXtAbFj7chATqlw6VUjN7U2ryQM=; b=gsh2UkIAMsm5gYe5c49OiGWmzsspPVgjB2PAZkdcBDhHzqjXni96n8WS2mo1deqjcp EAWvXhBI3vbC6FovJLqT+tzcAWgqGm27iLzkbUAHDk51q01CC0bWX2vHMA22sXq8cNrV FYGbGg1+1E6kzv8/MgEDzSJxpJ+m0Lq1Rpz7qj/xrP5MJ8Y3b44gQ4tBk9n/TNizOR7x jwhOMhPLLLQhu+zdIKywI8J/ckZX+WWuMWn0FCdCRChKJwdSZ/ybmc0sP1AyY0y02Sst 8j2wT9/pm1hfRlBeHG1YiMYxoXjAKAINmnfHZ8VIOfHMxyWEItndpA0p9wAbQ99sH2QF tXpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=EUaW7JwfSGO8IfMzxXtAbFj7chATqlw6VUjN7U2ryQM=; b=bgMRdxw+2PRxe3SFoSJoVEjjvOmst61xj0jzZGfyI6L7J82U+fAwXck5jBjBp7eidV ZeuiQF+96hLTrqU04BiSHdW6DqIQt9FlTcwXQhkdcH3/PbrGU2WmYhgxmj7J6gemOfKi Zwm4MQTVESQehKqmu3W34ROgOWQ3840BRjC8w6Sfkc5t0nOPqH4SQh9R8vMrO5oy4FXf Gxj9lJ5sC+7ERV9Uuur0IxhErkXtSuvDEFj0hW21gOohNuknNXJ3DZyEcTHDk/CsXJ4+ uje4qxg7eabbdlHISpYTKMzESdiQ2/Ez0J+pIYZSDftzG8DFev2CfzUtqInFw2cUUUEH fiMg== X-Gm-Message-State: AOAM533uRc1xjG34NjNJDSpkquC627Ue/M6G7YLso93+uQhvY8omfgPk o3dmWrk7QxY1TNVGlVgkg6s94A== X-Google-Smtp-Source: ABdhPJwhtb3NOEzuy2ZFJYNVEotlalYXUtDQUgg53zsWLVY3XRXYV7dP0NvO8Pf6NgSALYKR0zEs3g== X-Received: by 2002:a5d:59a9:: with SMTP id p9mr35745131wrr.386.1634554281829; Mon, 18 Oct 2021 03:51:21 -0700 (PDT) Received: from google.com ([2a00:79e0:d:210:ba81:6f1b:ab2e:f120]) by smtp.gmail.com with ESMTPSA id h8sm13921425wrm.27.2021.10.18.03.51.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Oct 2021 03:51:21 -0700 (PDT) Date: Mon, 18 Oct 2021 11:51:18 +0100 From: Quentin Perret To: Marc Zyngier Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , Fuad Tabba , David Brazdil , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH 04/16] KVM: arm64: Introduce kvm_share_hyp() Message-ID: References: <20211013155831.943476-1-qperret@google.com> <20211013155831.943476-5-qperret@google.com> <875ytworvy.wl-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <875ytworvy.wl-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211018_035123_420948_2C6BD836 X-CRM114-Status: GOOD ( 21.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sunday 17 Oct 2021 at 11:41:21 (+0100), Marc Zyngier wrote: > Not directly related to this code, but it looks to me that > kvm_host_owns_hyp_mappings() really ought to check for > is_kernel_in_hyp_mode() on its own. VHE really deals with its own > mappings, and create_hyp_mappings() already has a check to do nothing > on VHE. Sure, I'll stick a patch at the beginning of the series. > > > + > > + return pkvm_share_hyp(kvm_kaddr_to_phys(from), kvm_kaddr_to_phys(to)); > > +} > > + > > /** > > * create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode > > * @from: The virtual kernel start address of the range > > @@ -316,12 +327,8 @@ int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot) > > if (is_kernel_in_hyp_mode()) > > return 0; > > > > - if (!kvm_host_owns_hyp_mappings()) { > > - if (WARN_ON(prot != PAGE_HYP)) > > - return -EPERM; > > - return pkvm_share_hyp(kvm_kaddr_to_phys(from), > > - kvm_kaddr_to_phys(to)); > > - } > > + if (WARN_ON(!kvm_host_owns_hyp_mappings())) > > + return -EPERM; > > Do we really need this? Can't we just verify that all the code paths > to create_hyp_mappings() check for kvm_host_owns_hyp_mappings()? > > At the very least, make this a VM_BUG_ON() so that this is limited to > debug. Yes, I'm quickly developing a WARN_ON()-phobia. Right, that _is_ purely debug. It's just that folks are used to being able to just call create_hyp_mappings() for anything, so I wanted to make sure we have an easy way to catch future changes that would unknowingly break pKVM, but no objection to make this VM_BUG_ON(). Cheers, Quentin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel