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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 361C0C3DA64 for ; Thu, 1 Aug 2024 07:35:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ZXl0lmEbS1hXihbMlBatXbUIh4HdyFvgSMGYxQzLvM8=; b=K7xldvAbI3DmAhlFJTWfL+uAm8 czjGUBbpXqyHEfChZMEDJTEJVPG8ls9iBnfHjqR9mWgVPkj5hqtugxzpwLbIhvMrkF45ADcAlB3OH FzWNOnX232l4VlSRhqxLNMLIgMzVTk6h/mo/XS2iYYPMcWC+V39Y9ziBT/VLelfayE9R0jJ1oj78R oNQ3Q2HNT74hR+GYXY8XpiGK4p61cLmoRrbF5L3aWt+QybQcTThbLmBhYDBlF6/yblqZa4qMhT2mT J5hWEt87S/C8UOSVbb2dtrpbA6Tms233owvDtdSG7fiStJRY6fc2AB1cRPyZH5B81OZob661ou5/X ahX/W0lw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZQLR-00000004BlY-1EX7; Thu, 01 Aug 2024 07:35:29 +0000 Received: from sin.source.kernel.org ([145.40.73.55]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZQKx-00000004Bdh-3gKM; Thu, 01 Aug 2024 07:35:01 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id B8D90CE11E0; Thu, 1 Aug 2024 07:34:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C540CC4AF0A; Thu, 1 Aug 2024 07:34:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722497697; bh=4fAL4cODCnjl0NV8qGw/Qqudnit/5hoHCsZrciMhbUs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=hm6lqGrnGLdGUt29ZxrQ9cGwGC5e/My8adr9xG8pGwOWvxzaIy2wVVZecHcsaS7MD 2vhxDp5qw6P6jWSVDdYpSlndt26lYMY/9L3hrdQVP6XL1jiOwA3de3PchwMF07I1N4 2YEHskiwTzLI1+iwXeDgxTjbuc9HN0GjQyrYNiG+t6NhVrrxrlXYCf8VJMbSS/9yNs oHiP/3JEHHEyg0SbxiUkt+heXZ9wY3Uvo6jOHCc4TGv31tTJIER/7SKgCRJbrwGHtk ninurOs1MqcQM+fogPcJEhZWkju/RfarTKElxrf4Eq/YQ9RcoW3WZjBJcrAerVNRjv rukvhfzurLf/A== X-Mailer: emacs 31.0.50 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: Sean Christopherson , Paolo Bonzini , Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Sean Christopherson Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack , David Stevens Subject: Re: [PATCH v12 02/84] KVM: arm64: Disallow copying MTE to guest memory while KVM is dirty logging In-Reply-To: <20240726235234.228822-3-seanjc@google.com> References: <20240726235234.228822-1-seanjc@google.com> <20240726235234.228822-3-seanjc@google.com> Date: Thu, 01 Aug 2024 13:04:43 +0530 Message-ID: MIME-Version: 1.0 Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240801_003500_118881_9CA7D5F5 X-CRM114-Status: GOOD ( 15.98 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Sean Christopherson writes: > Disallow copying MTE tags to guest memory while KVM is dirty logging, as > writing guest memory without marking the gfn as dirty in the memslot could > result in userspace failing to migrate the updated page. Ideally (maybe?), > KVM would simply mark the gfn as dirty, but there is no vCPU to work with, > and presumably the only use case for copy MTE tags _to_ the guest is when > restoring state on the target. > > Fixes: f0376edb1ddc ("KVM: arm64: Add ioctl to fetch/store tags in a guest") > Signed-off-by: Sean Christopherson > --- > arch/arm64/kvm/guest.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c > index e1f0ff08836a..962f985977c2 100644 > --- a/arch/arm64/kvm/guest.c > +++ b/arch/arm64/kvm/guest.c > @@ -1045,6 +1045,11 @@ int kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm, > > mutex_lock(&kvm->slots_lock); > > + if (write && atomic_read(&kvm->nr_memslots_dirty_logging)) { > + ret = -EBUSY; > + goto out; > + } > + > is this equivalent to kvm_follow_pfn() with kfp->pin = 1 ? Should all those pin request fail if kvm->nr_memslots_dirty_logging != 0? > while (length > 0) { > kvm_pfn_t pfn = gfn_to_pfn_prot(kvm, gfn, write, NULL); > void *maddr; > -- > 2.46.0.rc1.232.g9752f9e123-goog