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 B6061C00A8F for ; Tue, 24 Oct 2023 18:37:55 +0000 (UTC) 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=2hs4hhr+HIG/4sGTbRzuOUJ3S5GOflQgPmrEix6uu/I=; b=YxVQTqwqRZXn1c xSh9MprG2W3uv32560bdgyEOWDIJgAXKLr66iSgSI7Daav35dlJcpFWLjo4MU88EpIite8vKcA1Fb mu3THxaEU69rBLtEAQLhHGCOvXqFZ+nDOePgsD4gYcm0IYA1z7Omp4KY5f+JxXKtY6jq/ba4/gpPh lAb0cXggAQmUsafe6dljU/ZxgYlmnDJ9uoFHVt9va+DL508kQZN+jHqAGo/Sflu7nmz53LyffZvDN kAwEYDO2zlvdp8zQ18kRgLSXElGeKVhpoRXvydDCQCATDcIT54qgduApVbthaEqKvoUmPHli9PfqI v1bIH4VY5ALK73Ow3dww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qvMHP-00AgVg-0m; Tue, 24 Oct 2023 18:37:27 +0000 Received: from out-199.mta0.migadu.com ([91.218.175.199]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qvMHM-00AgVL-1e for linux-arm-kernel@lists.infradead.org; Tue, 24 Oct 2023 18:37:25 +0000 Date: Tue, 24 Oct 2023 18:37:17 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1698172642; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MhJ7hpYNLv+MdX49dQXGYnhsXLwtvTKjEUlM/EEP2AE=; b=HmTAi3vX6+c6qUUSeCE5bUS/PW6Yb7yhrXKc58eaEv/9GVTUSXOuF6uNnysiKo0GoNPB4+ wllIwNj9PbBKFHyTluy6Qg5zJaD4norqGkRmo9F0H9VtpK+aClTT4P2Q9V6v2Z+mlImQVr JneDsDassGEe43ScK3hMSWUrpVNfKZE= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Raghavendra Rao Ananta Cc: Marc Zyngier , Alexandru Elisei , James Morse , Suzuki K Poulose , Paolo Bonzini , Zenghui Yu , Shaoqin Huang , Jing Zhang , Reiji Watanabe , Colton Lewis , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v8 07/13] KVM: arm64: PMU: Allow userspace to limit PMCR_EL0.N for the guest Message-ID: References: <20231020214053.2144305-1-rananta@google.com> <20231020214053.2144305-8-rananta@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20231020214053.2144305-8-rananta@google.com> X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231024_113724_697117_531D6C45 X-CRM114-Status: GOOD ( 10.72 ) 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 Fri, Oct 20, 2023 at 09:40:47PM +0000, Raghavendra Rao Ananta wrote: [...] > + /* > + * Make PMCR immutable once the VM has started running, but > + * do not return an error to meet the existing expectations. > + */ > + if (kvm_vm_has_ran_once(vcpu->kvm)) { > + mutex_unlock(&kvm->arch.config_lock); > + return 0; > + } Marc pointed out offline that PMCR_EL0 needs to be mutable at runtime as well. I'll admit, the architecture isn't very helpful as it is both used for identification _and_ configuration. What I had in mind a few revisions ago when I gave the suggestion was to ignore writes to _just_ the PMCR_EL0.N field after the VM has started. -- Thanks, Oliver _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel