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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECE93CDB47E for ; Wed, 18 Oct 2023 13:31:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344665AbjJRNbS (ORCPT ); Wed, 18 Oct 2023 09:31:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231660AbjJRNbQ (ORCPT ); Wed, 18 Oct 2023 09:31:16 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A015795 for ; Wed, 18 Oct 2023 06:31:14 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3894BC433C7; Wed, 18 Oct 2023 13:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697635874; bh=cBsM5tjvzRhJ+nQiO8bUjbNiG5H8jidCAiH3Q0Vh2Vk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=mXWj93n6k/vDi0Ro4euF5pI9zFRG02dtIUgz7DhE2Jo6w4KvKfy/ikbRkF1VZORvd t9FsDcNdNFs/hQjYDmtm/P+gSjOlL//8IHHTCdHdpidsh1z+PctlNeJTAn3QLpmivA hGUZp1c/8sy5a4/Ycktn2jFV5Yt7NGySv4uLiGDx4ZzX13vXofUPmuin3UQ+dc2UXQ +uOf4I4c7VOaLshgCm+B4YDaST/3dRwWUR76zLJ6yC/qzT7+zGLZzD59XkSACUfQdF SosHvrSYkaXRKdvtjZHxU/CNiJwDpvigwxUYBI84Ex5wHSiwVNWl+Tlqj7oHbaxjrO iVLxfIZ0vo9FA== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1qt6dj-005Mms-MX; Wed, 18 Oct 2023 14:31:11 +0100 Date: Wed, 18 Oct 2023 14:31:11 +0100 Message-ID: <86o7gwm50g.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org, James Morse , Suzuki K Poulose , Zenghui Yu Subject: Re: [PATCH v2 2/2] KVM: arm64: Virtualise PMEVTYPER_EL1.{NSU,NSK} In-Reply-To: <20231013052901.170138-3-oliver.upton@linux.dev> References: <20231013052901.170138-1-oliver.upton@linux.dev> <20231013052901.170138-3-oliver.upton@linux.dev> 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/29.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: oliver.upton@linux.dev, kvmarm@lists.linux.dev, kvm@vger.kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, 13 Oct 2023 06:29:01 +0100, Oliver Upton wrote: > > Suzuki noticed that KVM's PMU emulation is oblivious to the NSU and NSK > event filter bits. On systems that have EL3 these bits modify the > filter behavior in non-secure EL0 and EL1, respectively. Even though the > kernel doesn't use these bits, it is entirely possible some other guest > OS does. But what does it mean for KVM itself? We have no EL3 to speak of as far as a guest is concerned. And the moment we allow things like NSU/NSK to be set, why don't we allow M as well? Thanks, M. -- Without deviation from the norm, progress is not possible.