From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-40.mta1.migadu.com (out-40.mta1.migadu.com [95.215.58.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8CD92171A3 for ; Fri, 9 Jun 2023 14:59:56 +0000 (UTC) Date: Fri, 9 Jun 2023 14:59:50 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1686322794; 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=tjX8DzT+VkdDDHfdUii6WZAg+8YtJ/Le8qPqCL2aFIg=; b=W1j3MzafFpna6foeRceMZoNVh+mGTUjdhwuAw8nMLJT3L1F1f2IJN6Mf9KJOvSOuRuiO6Q 1jLF5iAJd183k0VguYGNXFIS9TJy6XND+BMHrqBRkf04HI+VKUCz6lKW9nd+kjPKJMf2f1 PgNbT9fvR4pH0UChxo/8rFuqqN6KiH4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Will Deacon Cc: Marc Zyngier , Colton Lewis , kvm@vger.kernel.org, Catalin Marinas , James Morse , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev Subject: Re: [PATCH 3/3] KVM: arm64: Skip break phase when we have FEAT_BBM level 2 Message-ID: References: <20230602170147.1541355-1-coltonlewis@google.com> <20230602170147.1541355-4-coltonlewis@google.com> <87sfb7octw.wl-maz@kernel.org> <20230608172112.GA1606@willie-the-truck> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230608172112.GA1606@willie-the-truck> X-Migadu-Flow: FLOW_OUT Hey Will, On Thu, Jun 08, 2023 at 06:21:13PM +0100, Will Deacon wrote: > > IIRC, Colton was testing largely with permission relaxation, and had > > forward progress issues b.c. the stale TLB entry was never invalidated > > in response to a permission fault. > > Would the series at: > > https://lore.kernel.org/r/5d8e1f752051173d2d1b5c3e14b54eb3506ed3ef.1684892404.git-series.apopple@nvidia.com > > help with that? Heh, that's a rather interesting patch :) I don't think it is directly related to the problem Colton encounters, though the symptoms are similar. This crops up when KVM uses a stricter permission set than the primary MMU, like lazy X for deferred I$ maintenance and write-protection for dirty logging. KVM policy led to the stale TLB entry, so KVM is the one that needs to initiate the invalidation. -- Thanks, Oliver 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 9EE25C7EE2E for ; Fri, 9 Jun 2023 15:00:31 +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=kRmi7v5OUmsc/saDVlNA2e3RijdhrEF+PyNTWhyi/48=; b=wS6xL6SCgEPb6x xPeJNr+y8/0TPM0h8ia1nYHeLEpVqA5orbhS7Sn1v7yCq7RP/jhifQstCJpZnX7GhiR6C/s+B2R/X dKeh44sI/Jxvnhv8LiY9DCY1VZAgvxZWpnwYIuQN4WPzEcsWvcndefmaJ5br3hTfLIE8GRT8jEP/I uQ59a7vPHJfuvVhyCj5B45bEuyJl/3T/bO/7QKm99I622AwwItMhR3H2ZtTeobtu39D2elyzsMFtQ TGG4As1TZhbie9QdwsuV4F1LTOY3fgxcK8ozYtUbkVjhYPeHyf2a00t7gzvnKy6+1jDCH3p3UqNIx lsKIVpoDg9IlSpvESNtA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q7dar-00DMST-2c; Fri, 09 Jun 2023 15:00:01 +0000 Received: from out-44.mta1.migadu.com ([95.215.58.44]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q7dao-00DMRs-1h for linux-arm-kernel@lists.infradead.org; Fri, 09 Jun 2023 15:00:00 +0000 Date: Fri, 9 Jun 2023 14:59:50 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1686322794; 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=tjX8DzT+VkdDDHfdUii6WZAg+8YtJ/Le8qPqCL2aFIg=; b=W1j3MzafFpna6foeRceMZoNVh+mGTUjdhwuAw8nMLJT3L1F1f2IJN6Mf9KJOvSOuRuiO6Q 1jLF5iAJd183k0VguYGNXFIS9TJy6XND+BMHrqBRkf04HI+VKUCz6lKW9nd+kjPKJMf2f1 PgNbT9fvR4pH0UChxo/8rFuqqN6KiH4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Will Deacon Cc: Marc Zyngier , Colton Lewis , kvm@vger.kernel.org, Catalin Marinas , James Morse , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev Subject: Re: [PATCH 3/3] KVM: arm64: Skip break phase when we have FEAT_BBM level 2 Message-ID: References: <20230602170147.1541355-1-coltonlewis@google.com> <20230602170147.1541355-4-coltonlewis@google.com> <87sfb7octw.wl-maz@kernel.org> <20230608172112.GA1606@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230608172112.GA1606@willie-the-truck> X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230609_075958_729855_839F2968 X-CRM114-Status: GOOD ( 11.85 ) 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 Hey Will, On Thu, Jun 08, 2023 at 06:21:13PM +0100, Will Deacon wrote: > > IIRC, Colton was testing largely with permission relaxation, and had > > forward progress issues b.c. the stale TLB entry was never invalidated > > in response to a permission fault. > > Would the series at: > > https://lore.kernel.org/r/5d8e1f752051173d2d1b5c3e14b54eb3506ed3ef.1684892404.git-series.apopple@nvidia.com > > help with that? Heh, that's a rather interesting patch :) I don't think it is directly related to the problem Colton encounters, though the symptoms are similar. This crops up when KVM uses a stricter permission set than the primary MMU, like lazy X for deferred I$ maintenance and write-protection for dirty logging. KVM policy led to the stale TLB entry, so KVM is the one that needs to initiate the invalidation. -- Thanks, Oliver _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel