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 F2445C8300C for ; Fri, 9 Jun 2023 15:00:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241534AbjFIPAU (ORCPT ); Fri, 9 Jun 2023 11:00:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241594AbjFIO75 (ORCPT ); Fri, 9 Jun 2023 10:59:57 -0400 Received: from out-8.mta1.migadu.com (out-8.mta1.migadu.com [95.215.58.8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31009269A for ; Fri, 9 Jun 2023 07:59:56 -0700 (PDT) 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-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230608172112.GA1606@willie-the-truck> X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.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