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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 9960ACCD1BF for ; Fri, 24 Oct 2025 15:05:51 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4ctR6k1JQ5z3c55; Sat, 25 Oct 2025 02:05:50 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1761318350; cv=none; b=g5jvn/QMovEOJC48NDgjP0HWC2d6VPMKyc3l+rSeOReFOiFT5N6iw0Gtks/beZlqoHwvwJ3ebgipHWLi8lLebHKo6j8unEkdESD1VjS/5OZUQjWQciQm7mU2MVu/hOu8SMkulHNjuruT0ZMFcHgPRZLDCT30/wmb0em0DC7b0lWpeG8QhMdhb3DIGKAPXx4LTvJINAFTpKVyRLpZchTV8CoS5wN8kvdBshLs74x5Cr5AUIDaaBK7ClcUzNzPHFFuMjL2p55GhUoMdMxvwzdWo62V6zBXznENISja2rRsoABLvrX7WenR1lV33xXrwLZHlzmHNc0nB8WYfHlal0yK7A== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1761318350; c=relaxed/relaxed; bh=mFsntFKm3sLCSsUTazR6Zz09gRvrPjOBy+0/EZ6kZlE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TNyJxsHpppXFmnAStCHV2obzP8Ks1McYX8pPiXe+V2XzoWHpiWoZuO6IzG0sy+4yNLZ9qgCEIRF4EL4PhHmMqKsbfSys3V1DDKtuFyTjPU1Bu4YVwXugJ583PT3qObTY9GK8B/yjs/JeAvxN+S5UHR+McQugKoVMC/HnSwET9RpUc4VQy+8T3RlOuj7BJEp1DNL4qzVl3QkZOtS/mBq+s308amfbyQ2B2kAfbfhMBMuixZ6q/v3a3PfP+s9G3XHMnVBQOkVnz4KP57CBQ6pmk1g0qbPc/3oeZLNY+SbeMcQ/elMFIqEQ+35CjYdZIXGgXFjW+W3x/xBaFNL0XsNlTg== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=kevin.brodsky@arm.com; receiver=lists.ozlabs.org) smtp.mailfrom=arm.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=kevin.brodsky@arm.com; receiver=lists.ozlabs.org) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4ctR6j3jgTz3bs7 for ; Sat, 25 Oct 2025 02:05:49 +1100 (AEDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 29D6E14BF; Fri, 24 Oct 2025 08:05:10 -0700 (PDT) Received: from [10.57.67.38] (unknown [10.57.67.38]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 519063F63F; Fri, 24 Oct 2025 08:05:10 -0700 (PDT) Message-ID: <6ed9f404-9939-4e9f-b5aa-4253bef46df1@arm.com> Date: Fri, 24 Oct 2025 17:05:07 +0200 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 11/13] x86/xen: use lazy_mmu_state when context-switching To: David Woodhouse , David Hildenbrand , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , "David S. Miller" , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Ryan Roberts , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20251015082727.2395128-1-kevin.brodsky@arm.com> <20251015082727.2395128-12-kevin.brodsky@arm.com> <348e5f1c5a90e4ab0f14b4d997baf7169745bf04.camel@infradead.org> Content-Language: en-GB From: Kevin Brodsky In-Reply-To: <348e5f1c5a90e4ab0f14b4d997baf7169745bf04.camel@infradead.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 24/10/2025 16:47, David Woodhouse wrote: > On Thu, 2025-10-23 at 22:06 +0200, David Hildenbrand wrote: >> On 15.10.25 10:27, Kevin Brodsky wrote: >>> We currently set a TIF flag when scheduling out a task that is in >>> lazy MMU mode, in order to restore it when the task is scheduled >>> again. >>> >>> The generic lazy_mmu layer now tracks whether a task is in lazy MMU >>> mode in task_struct::lazy_mmu_state. We can therefore check that >>> state when switching to the new task, instead of using a separate >>> TIF flag. >>> >>> Signed-off-by: Kevin Brodsky >>> --- >> >> Looks ok to me, but I hope we get some confirmation from x86 / xen >> folks. > > I know tglx has shouted at me in the past for precisely this reminder, > but you know you can test Xen guests under QEMU/KVM now and don't need > to actually run Xen? Has this been boot tested? I considered boot-testing a Xen guest (considering the Xen-specific changes in this series), but having no idea how to go about it I quickly gave up... Happy to follow instructions :) - Kevin