From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (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 2F0B11487F6 for ; Fri, 17 Oct 2025 01:46:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760665562; cv=none; b=Dc7UD9y5t9XMPZbxHqhedaQBkreVWKYiAB1MmBLfbLnh05/lg55I8KMHrSGvgW8Ev4xLW6N/rrwjUVCAYvnFKonBs0W5jahEoEIoMoFm2UP+10ms+gPXdnp3im6PovLgwT73D6Lib7ZL4CquVE9PKTw0dMmGGGMNvgrYKsJHwo8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760665562; c=relaxed/simple; bh=STs8Y+GLuT3+amxLmUST+PZ8gj8KTQE9Glui5npCtTo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lOqCS5Z8zxYhD0jp/Sn1ameQwYkhQbuacaxm2eNwKn4gPeGGMOH9/cLBstgJpt3Pj8I0BgllZ3Nq2bQAAJo+EDQal/PNcd0dfAJMUUYmAsL/0xVgjdT8sj0kX7iZhnAdki35l2KjlhMKUDimjmxNMAsKJaQJi7UD3b//U0TIS0M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=IR9yqRnz; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="IR9yqRnz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1760665561; x=1792201561; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=STs8Y+GLuT3+amxLmUST+PZ8gj8KTQE9Glui5npCtTo=; b=IR9yqRnz61Owh8NijBgxhAhWaP7x7jfOh2q6fgJoM+jOkPSxvdG9toV7 PbdulIOe68jRoJFkT0X/CK/8Ly/Kh5e9G3YJZFBuA6NupDPSa47/YHs+1 OLFuqjFrZuf5VnHZgwBsT66LaD67C4WjY7Gb1ZcIxp7ZQKtLspoWs0eih 8l/6h3QvZZL4H4xVJh37PceTOmVod8/rtC8XYwehZac6bx9CMkGJXXzst NEgFioymZiZsouTNd83HZgLcwUNaicDC4hxh1BEZdKxyN2XZ+AOJoTZBB l/fPVksuxSiB25OqNOA9WZPJtiJ9s8fT2kS7mqfdj/arxL0Xoe/VJcAi3 g==; X-CSE-ConnectionGUID: 39vhSPm4RH+RKf9FB3Us0g== X-CSE-MsgGUID: sDt6ihSkTSCXKolEd7s0zw== X-IronPort-AV: E=McAfee;i="6800,10657,11584"; a="62082049" X-IronPort-AV: E=Sophos;i="6.19,234,1754982000"; d="scan'208";a="62082049" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Oct 2025 18:46:00 -0700 X-CSE-ConnectionGUID: VLbXrEyqS+mO5QoMlH6F3Q== X-CSE-MsgGUID: YKaojFyXR1qwVxffdSsIwA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,234,1754982000"; d="scan'208";a="181744500" Received: from allen-sbox.sh.intel.com (HELO [10.239.159.30]) ([10.239.159.30]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Oct 2025 18:45:54 -0700 Message-ID: <11cad2be-9402-4d45-8d2b-c92d8962edfc@linux.intel.com> Date: Fri, 17 Oct 2025 09:42:10 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 0/7] Fix stale IOTLB entries for kernel address space To: Dave Hansen , Andrew Morton Cc: Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , Jason Gunthorpe , Jann Horn , Vasant Hegde , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Alistair Popple , Peter Zijlstra , Uladzislau Rezki , Jean-Philippe Brucker , Andy Lutomirski , Yi Lai , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Michal Hocko , Matthew Wilcox , iommu@lists.linux.dev, security@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20251014130437.1090448-1-baolu.lu@linux.intel.com> <20251014174339.c7b7d2cfb9f60d225e4fe5ec@linux-foundation.org> <6b187b20-6017-4f85-93ac-529d5df33aa2@linux.intel.com> Content-Language: en-US From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/15/25 23:55, Dave Hansen wrote: >>> Only [7/7] has acc:stable, even though that patch is not at all >>> backportable.  Please give some thought and suggestions regarding >>> whether you think we should backport this into earlier kernels. >> Yes. We should backport this series to stable kernels. >> >>> If "yes" then the size and scope of the series looks problematic.  Is >>> it possible to put together something simple and expedient just to plug >>> the hole in older kernels? >> Squashing some patches is one way. But would it be workable to backport >> this series manually? Say, could we send a pull request to the stable >> mailing list after this series has landed? > I honestly think we should just disable SVA in old kernels at compile > time, or at least default it to be disabled at runtime. That's the > simplest thing. > > The other alternative is to have arch_vmap_pmd_supported() return false > when SVA is active, or maybe when it's supported on the platform. > > Either of those are 10-ish lines of code and easy to backport. Hi iommu folks, any insights on this? Thanks, baolu