From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (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 5643C3F4DD6; Wed, 20 May 2026 18:18:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301108; cv=none; b=ajLAlKlRaCigy29rcWxr44XDMAfoz8qDyRWNROOOJzMFHY8cGGhqcbed+n1EzqVilohl6Vo0MpnB8+m1G+ZzMB+miMPMHU3D4vlH5kWkWEKxL41O8z1AWmvg1kYmU4ASqkUR2Ru899+QyfVqlDI6aDKbrQMuYZPx+JcatSPUAB8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301108; c=relaxed/simple; bh=gy/m35HK5R8C7OR4BcbU0s0pFCv8bAQqfqz4IIZi8A4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=epChi5Vwx/dmTTFCSE9w2yKCOlhTmXwTawhyAO7wcqClTs6FkDkPZDYyTivTcbomnwZjnIFKl0hcjpE1QP5siLd5pTqcgQGzvcsmqf5a/Ov9DLCNB+9j8Oqun15BWfLJbD2STc0VfrXpgJaWIjNMfspy5T2VRvuk4qwWKon/Rys= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=fWZwpr+W; arc=none smtp.client-ip=192.198.163.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="fWZwpr+W" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1779301108; x=1810837108; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=gy/m35HK5R8C7OR4BcbU0s0pFCv8bAQqfqz4IIZi8A4=; b=fWZwpr+WYVpKyfVbbGLP3Xqxusvs+b/NELp+fuh+10gakAtsT9ou4jBS IP+NKD4uxc41K1mK3lKd+vaGIQl13JEVcBlfDdLDDaZ8Qgpf1dvujXPIi gp5zBuUolB5O3bPjOwxhNfGiIRVLNsc9TrwIXpVSoK+n9wmzjmUWYq1xW TEIJOB90pbrnen/+xumWETLI3ixh16zJwVLlktHK1MDcH4hZ1dzgqTV8n ITkHHrLAwoICl4Ydc2w7T1yWC8UYp+TZC1sauS3cxaGFZcPCmVlsAJBY2 0bckshNSDJzRmGsjBuzHXQSsh1c8Tn/MJNO05N7IC/ZILQAqJsbWnQboO g==; X-CSE-ConnectionGUID: hXlSkvIPS+22BVXTZt6j6Q== X-CSE-MsgGUID: CqT2MmhtThah17Mot/3tIQ== X-IronPort-AV: E=McAfee;i="6800,10657,11792"; a="79236318" X-IronPort-AV: E=Sophos;i="6.23,244,1770624000"; d="scan'208";a="79236318" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2026 11:18:27 -0700 X-CSE-ConnectionGUID: Y+HAddT+Qp6qQu2M+r0nww== X-CSE-MsgGUID: Noowu3A7QjeMsoprFlNSXA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,244,1770624000"; d="scan'208";a="235850596" Received: from bradocaj-mobl.ger.corp.intel.com (HELO [10.125.109.205]) ([10.125.109.205]) by fmviesa006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2026 11:18:25 -0700 Message-ID: <144e80e3-1813-4c77-8c43-1f350f74230c@intel.com> Date: Wed, 20 May 2026 11:18:23 -0700 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] tools/testing/cxl: Align mock CFMWS to PMD_SIZE for ARM64 64K pages To: Richard Cheng , dave@stgolabs.net Cc: jonathan.cameron@huawei.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, fabio.m.de.francesco@linux.intel.com, ming.li@zohomail.com, linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, newtonl@nvidia.com, kristinc@nvidia.com, kaihengf@nvidia.com, kobak@nvidia.com References: <20260519233523.5991-1-icheng@nvidia.com> Content-Language: en-US From: Dave Jiang In-Reply-To: <20260519233523.5991-1-icheng@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/19/26 4:35 PM, Richard Cheng wrote: > cxl_test allocate synthetic CFMWS HPA windows out of a gen_pool and asks > the allocator for SZ_256M alignment. It has been sufficient on x86 with > 4k pages, arm64 with 4k pages since their PMD_SIZE are 2MB. > > But for 64k-page arm64 kernel with CONFIG_ARM64_64K_PAGES=y and > CONFIG_PGTABLE_LEVELS=3 , the PMD_SIZE is 512 MB, which is much larger > than the alignment cxl_test guarantees. That results in every CXL region > carved from that window inherits a mis-aligned start. > > The DAX driver's cxl_dax_region_probe() then calls "alloc_dax_region() > and the probe fails with -ENOMEM, with error message > > """ > cxl_dax_region dax_region1: probe with driver cxl_dax_region failed > with error -12 > """ > > It was hit while bringing up cxl_test on an ARM64 server with > ARM64_64K_PAGES config. > > Raise the alignment passed to "alloc"mock_res()" to the larger of > SZ_256M and PMD_SIZE so that the mock CFMWS window is always at least as > well-aligned as "alloc_dax_region()" require. https://sashiko.dev/#/patchset/20260519233523.5991-1-icheng%40nvidia.com Do you need to adjust length as well as alloc_dax_region() also checks length alignment? DJ > > Signed-off-by: Richard Cheng > Acked-by: Kai-Heng Feng > --- > tools/testing/cxl/test/cxl.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c > index 418669927fb0..b40e4bbcc958 100644 > --- a/tools/testing/cxl/test/cxl.c > +++ b/tools/testing/cxl/test/cxl.c > @@ -497,7 +497,8 @@ static int populate_cedt(void) > struct acpi_cedt_cfmws *window = mock_cfmws[i]; > > cfmws_elc_update(window, i); > - res = alloc_mock_res(window->window_size, SZ_256M); > + res = alloc_mock_res(window->window_size, > + max_t(int, SZ_256M, PMD_SIZE)); > if (!res) > return -ENOMEM; > window->base_hpa = res->range.start;