From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 3ED941A255C; Tue, 15 Apr 2025 13:50:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744725023; cv=none; b=FwydAXypUaDsB9DlcCjtdjkrW+/Dx1ARH/a0H8LskNDMlogwHRqida8mUkRo5uV6SafGVbbQCs44Cs7dkQ17j8iifkQxCxOy5dwg+hITOADFcRqz6Uce1ollaLkoQlOPVTA9iAVBU//75sAKJ/MIc7p+b0s1ShXZaBMdbxgvscA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744725023; c=relaxed/simple; bh=52XFDEoVjctQ9OWQ9lFkBSvA/2Yp7/fB0SfA2WLVPfA=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=JHFyE/3ngvxjO2spieJob0p6M7+lZHKBwNdZ3jPT4CQgrbW9EhwzIJwZGPHUHSrCADDAZTVQa0NrkB41f9PjdwbZ7AfVCNt7qgi+cqxkWSvcx5wI0huFpTXvwUUFVlds01o5iLx8L3s06H9eE7mUBNVFOw5HKXB91WljAbMgAjM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4ZcQRM0YmWz67Ct8; Tue, 15 Apr 2025 21:46:07 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id 8DD17140144; Tue, 15 Apr 2025 21:50:18 +0800 (CST) Received: from localhost (10.203.177.66) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Tue, 15 Apr 2025 15:50:17 +0200 Date: Tue, 15 Apr 2025 14:50:16 +0100 From: Jonathan Cameron To: CC: , , , , , , , , , Alejandro Lucero Subject: Re: [PATCH v13 11/22] cxl: define a driver interface for HPA free space enumeration Message-ID: <20250415145016.00003725@huawei.com> In-Reply-To: <20250414151336.3852990-12-alejandro.lucero-palau@amd.com> References: <20250414151336.3852990-1-alejandro.lucero-palau@amd.com> <20250414151336.3852990-12-alejandro.lucero-palau@amd.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml100002.china.huawei.com (7.191.160.241) To frapeml500008.china.huawei.com (7.182.85.71) On Mon, 14 Apr 2025 16:13:25 +0100 alejandro.lucero-palau@amd.com wrote: > From: Alejandro Lucero > > CXL region creation involves allocating capacity from device DPA > (device-physical-address space) and assigning it to decode a given HPA > (host-physical-address space). Before determining how much DPA to > allocate the amount of available HPA must be determined. Also, not all > HPA is created equal, some specifically targets RAM, some target PMEM, > some is prepared for device-memory flows like HDM-D and HDM-DB, and some > is host-only (HDM-H). > > Wrap all of those concerns into an API that retrieves a root decoder > (platform CXL window) that fits the specified constraints and the > capacity available for a new region. > > Add a complementary function for releasing the reference to such root > decoder. > > Based on https://lore.kernel.org/linux-cxl/168592159290.1948938.13522227102445462976.stgit@dwillia2-xfh.jf.intel.com/ > > Signed-off-by: Alejandro Lucero One trivial comment inline. Reviewed-by: Jonathan Cameron > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 80caaf14d08a..0a9eab4f8e2e 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > +static int find_max_hpa(struct device *dev, void *data) > +{ > + struct cxlrd_max_context *ctx = data; > + struct cxl_switch_decoder *cxlsd; > + struct cxl_root_decoder *cxlrd; > + struct resource *res, *prev; > + struct cxl_decoder *cxld; > + resource_size_t max; > + int found = 0; > + > + if (!is_root_decoder(dev)) > + return 0; > + > + cxlrd = to_cxl_root_decoder(dev); > + cxlsd = &cxlrd->cxlsd; > + cxld = &cxlsd->cxld; > + > + /* > + * None flags are declared as bitmaps but for the sake of better code None? > + * used here as such, restricting the bitmap size to those bits used by > + * any Type2 device driver requester. > + */