From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x234.google.com (mail-oi0-x234.google.com [IPv6:2607:f8b0:4003:c06::234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 391211A1E05 for ; Mon, 10 Oct 2016 09:24:28 -0700 (PDT) Received: by mail-oi0-x234.google.com with SMTP id d132so133060439oib.2 for ; Mon, 10 Oct 2016 09:24:28 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20161010063215.24jukvont5ctansy@hz-desktop> References: <20161010003523.4423-1-haozhong.zhang@intel.com> <20161010063215.24jukvont5ctansy@hz-desktop> From: Dan Williams Date: Mon, 10 Oct 2016 09:24:26 -0700 Message-ID: Subject: Re: [RFC KERNEL PATCH 0/2] Add Dom0 NVDIMM support for Xen List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams , "linux-nvdimm@lists.01.org" , xen-devel@lists.xenproject.org, Xiao Guangrong , Konrad Rzeszutek Wilk , Ross Zwisler , Boris Ostrovsky , David Vrabel , Juergen Gross , Andrew Morton , Johannes Thumshirn , Arnd Bergmann , Stefano Stabellini , "linux-kernel@vger.kernel.org" List-ID: On Sun, Oct 9, 2016 at 11:32 PM, Haozhong Zhang wrote: > On 10/09/16 20:45, Dan Williams wrote: >> On Sun, Oct 9, 2016 at 5:35 PM, Haozhong Zhang wrote: >> > Overview >> > ======== >> > This RFC kernel patch series along with corresponding patch series of >> > Xen, QEMU and ndctl implements Xen vNVDIMM, which can map the host >> > NVDIMM devices to Xen HVM domU as vNVDIMM devices. >> > >> > Xen hypervisor does not include an NVDIMM driver, so it needs the >> > assistance from the driver in Dom0 Linux kernel to manage NVDIMM >> > devices. We currently only supports NVDIMM devices in pmem mode. >> > >> > Design and Implementation >> > ========================= >> > The complete design can be found at >> > https://lists.xenproject.org/archives/html/xen-devel/2016-07/msg01921.html. >> >> The KVM enabling for persistent memory does not need this support from >> the kernel, and as far as I can see neither does Xen. If the >> hypervisor needs to reserve some space it can simply trim the amount >> that it hands to the guest. >> > > Xen does not have the NVDIMM driver, so it cannot operate on NVDIMM > devices by itself. Instead it relies on the driver in Dom0 Linux to > probe NVDIMM and make the reservation. I'm missing something because the design document talks about mmap'ing files on a DAX filesystem. So, I'm assuming it is similar to the KVM NVDIMM virtualization case where an mmap range in dom0 is translated into a guest physical range. The suggestion is to reserve some memory out of that mapping rather than introduce a new info block / reservation type to the sub-system. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753345AbcJJQYa (ORCPT ); Mon, 10 Oct 2016 12:24:30 -0400 Received: from mail-oi0-f51.google.com ([209.85.218.51]:33409 "EHLO mail-oi0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752637AbcJJQY2 (ORCPT ); Mon, 10 Oct 2016 12:24:28 -0400 MIME-Version: 1.0 In-Reply-To: <20161010063215.24jukvont5ctansy@hz-desktop> References: <20161010003523.4423-1-haozhong.zhang@intel.com> <20161010063215.24jukvont5ctansy@hz-desktop> From: Dan Williams Date: Mon, 10 Oct 2016 09:24:26 -0700 Message-ID: Subject: Re: [RFC KERNEL PATCH 0/2] Add Dom0 NVDIMM support for Xen To: Dan Williams , "linux-nvdimm@lists.01.org" , xen-devel@lists.xenproject.org, Xiao Guangrong , Konrad Rzeszutek Wilk , Ross Zwisler , Boris Ostrovsky , David Vrabel , Juergen Gross , Andrew Morton , Johannes Thumshirn , Arnd Bergmann , Stefano Stabellini , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Oct 9, 2016 at 11:32 PM, Haozhong Zhang wrote: > On 10/09/16 20:45, Dan Williams wrote: >> On Sun, Oct 9, 2016 at 5:35 PM, Haozhong Zhang wrote: >> > Overview >> > ======== >> > This RFC kernel patch series along with corresponding patch series of >> > Xen, QEMU and ndctl implements Xen vNVDIMM, which can map the host >> > NVDIMM devices to Xen HVM domU as vNVDIMM devices. >> > >> > Xen hypervisor does not include an NVDIMM driver, so it needs the >> > assistance from the driver in Dom0 Linux kernel to manage NVDIMM >> > devices. We currently only supports NVDIMM devices in pmem mode. >> > >> > Design and Implementation >> > ========================= >> > The complete design can be found at >> > https://lists.xenproject.org/archives/html/xen-devel/2016-07/msg01921.html. >> >> The KVM enabling for persistent memory does not need this support from >> the kernel, and as far as I can see neither does Xen. If the >> hypervisor needs to reserve some space it can simply trim the amount >> that it hands to the guest. >> > > Xen does not have the NVDIMM driver, so it cannot operate on NVDIMM > devices by itself. Instead it relies on the driver in Dom0 Linux to > probe NVDIMM and make the reservation. I'm missing something because the design document talks about mmap'ing files on a DAX filesystem. So, I'm assuming it is similar to the KVM NVDIMM virtualization case where an mmap range in dom0 is translated into a guest physical range. The suggestion is to reserve some memory out of that mapping rather than introduce a new info block / reservation type to the sub-system.