From mboxrd@z Thu Jan 1 00:00:00 1970 From: Haozhong Zhang Subject: Re: [PATCH 2/2] pc-nvdimm acpi: build ACPI tables for pc-nvdimm devices Date: Tue, 5 Jan 2016 22:01:26 +0800 Message-ID: <20160105140126.GA29472@hz-desktop.sh.intel.com> References: <1451388527-18009-1-git-send-email-haozhong.zhang@intel.com> <1451388527-18009-3-git-send-email-haozhong.zhang@intel.com> <20160104211055.GA23242@char.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Stefano Stabellini Cc: Wei Liu , xen-devel@lists.xensource.com, Xiao Guangrong , Eduardo Habkost , Andrew Cooper , "Michael S. Tsirkin" , Ian Jackson , Igor Mammedov , Jan Beulich , Paolo Bonzini , Anthony.Perard@citrix.com, Keir Fraser , Ian Campbell , Richard Henderson List-Id: xen-devel@lists.xenproject.org On 01/05/16 11:00, Stefano Stabellini wrote: > On Mon, 4 Jan 2016, Konrad Rzeszutek Wilk wrote: > > On Mon, Jan 04, 2016 at 04:01:08PM +0000, Stefano Stabellini wrote: > > > CC'ing the Xen tools maintainers and Anthony. > > > > > > On Tue, 29 Dec 2015, Haozhong Zhang wrote: > > > > Reuse existing NVDIMM ACPI code to build ACPI tables for pc-nvdimm > > > > devices. The resulting tables are then copied into Xen guest domain so > > > > tha they can be later loaded by Xen hvmloader. > > > > > > > > Signed-off-by: Haozhong Zhang > > > > > > How much work would it be to generate the nvdimm acpi tables from the > > > Xen toolstack? > > > > Why duplicate the code? The QEMU generates the NFIT tables and its sub-tables. > > > > > > > Getting the tables from QEMU doesn't seem like a good idea to me, unless > > > we start getting the whole set of ACPI tables that way. > > > > There is also the ACPI DSDT code - which requires an memory region > > to be reserved for the AML code to drop the parameters so that QEMU > > can scan the NVDIMM for failures. The region (and size) should be > > determined by QEMU since it works on this data. > > QEMU can generate the whole set of ACPI tables. Why should we take only > the nvdimm tables and not the others? > NVDIMM tables are the only tables required to support vNVDIMM in this patch series, and they are self-contained and not conflict with other existing tables built by hvmloader. For other tables built by QEMU, I have no idea whether they could work with Xen, so I only take nvdimm tables from QEMU. > I don't think it is wise to have two components which both think are in > control of generating ACPI tables, hvmloader (soon to be the toolstack > with Anthony's work) and QEMU. From an architectural perspective, it > doesn't look robust to me. > Do you mean whenever nvdimm code in QEMU is changed, we would have to make more efforts to ensure it still works with Xen? > Could we take this opportunity to switch to QEMU generating the whole > set of ACPI tables? > Not quite sure how much effort would be taken on this change. CCed hvmloader maintainers for their comments. Thanks, Haozhong