From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH 4/4] hvmloader: add support to load extra ACPI tables from qemu Date: Tue, 19 Jan 2016 04:46:51 -0700 Message-ID: <569E303B02000078000C87A2@prv-mh.provo.novell.com> References: <1451388711-18646-1-git-send-email-haozhong.zhang@intel.com> <1451388711-18646-5-git-send-email-haozhong.zhang@intel.com> <5699362402000078000C7803@prv-mh.provo.novell.com> <20160118005255.GC3528@hz-desktop.sh.intel.com> <569CB47502000078000C7CFB@prv-mh.provo.novell.com> <20160119113722.GU1691@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160119113722.GU1691@citrix.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Wei Liu Cc: Haozhong Zhang , Kevin Tian , Keir Fraser , Ian Campbell , StefanoStabellini , Andrew Cooper , Ian Jackson , xen-devel@lists.xen.org, Jun Nakajima List-Id: xen-devel@lists.xenproject.org >>> On 19.01.16 at 12:37, wrote: > On Mon, Jan 18, 2016 at 01:46:29AM -0700, Jan Beulich wrote: >> >>> On 18.01.16 at 01:52, wrote: >> > On 01/15/16 10:10, Jan Beulich wrote: >> >> >>> On 29.12.15 at 12:31, wrote: >> >> > NVDIMM devices are detected and configured by software through >> >> > ACPI. Currently, QEMU maintains ACPI tables of vNVDIMM devices. This >> >> > patch extends the existing mechanism in hvmloader of loading passthrough >> >> > ACPI tables to load extra ACPI tables built by QEMU. >> >> >> >> Mechanically the patch looks okay, but whether it's actually needed >> >> depends on whether indeed we want NV RAM managed in qemu >> >> instead of in the hypervisor (where imo it belongs); I didn' see any >> >> reply yet to that same comment of mine made (iirc) in the context >> >> of another patch. >> > >> > One purpose of this patch series is to provide vNVDIMM backed by host >> > NVDIMM devices. It requires some drivers to detect and manage host >> > NVDIMM devices (including parsing ACPI, managing labels, etc.) that >> > are not trivial, so I leave this work to the dom0 linux. Current Linux >> > kernel abstract NVDIMM devices as block devices (/dev/pmemXX). QEMU >> > then mmaps them into certain range of dom0's address space and asks >> > Xen hypervisor to map that range of address space to a domU. >> > > > OOI Do we have a viable solution to do all these non-trivial things in > core hypervisor? Are you proposing designing a new set of hypercalls > for NVDIMM? That's certainly a possibility; I lack sufficient detail to make myself an opinion which route is going to be best. Jan