From: "Jan Beulich" <JBeulich@suse.com>
To: Haozhong Zhang <haozhong.zhang@intel.com>
Cc: Juergen Gross <JGross@suse.com>,
Kevin Tian <kevin.tian@intel.com>, Wei Liu <wei.liu2@citrix.com>,
Ian Campbell <ian.campbell@citrix.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
George Dunlap <George.Dunlap@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
xen-devel@lists.xen.org, Jun Nakajima <jun.nakajima@intel.com>,
Xiao Guangrong <guangrong.xiao@linux.intel.com>,
Keir Fraser <keir@xen.org>
Subject: Re: [RFC Design Doc] Add vNVDIMM support for Xen
Date: Wed, 24 Feb 2016 09:54:19 -0700 [thread overview]
Message-ID: <56CDEE4B02000078000D5DAD@prv-mh.provo.novell.com> (raw)
In-Reply-To: <20160224154833.GB10229@hz-desktop.sh.intel.com>
>>> On 24.02.16 at 16:48, <haozhong.zhang@intel.com> wrote:
> On 02/24/16 07:24, Jan Beulich wrote:
>> >>> On 24.02.16 at 14:28, <haozhong.zhang@intel.com> wrote:
>> > On 02/18/16 10:17, Jan Beulich wrote:
>> >> >>> On 01.02.16 at 06:44, <haozhong.zhang@intel.com> wrote:
>> >> > 3.3 Guest ACPI Emulation
>> >> >
>> >> > 3.3.1 My Design
>> >> >
>> >> > Guest ACPI emulation is composed of two parts: building guest NFIT
>> >> > and SSDT that defines ACPI namespace devices for NVDIMM, and
>> >> > emulating guest _DSM.
>> >> >
>> >> > (1) Building Guest ACPI Tables
>> >> >
>> >> > This design reuses and extends hvmloader's existing mechanism that
>> >> > loads passthrough ACPI tables from binary files to load NFIT and
>> >> > SSDT tables built by QEMU:
>> >> > 1) Because the current QEMU does not building any ACPI tables when
>> >> > it runs as the Xen device model, this design needs to patch QEMU
>> >> > to build NFIT and SSDT (so far only NFIT and SSDT) in this case.
>> >> >
>> >> > 2) QEMU copies NFIT and SSDT to the end of guest memory below
>> >> > 4G. The guest address and size of those tables are written into
>> >> > xenstore (/local/domain/domid/hvmloader/dm-acpi/{address,length}).
>> >> >
>> >> > 3) hvmloader is patched to probe and load device model passthrough
>> >> > ACPI tables from above xenstore keys. The detected ACPI tables
>> >> > are then appended to the end of existing guest ACPI tables just
>> >> > like what current construct_passthrough_tables() does.
>> >> >
>> >> > Reasons for this design are listed below:
>> >> > - NFIT and SSDT in question are quite self-contained, i.e. they do
>> >> > not refer to other ACPI tables and not conflict with existing
>> >> > guest ACPI tables in Xen. Therefore, it is safe to copy them from
>> >> > QEMU and append to existing guest ACPI tables.
>> >>
>> >> How is this not conflicting being guaranteed? In particular I don't
>> >> see how tables containing AML code and coming from different
>> >> sources won't possibly cause ACPI name space collisions.
>> >>
>> >
>> > Really there is no effective mechanism to avoid ACPI name space
>> > collisions (and other kinds of conflicts) between ACPI tables loaded
>> > from QEMU and ACPI tables built by hvmloader. Because which ACPI tables
>> > are loaded is determined by developers, IMO it's developers'
>> > responsibility to avoid any collisions and conflicts with existing ACPI
>> > tables.
>>
>> Right, but this needs to be spelled out and settled on at design
>> time (i.e. now), rather leaving things unspecified, awaiting the
>> first clash.
>
> So that means if no collision-proof mechanism is introduced, Xen should not
> trust any passed-in ACPI tables and should build them by itself?
Basically yes, albeit collision-proof may be too much to demand.
Simply separating name spaces (for hvmloader and qemu to have
their own sub-spaces) would be sufficient imo. We should trust
ourselves to play by such a specification.
Jan
next prev parent reply other threads:[~2016-02-24 16:54 UTC|newest]
Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-01 5:44 [RFC Design Doc] Add vNVDIMM support for Xen Haozhong Zhang
2016-02-01 18:25 ` Andrew Cooper
2016-02-02 3:27 ` Tian, Kevin
2016-02-02 3:44 ` Haozhong Zhang
2016-02-02 11:09 ` Andrew Cooper
2016-02-02 6:33 ` Tian, Kevin
2016-02-02 7:39 ` Zhang, Haozhong
2016-02-02 7:48 ` Tian, Kevin
2016-02-02 7:53 ` Zhang, Haozhong
2016-02-02 8:03 ` Tian, Kevin
2016-02-02 8:49 ` Zhang, Haozhong
2016-02-02 19:01 ` Konrad Rzeszutek Wilk
2016-02-02 17:11 ` Stefano Stabellini
2016-02-03 7:00 ` Haozhong Zhang
2016-02-03 9:13 ` Jan Beulich
2016-02-03 14:09 ` Andrew Cooper
2016-02-03 14:23 ` Haozhong Zhang
2016-02-05 14:40 ` Ross Philipson
2016-02-06 1:43 ` Haozhong Zhang
2016-02-06 16:17 ` Ross Philipson
2016-02-03 12:02 ` Stefano Stabellini
2016-02-03 13:11 ` Haozhong Zhang
2016-02-03 14:20 ` Andrew Cooper
2016-02-04 3:10 ` Haozhong Zhang
2016-02-03 15:16 ` George Dunlap
2016-02-03 15:22 ` Stefano Stabellini
2016-02-03 15:35 ` Konrad Rzeszutek Wilk
2016-02-03 15:35 ` George Dunlap
2016-02-04 2:55 ` Haozhong Zhang
2016-02-04 12:24 ` Stefano Stabellini
2016-02-15 3:16 ` Zhang, Haozhong
2016-02-16 11:14 ` Stefano Stabellini
2016-02-16 12:55 ` Jan Beulich
2016-02-17 9:03 ` Haozhong Zhang
2016-03-04 7:30 ` Haozhong Zhang
2016-03-16 12:55 ` Haozhong Zhang
2016-03-16 13:13 ` Konrad Rzeszutek Wilk
2016-03-16 13:16 ` Jan Beulich
2016-03-16 13:55 ` Haozhong Zhang
2016-03-16 14:23 ` Jan Beulich
2016-03-16 14:55 ` Haozhong Zhang
2016-03-16 15:23 ` Jan Beulich
2016-03-17 8:58 ` Haozhong Zhang
2016-03-17 11:04 ` Jan Beulich
2016-03-17 12:44 ` Haozhong Zhang
2016-03-17 12:59 ` Jan Beulich
2016-03-17 13:29 ` Haozhong Zhang
2016-03-17 13:52 ` Jan Beulich
2016-03-17 14:00 ` Ian Jackson
2016-03-17 14:21 ` Haozhong Zhang
2016-03-29 8:47 ` Haozhong Zhang
2016-03-29 9:11 ` Jan Beulich
2016-03-29 10:10 ` Haozhong Zhang
2016-03-29 10:49 ` Jan Beulich
2016-04-08 5:02 ` Haozhong Zhang
2016-04-08 15:52 ` Jan Beulich
2016-04-12 8:45 ` Haozhong Zhang
2016-04-21 5:09 ` Haozhong Zhang
2016-04-21 7:04 ` Jan Beulich
2016-04-22 2:36 ` Haozhong Zhang
2016-04-22 8:24 ` Jan Beulich
2016-04-22 10:16 ` Haozhong Zhang
2016-04-22 10:53 ` Jan Beulich
2016-04-22 12:26 ` Haozhong Zhang
2016-04-22 12:36 ` Jan Beulich
2016-04-22 12:54 ` Haozhong Zhang
2016-04-22 13:22 ` Jan Beulich
2016-03-17 13:32 ` Konrad Rzeszutek Wilk
2016-02-03 15:47 ` Konrad Rzeszutek Wilk
2016-02-04 2:36 ` Haozhong Zhang
2016-02-15 9:04 ` Zhang, Haozhong
2016-02-02 19:15 ` Konrad Rzeszutek Wilk
2016-02-03 8:28 ` Haozhong Zhang
2016-02-03 9:18 ` Jan Beulich
2016-02-03 12:22 ` Haozhong Zhang
2016-02-03 12:38 ` Jan Beulich
2016-02-03 12:49 ` Haozhong Zhang
2016-02-03 14:30 ` Andrew Cooper
2016-02-03 14:39 ` Jan Beulich
2016-02-15 8:43 ` Haozhong Zhang
2016-02-15 11:07 ` Jan Beulich
2016-02-17 9:01 ` Haozhong Zhang
2016-02-17 9:08 ` Jan Beulich
2016-02-18 7:42 ` Haozhong Zhang
2016-02-19 2:14 ` Konrad Rzeszutek Wilk
2016-03-01 7:39 ` Haozhong Zhang
2016-03-01 18:33 ` Ian Jackson
2016-03-01 18:49 ` Konrad Rzeszutek Wilk
2016-03-02 7:14 ` Haozhong Zhang
2016-03-02 13:03 ` Jan Beulich
2016-03-04 2:20 ` Haozhong Zhang
2016-03-08 9:15 ` Haozhong Zhang
2016-03-08 9:27 ` Jan Beulich
2016-03-09 12:22 ` Haozhong Zhang
2016-03-09 16:17 ` Jan Beulich
2016-03-10 3:27 ` Haozhong Zhang
2016-03-17 11:05 ` Ian Jackson
2016-03-17 13:37 ` Haozhong Zhang
2016-03-17 13:56 ` Jan Beulich
2016-03-17 14:22 ` Haozhong Zhang
2016-03-17 14:12 ` Xu, Quan
2016-03-17 14:22 ` Zhang, Haozhong
2016-03-07 20:53 ` Konrad Rzeszutek Wilk
2016-03-08 5:50 ` Haozhong Zhang
2016-02-18 17:17 ` Jan Beulich
2016-02-24 13:28 ` Haozhong Zhang
2016-02-24 14:00 ` Ross Philipson
2016-02-24 16:42 ` Haozhong Zhang
2016-02-24 17:50 ` Ross Philipson
2016-02-24 14:24 ` Jan Beulich
2016-02-24 15:48 ` Haozhong Zhang
2016-02-24 16:54 ` Jan Beulich [this message]
2016-02-28 14:48 ` Haozhong Zhang
2016-02-29 9:01 ` Jan Beulich
2016-02-29 9:45 ` Haozhong Zhang
2016-02-29 10:12 ` Jan Beulich
2016-02-29 11:52 ` Haozhong Zhang
2016-02-29 12:04 ` Jan Beulich
2016-02-29 12:22 ` Haozhong Zhang
2016-03-01 13:51 ` Ian Jackson
2016-03-01 15:04 ` Jan Beulich
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