From patchwork Fri Oct 30 05:56:16 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 7524021 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 369ACBEEA4 for ; Fri, 30 Oct 2015 06:02:57 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 296612082B for ; Fri, 30 Oct 2015 06:02:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E545E20820 for ; Fri, 30 Oct 2015 06:02:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758627AbbJ3GCt (ORCPT ); Fri, 30 Oct 2015 02:02:49 -0400 Received: from mga11.intel.com ([192.55.52.93]:20541 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758604AbbJ3GCn (ORCPT ); Fri, 30 Oct 2015 02:02:43 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP; 29 Oct 2015 23:02:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,217,1444719600"; d="scan'208";a="590814196" Received: from xiaoreal1.sh.intel.com (HELO xiaoreal1.sh.intel.com.sh.intel.com) ([10.239.48.79]) by FMSMGA003.fm.intel.com with ESMTP; 29 Oct 2015 23:02:40 -0700 From: Xiao Guangrong To: pbonzini@redhat.com, imammedo@redhat.com Cc: gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com, mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com, dan.j.williams@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, Xiao Guangrong Subject: [PATCH v6 22/33] docs: add NVDIMM ACPI documentation Date: Fri, 30 Oct 2015 13:56:16 +0800 Message-Id: <1446184587-142784-23-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1446184587-142784-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1446184587-142784-1-git-send-email-guangrong.xiao@linux.intel.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It describes the basic concepts of NVDIMM ACPI and the interface between QEMU and the ACPI BIOS Signed-off-by: Xiao Guangrong --- docs/specs/acpi_nvdimm.txt | 179 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 179 insertions(+) create mode 100644 docs/specs/acpi_nvdimm.txt diff --git a/docs/specs/acpi_nvdimm.txt b/docs/specs/acpi_nvdimm.txt new file mode 100644 index 0000000..cc5db2c --- /dev/null +++ b/docs/specs/acpi_nvdimm.txt @@ -0,0 +1,179 @@ +QEMU<->ACPI BIOS NVDIMM interface +--------------------------------- + +QEMU supports NVDIMM via ACPI. This document describes the basic concepts of +NVDIMM ACPI and the interface between QEMU and the ACPI BIOS. + +NVDIMM ACPI Background +---------------------- +NVDIMM is introduced in ACPI 6.0 which defines an NVDIMM root device under +_SB scope with a _HID of “ACPI0012”. For each NVDIMM present or intended +to be supported by platform, platform firmware also exposes an ACPI +Namespace Device under the root device. + +The NVDIMM child devices under the NVDIMM root device are defined with _ADR +corresponding to the NFIT device handle. The NVDIMM root device and the +NVDIMM devices can have device specific methods (_DSM) to provide additional +functions specific to a particular NVDIMM implementation. + +This is an example from ACPI 6.0, a platform contains one NVDIMM: + +Scope (\_SB){ + Device (NVDR) // Root device + { + Name (_HID, “ACPI0012”) + Method (_STA) {...} + Method (_FIT) {...} + Method (_DSM, ...) {...} + Device (NVD) + { + Name(_ADR, h) //where h is NFIT Device Handle for this NVDIMM + Method (_DSM, ...) {...} + } + } +} + +Methods supported on both NVDIMM root device and NVDIMM device are +1) _STA(Status) + It returns the current status of a device, which can be one of the + following: enabled, disabled, or removed. + + Arguments: None + + Return Value: + It returns an An Integer which is defined as followings: + Bit [0] – Set if the device is present. + Bit [1] – Set if the device is enabled and decoding its resources. + Bit [2] – Set if the device should be shown in the UI. + Bit [3] – Set if the device is functioning properly (cleared if device + failed its diagnostics). + Bit [4] – Set if the battery is present. + Bits [31:5] – Reserved (must be cleared). + +2) _DSM (Device Specific Method) + It is a control method that enables devices to provide device specific + control functions that are consumed by the device driver. + The NVDIMM DSM specification can be found at: + http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf + + Arguments: + Arg0 – A Buffer containing a UUID (16 Bytes) + Arg1 – An Integer containing the Revision ID (4 Bytes) + Arg2 – An Integer containing the Function Index (4 Bytes) + Arg3 – A package containing parameters for the function specified by the + UUID, Revision ID, and Function Index + + Return Value: + If Function Index = 0, a Buffer containing a function index bitfield. + Otherwise, the return value and type depends on the UUID, revision ID + and function index which are described in the DSM specification. + +Methods on NVDIMM ROOT Device +_FIT(Firmware Interface Table) + It evaluates to a buffer returning data in the format of a series of NFIT + Type Structure. + + Arguments: None + + Return Value: + A Buffer containing a list of NFIT Type structure entries. + + The detailed definition of the structure can be found at ACPI 6.0: 5.2.25 + NVDIMM Firmware Interface Table (NFIT). + +QEMU NVDIMM Implemention +======================== +QEMU reserves a page starting from 0xFF00000 and 4 bytes IO Port starting +from 0x0a18 for NVDIMM ACPI. + +Memory 0xFF00000 - 0xFF00FFF: + This page is RAM-based and it is used to transfer data between _DSM + method and QEMU. If ACPI has control, this pages is owned by ACPI which + writes _DSM input data to it, otherwise, it is owned by QEMU which + emulates _DSM access and writes the output data to it. + + ACPI Writes _DSM Input Data: + [0xFF00000 - 0xFF00003]: 4 bytes, NVDIMM Devcie Handle, 0 is reserved + for NVDIMM Root device. + [0xFF00004 - 0xFF00007]: 4 bytes, Revision ID, that is the Arg1 of _DSM + method. + [0xFF00008 - 0xFF0000B]: 4 bytes. Function Index, that is the Arg2 of + _DSM method. + [0xFF0000C - 0xFF00FFF]: 4084 bytes, the Arg3 of _DSM method + + QEMU Writes Output Data: + [0xFF00000 - 0xFF00FFF]: the DSM return result filled by QEMU + +IO Port 0x0a18 - 0xa1b: + ACPI uses it to transfer control from guest to QEMU and read the size + of return result filled by QEMU + + Read Access: + [0x0a18 - 0xa1b]: 4 bytes, the buffer size of _DSM output data. + +_DSM process diagram: +--------------------- +The page, 0xFF00000 - 0xFF00FFF, is used by _DSM Virtualization. + + +----------------------+?? +-----------------------+ +?|?? 1.?OSPM?? |??????| 2. OSPM | +?|?save _DSM input data | | read 0x0a18 | Exit to QEMU +?| to the page +----->| +------------+ +?| | | | | +?+----------------------+ +-----------------------+ | +? | +? v +?+------------- ----+ +-----------+ +------------------+--------+ +?| 5 QEMU | | 4 QEMU | | 3. QEMU | +?| write _DSM result | | emulate | | get _DSM input parameters | + | to the page +<------+ _DSM +<-----+ from the page | +?| | | | | | + +--------+-----------+ +-----------+ +---------------------------+ + | + | Enter Guest + | + v + +--------------------------+ +--------------+ + | 6 OSPM | | 7 OSPM | + | result size is returned | | _DSM return | + | by read and get DSM +----->+ | + | result from the page | | | + +--------------------------+ +--------------+ + + QEMU internal use only _DSM function + ------------------------------------ + There is the function introduced by QEMU and only used by QEMU internal. + + 1) Read FIT + As we only reserved one page for NVDIMM ACPI it is impossible to map the + whole FIT data to guest's address space. This function is used by _FIT + method to read a piece of FIT data from QEMU. + + Input parameters: + Arg0 – UUID {set to 2f10e7a4-9e91-11e4-89d3-123b93f75cba} + Arg1 – Revision ID (set to 1) + Arg2 - 0xFFFFFFFF + Arg3 - A package containing a buffer whose layout is as follows: + + +----------+-------------+-------------+-----------------------------------+ + | Filed | Byte Length | Byte Offset | Description | + +----------+-------------+-------------+-----------------------------------+ + | offset | 4 | 0 | the offset of FIT buffer | + +----------+-------------+-------------+-----------------------------------+ + + Output: + +----------+-------------+-------------+-----------------------------------+ + | Filed | Byte Length | Byte Offset | Description | + +----------+-------------+-------------+-----------------------------------+ + | status | 4 | 0 | return status codes following | + | | | | Chapter 3 in DSM Spec Rev1 | + +----------+-------------+-------------+-----------------------------------+ + | length | 4 | 4 | the length of FIT buffer read out | + +----------+-------------+-------------+-----------------------------------+ + | fit data | Varies | 8 | FIT data, its size is indicated | + | | | | by length field above | + +----------+-------------+-------------+-----------------------------------+ + + The FIT offset is maintained by the caller itself, current offset plugs + the length returned by the function is the next offset we should read. + When all the FIT data has been read out, zero length is returned.