From patchwork Mon Oct 19 00:54:08 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 7431211 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 5CFBCBEEA4 for ; Sun, 18 Oct 2015 17:00:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5944420628 for ; Sun, 18 Oct 2015 17:00:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EFCB520627 for ; Sun, 18 Oct 2015 17:00:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932262AbbJRRAX (ORCPT ); Sun, 18 Oct 2015 13:00:23 -0400 Received: from mga11.intel.com ([192.55.52.93]:44849 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932253AbbJRRAV (ORCPT ); Sun, 18 Oct 2015 13:00:21 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP; 18 Oct 2015 10:00:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,698,1437462000"; d="scan'208";a="583275873" 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; 18 Oct 2015 10:00:19 -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 v4 22/33] docs: add NVDIMM ACPI documentation Date: Mon, 19 Oct 2015 08:54:08 +0800 Message-Id: <1445216059-88521-23-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1445216059-88521-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1445216059-88521-1-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=-5.0 required=5.0 tests=BAYES_00, DATE_IN_FUTURE_06_12, RCVD_IN_DNSWL_HI, T_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 | 154 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 154 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..feafa93 --- /dev/null +++ b/docs/specs/acpi_nvdimm.txt @@ -0,0 +1,154 @@ +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 the memory region, 0xFF00000 ~ 0xFFF00000, for NVDIMM ACPI. + +0xFF00000 - 0xFF00FFF: + The first page of the region is MMIO-based that means any access in this + region will be emulated by QEMU. ACPU uses it to transfer control from + guest to QEMU. + + Write Access: + [0xFF00000 - 0xFF00003]: 4 bytes, ACPI write 0x99 to it to transfer + control to QEMU. + +0xFF01000 - 0xFF01FFF: + This second page of the region 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: + [0xFF01000 - 0xFF01003]: 4 bytes, NVDIMM Devcie Handle, 0 is reserved + for NVDIMM Root device. + [0xFF01004 - 0xFF01007]: 4 bytes, Revision ID, that is the Arg1 of _DSM + method. + [0xFF01008 - 0xFF0100B]: 4 bytes. Function Index, that is the Arg2 of + _DSM method. + [0xFF0100C - 0xFF01FFF]: 4084 bytes, the Arg3 of _DSM method + + QEMU Writes Output Data + [0xFF01000 - 0xFF01003]: 4 bytes, @buffer-size, see below. + [0xFF01004 - @buffer-size]: the size is depends on the value read from + 0xFF01000 - 0xFF01003. It is the buffer + returned by _DSM + +0xFF02000 - 0xFFF00000: + It is RAM-based mapping. QEMU inquires all the NVDIMM device plugged into + the platform and saves their structures to this region while system is + booting or NVDIMM device is being hot added or removed (not enabled yet). + + _FIT method gets system structure information from this region and returns + it to Guest. + +_DSM process diagram: +--------------------- +The second page in the reserved region, 0xFF01000 - 0xFF01FFF, is used by +_DSM Virtualization. + + +----------------------+?? +-----------------------+ +?|?? 1.?OSPM?? |??????| 2. OSPM | +?|?save _DSM input data | | write 0x99 to | Exit to QEMU +?| to the page +----->| 0xFF00000 - 0xFF00003 +------------+ +?| | | | | +?+----------------------+ +-----------------------+ | +? | +? v +?+------------- ----+ +-----------+ +------------------+--------+ +?| 5 QEMU | | 4 QEMU | | 3. QEMU | +?| write buffer size | | emulate | | get _DSM input parameters | + | and buffer to +<------+ _DSM +<-----+ from the page | +?| the page | | | | | + +--------+-----------+ +-----------+ +---------------------------+ + | + | Enter Guest + | + v + +--------------------------+ +--------------+ + | 6 OSPM | | 7 OSPM | + | get buffer size | | _DSM return | + | and buffer from the page +----->+ | + | | | | + +--------------------------+ +--------------+