From patchwork Wed Oct 28 22:26:20 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 537375 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 2CF2C140E31 for ; Thu, 29 Oct 2015 01:41:27 +1100 (AEDT) Received: from localhost ([::1]:38396 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZrRum-00037R-RY for incoming@patchwork.ozlabs.org; Wed, 28 Oct 2015 10:41:24 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54848) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZrRmM-0005gf-In for qemu-devel@nongnu.org; Wed, 28 Oct 2015 10:32:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZrRmK-0002UL-UH for qemu-devel@nongnu.org; Wed, 28 Oct 2015 10:32:42 -0400 Received: from mga01.intel.com ([192.55.52.88]:15622) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZrRmK-00028A-LK for qemu-devel@nongnu.org; Wed, 28 Oct 2015 10:32:40 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP; 28 Oct 2015 07:32:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,210,1444719600"; d="scan'208";a="589668429" 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; 28 Oct 2015 07:32:38 -0700 From: Xiao Guangrong To: pbonzini@redhat.com, imammedo@redhat.com Date: Wed, 28 Oct 2015 22:26:20 +0000 Message-Id: <1446071191-62591-23-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1446071191-62591-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1446071191-62591-1-git-send-email-guangrong.xiao@linux.intel.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.88 Cc: Xiao Guangrong , ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, dan.j.williams@intel.com, rth@twiddle.net Subject: [Qemu-devel] [PATCH v5 22/33] docs: add NVDIMM ACPI documentation X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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.