From patchwork Fri Jun 17 11:08:16 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 9183519 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1D87160573 for ; Fri, 17 Jun 2016 11:20:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0C9AA27E5A for ; Fri, 17 Jun 2016 11:20:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 00B6B28399; Fri, 17 Jun 2016 11:20:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 489F627E5A for ; Fri, 17 Jun 2016 11:20:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933570AbcFQLT6 (ORCPT ); Fri, 17 Jun 2016 07:19:58 -0400 Received: from mga01.intel.com ([192.55.52.88]:64124 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933516AbcFQLT4 (ORCPT ); Fri, 17 Jun 2016 07:19:56 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP; 17 Jun 2016 04:19:55 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,483,1459839600"; d="scan'208";a="989692476" Received: from xiaoreal1.sh.intel.com (HELO xiaoreal1.sh.intel.com.sh.intel.com) ([10.239.48.133]) by fmsmga001.fm.intel.com with ESMTP; 17 Jun 2016 04:19:55 -0700 From: Xiao Guangrong To: mst@redhat.com Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, Xiao Guangrong Subject: [PATCH v5 13/13] docs: add NVDIMM ACPI documentation Date: Fri, 17 Jun 2016 19:08:16 +0800 Message-Id: <1466161696-99298-14-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1466161696-99298-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1466161696-99298-1-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-Virus-Scanned: ClamAV using ClamSMTP It describes the basic concepts of NVDIMM ACPI and the interfaces between QEMU and the ACPI BIOS Signed-off-by: Xiao Guangrong Reviewed-by: Stefan Hajnoczi Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- docs/specs/acpi_nvdimm.txt | 132 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 132 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..0fdd251 --- /dev/null +++ b/docs/specs/acpi_nvdimm.txt @@ -0,0 +1,132 @@ +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, ...) {...} + } + } +} + +Method supported on both NVDIMM root device and NVDIMM device +_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 uses 4 bytes IO Port starting from 0x0a18 and a RAM-based memory page +for NVDIMM ACPI. + +Memory: + QEMU uses BIOS Linker/loader feature to ask BIOS to allocate a memory + page and dynamically patch its into a int32 object named "MEMA" in ACPI. + + 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 (based on the offset in the page): + [0x0 - 0x3]: 4 bytes, NVDIMM Device Handle, 0 is reserved for NVDIMM + Root device. + [0x4 - 0x7]: 4 bytes, Revision ID, that is the Arg1 of _DSM method. + [0x8 - 0xB]: 4 bytes. Function Index, that is the Arg2 of _DSM method. + [0xC - 0xFFF]: 4084 bytes, the Arg3 of _DSM method. + + QEMU Writes Output Data (based on the offset in the page): + [0x0 - 0x3]: 4 bytes, the length of result + [0x4 - 0xFFF]: 4092 bytes, the DSM result filled by QEMU + +IO Port 0x0a18 - 0xa1b: + ACPI writes the address of the memory page allocated by BIOS to this + port then QEMU gets the control and fills the result in the memory page. + + write Access: + [0x0a18 - 0xa1b]: 4 bytes, the address of the memory page allocated + by BIOS. + +_DSM process diagram: +--------------------- +"MEMA" indicates the address of memory page allocated by BIOS. + + +----------------------+   +-----------------------+ + |   1. OSPM   |      | 2. OSPM | + | save _DSM input data | | write "MEMA" to | Exit to QEMU + | to the page +----->| IO port 0x0a18 +------------+ + | indicated by "MEMA" | | | | + +----------------------+ +-----------------------+ | +  | +  v + +------------- ----+ +-----------+ +------------------+--------+ + | 5 QEMU | | 4 QEMU | | 3. QEMU | + | write _DSM result | | emulate | | get _DSM input data from | + | to the page +<------+ _DSM +<-----+ the page indicated by the | + | | | | | value from the IO port | + +--------+-----------+ +-----------+ +---------------------------+ + | + | Enter Guest + | + v + +--------------------------+ +--------------+ + | 6 OSPM | | 7 OSPM | + | result size is returned | | _DSM return | + | by reading DSM +----->+ | + | result from the page | | | + +--------------------------+ +--------------+ + + _FIT implementation + ------------------- + TODO (will fill it when nvdimm hotplug is introduced)