From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55646) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c2E7h-00088Q-Vi for qemu-devel@nongnu.org; Thu, 03 Nov 2016 05:15:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c2E7e-000421-Ph for qemu-devel@nongnu.org; Thu, 03 Nov 2016 05:15:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35656) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c2E7e-00041G-AX for qemu-devel@nongnu.org; Thu, 03 Nov 2016 05:15:46 -0400 Date: Thu, 3 Nov 2016 10:15:41 +0100 From: Igor Mammedov Message-ID: <20161103101541.1740c0da@nial.brq.redhat.com> In-Reply-To: References: <1477672540-27952-1-git-send-email-guangrong.xiao@linux.intel.com> <1477672540-27952-4-git-send-email-guangrong.xiao@linux.intel.com> <20161101172436.49016997@nial.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v3 3/4] nvdimm acpi: introduce _FIT List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiao Guangrong Cc: pbonzini@redhat.com, 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 On Wed, 2 Nov 2016 23:40:56 +0800 Xiao Guangrong wrote: > On 11/02/2016 12:24 AM, Igor Mammedov wrote: > > On Sat, 29 Oct 2016 00:35:39 +0800 > > Xiao Guangrong wrote: > > =20 > >> _FIT is required for hotplug support, guest will inquire the updated > >> device info from it if a hotplug event is received > >> > >> As FIT buffer is not completely mapped into guest address space, so a > >> new function, Read FIT whose UUID is UUID > >> 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62, handle 0x10000, function index > >> is 0x1, is reserved by QEMU to read the piece of FIT buffer. The buffer > >> is concatenated before _FIT return > >> > >> Refer to docs/specs/acpi-nvdimm.txt for detailed design > >> > >> Signed-off-by: Xiao Guangrong > >> --- > >> docs/specs/acpi_nvdimm.txt | 58 ++++++++++++- > >> hw/acpi/nvdimm.c | 204 ++++++++++++++++++++++++++++++++++++= ++++++++- > >> 2 files changed, 257 insertions(+), 5 deletions(-) > >> > >> diff --git a/docs/specs/acpi_nvdimm.txt b/docs/specs/acpi_nvdimm.txt > >> index 0fdd251..4aa5e3d 100644 > >> --- a/docs/specs/acpi_nvdimm.txt > >> +++ b/docs/specs/acpi_nvdimm.txt > >> @@ -127,6 +127,58 @@ _DSM process diagram: > >> | result from the page | | | > >> +--------------------------+ +--------------+ > >> > >> - _FIT implementation > >> - ------------------- > >> - TODO (will fill it when nvdimm hotplug is introduced) > >> +Device Handle Reservation > >> +------------------------- > >> +As we mentioned above, byte 0 ~ byte 3 in the DSM memory save NVDIMM = device > >> +handle. The handle is completely QEMU internal thing, the values in r= ange > >> +[0, 0xFFFF] indicate nvdimm device (O means nvdimm root device named = NVDR), > >> +other values are reserved by other purpose. > >> + > >> +Current reserved handle: > >> +0x10000 is reserved for QEMU internal DSM function called on the root > >> +device. =20 > > Above part should go to section where 'handle' is defined, i.e. earlier= in the file: > > > > 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. > > =20 >=20 > Okay. >=20 > > =20 > >> +QEMU internal use only _DSM function > >> +------------------------------------ > >> +UUID, 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62, is reserved for QEMU inte= rnal > >> +DSM function. > >> + > >> +There is the function introduced by QEMU and only used by QEMU intern= al. > >> + > >> +1) Read FIT =20 > > UUID 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62 is reserved for Read_FIT DSM = function > > (private QEMU function) > > =20 >=20 > okay. >=20 > >> + As we only reserved one page for NVDIMM ACPI it is impossible to m= ap 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. =20 > > _FIT method uses Read_FIT function to fetch NFIT structures blob from = QEMU > > in 1 page sized increments which are then concatenated and returned as= _FIT method result. > > =20 >=20 > okay. >=20 > > =20 > >> + > >> + Input parameters: > >> + Arg0 =E2=80=93 UUID {set to 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62} > >> + Arg1 =E2=80=93 Revision ID (set to 1) > >> + Arg2 - Function Index, 0x1 > >> + Arg3 - A package containing a buffer whose layout is as follows: > >> + > >> + +----------+-------------+-------------+--------------------------= ---------+ > >> + | Filed | Byte Length | Byte Offset | Description = | =20 > > ^ field, s/Byte//, s/Byte// =20 > >> + +----------+-------------+-------------+--------------------------= ---------+ > >> + | offset | 4 | 0 | the offset of FIT buffer = | =20 > > offset in QEMU's NFIT structures blob to read from =20 >=20 > okay. >=20 > > =20 > >> + +----------+-------------+-------------+--------------------------= ---------+ > >> + > >> + Output: > >> + +----------+-------------+-------------+--------------------------= ---------+ > >> + | Filed | Byte Length | Byte Offset | Description = | > >> + +----------+-------------+-------------+--------------------------= ---------+ > >> + | | | | return status codes = | > >> + | | | | 0x100 indicates fit has= been | > >> + | status | 4 | 0 | updated = | =20 > > 0x100 - error caused by NFIT update while read by _FIT wasn't completed= =20 >=20 > okay. >=20 > > =20 > >> + | | | | other follows Chapter 3 i= n DSM | =20 > > s/other follows/other codes follow/ =20 >=20 > okay. >=20 > > =20 > >> + | | | | Spec Rev1 = | > >> + +----------+-------------+-------------+--------------------------= ---------+ > >> + | fit data | Varies | 4 | FIT data = | > >> + | | | | = | > >> + +----------+-------------+-------------+--------------------------= ---------+ =20 > > what does "Varies" mean, how would I know reading this how much data Re= ad_FIT should read > > from shared page? =20 >=20 > I mean other bytes in the buffer returned by this function except the 'st= atus' field > will be used as fit data. Maybe it is has a 'length' field? you fill in length in C and access it in AML code and it's a part of output= buffer format so document it properly here. >=20 > > =20 > >> + > >> + The FIT offset is maintained by the caller itself, =20 > > probably is not necessary sentence, or specify a caller (for example OS= PM) > > =20 >=20 > Okay. >=20 > >> current offset plugs =20 > > ^^^^? =20 >=20 > Typo. should be plus. >=20 > > =20 > >> + the length returned by the function is the next offset we should r= ead. > >> + When all the FIT data has been read out, zero length is returned. > >> + > >> + If it returns 0x100, OSPM should restart to read FIT (read from of= fset 0 > >> + again). =20 > > [...] > > that's all for doc part, I'll do the code part later. > > =20 >=20 > Thank you, Igor. >=20