Re: [Qemu-devel] [PATCH v3 00/32] implement vNVDIMM

[Igor Mammedov]

On Mon, 12 Oct 2015 11:06:20 +0800
Xiao Guangrong <address@hidden> wrote:

> 
> 
> On 10/12/2015 10:59 AM, Bharata B Rao wrote:
> > Xiao,
> >
> > Are these patches present in any git tree so that they can be easily tried 
> > out.
> >
> 
> Sorry, currently no git tree out of my workspace is available :(
Is it possible for you to put working tree on github?

> 
> BTW, this patchset is based on top of the commit b37686f7e on qemu tree:
> commit b37686f7e84b22cfaf7fd01ac5133f2617cc3027
> Merge: 8be6e62 98cf48f
> Author: Peter Maydell <address@hidden>
> Date:   Fri Oct 9 12:18:13 2015 +0100
> 
>      Merge remote-tracking branch 
> 'remotes/stefanha/tags/tracing-pull-request' into staging
> 
> Thanks.
> 
> > Regards,
> > Bharata.
> >
> > On Sun, Oct 11, 2015 at 9:22 AM, Xiao Guangrong
> > <address@hidden> wrote:
> >> Changelog in v3:
> >> There is huge change in this version, thank Igor, Stefan, Paolo, Eduardo,
> >> Michael for their valuable comments, the patchset finally gets better 
> >> shape.
> >> - changes from Igor's comments:
> >>    1) abstract dimm device type from pc-dimm and create nvdimm device 
> >> based on
> >>       dimm, then it uses memory backend device as nvdimm's memory and NUMA 
> >> has
> >>       easily been implemented.
> >>    2) let file-backend device support any kind of filesystem not only for
> >>       hugetlbfs and let it work on file not only for directory which is
> >>       achieved by extending 'mem-path' - if it's a directory then it works 
> >> as
> >>       current behavior, otherwise if it's file then directly allocates 
> >> memory
> >>       from it.
> >>    3) we figure out a unused memory hole below 4G that is 0xFF00000 ~
> >>       0xFFF00000, this range is large enough for NVDIMM ACPI as build 
> >> 64-bit
> >>       ACPI SSDT/DSDT table will break windows XP.
> >>       BTW, only make SSDT.rev = 2 can not work since the width is only 
> >> depended
> >>       on DSDT.rev based on 19.6.28 DefinitionBlock (Declare Definition 
> >> Block)
> >>       in ACPI spec:
> >> | Note: For compatibility with ACPI versions before ACPI 2.0, the bit
> >> | width of Integer objects is dependent on the ComplianceRevision of the 
> >> DSDT.
> >> | If the ComplianceRevision is less than 2, all integers are restricted to 
> >> 32
> >> | bits. Otherwise, full 64-bit integers are used. The version of the DSDT 
> >> sets
> >> | the global integer width for all integers, including integers in SSDTs.
> >>    4) use the lowest ACPI spec version to document AML terms.
> >>    5) use "nvdimm" as nvdimm device name instead of "pc-nvdimm"
> >>
> >> - changes from Stefan's comments:
> >>    1) do not do endian adjustment in-place since _DSM memory is visible to 
> >> guest
> >>    2) use target platform's target page size instead of fixed PAGE_SIZE
> >>       definition
> >>    3) lots of code style improvement and typo fixes.
> >>    4) live migration fix
> >> - changes from Paolo's comments:
> >>    1) improve the name of memory region
> >>
> >> - other changes:
> >>    1) return exact buffer size for _DSM method instead of the page size.
> >>    2) introduce mutex in NVDIMM ACPI as the _DSM memory is shared by all 
> >> nvdimm
> >>       devices.
> >>    3) NUMA support
> >>    4) implement _FIT method
> >>    5) rename "configdata" to "reserve-label-data"
> >>    6) simplify _DSM arg3 determination
> >>    7) main changelog update to let it reflect v3.
> >>
> >> Changlog in v2:
> >> - Use litten endian for DSM method, thanks for Stefan's suggestion
> >>
> >> - introduce a new parameter, @configdata, if it's false, Qemu will
> >>    build a static and readonly namespace in memory and use it serveing
> >>    for DSM GET_CONFIG_SIZE/GET_CONFIG_DATA requests. In this case, no
> >>    reserved region is needed at the end of the @file, it is good for
> >>    the user who want to pass whole nvdimm device and make its data
> >>    completely be visible to guest
> >>
> >> - divide the source code into separated files and add maintain info
> >>
> >> BTW, PCOMMIT virtualization on KVM side is work in progress, hopefully will
> >> be posted on next week
> >>
> >> ====== Background ======
> >> NVDIMM (A Non-Volatile Dual In-line Memory Module) is going to be supported
> >> on Intel's platform. They are discovered via ACPI and configured by _DSM
> >> method of NVDIMM device in ACPI. There has some supporting documents which
> >> can be found at:
> >> ACPI 6: http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf
> >> NVDIMM Namespace: http://pmem.io/documents/NVDIMM_Namespace_Spec.pdf
> >> DSM Interface Example: 
> >> http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf
> >> Driver Writer's Guide: 
> >> http://pmem.io/documents/NVDIMM_Driver_Writers_Guide.pdf
> >>
> >> Currently, the NVDIMM driver has been merged into upstream Linux Kernel and
> >> this patchset tries to enable it in virtualization field
> >>
> >> ====== Design ======
> >> NVDIMM supports two mode accesses, one is PMEM which maps NVDIMM into CPU's
> >> address space then CPU can directly access it as normal memory, another is
> >> BLK which is used as block device to reduce the occupying of CPU address
> >> space
> >>
> >> BLK mode accesses NVDIMM via Command Register window and Data Register 
> >> window.
> >> BLK virtualization has high workload since each sector access will cause at
> >> least two VM-EXIT. So we currently only imperilment vPMEM in this patchset
> >>
> >> --- vPMEM design ---
> >> We introduce a new device named "nvdimm", it uses memory backend device as
> >> NVDIMM memory. The file in file-backend device can be a regular file and 
> >> block
> >> device. We can use any file when we do test or emulation, however,
> >> in the real word, the files passed to guest are:
> >> - the regular file in the filesystem with DAX enabled created on NVDIMM 
> >> device
> >>    on host
> >> - the raw PMEM device on host, e,g /dev/pmem0
> >> Memory access on the address created by mmap on these kinds of files can
> >> directly reach NVDIMM device on host.
> >>
> >> --- vConfigure data area design ---
> >> Each NVDIMM device has a configure data area which is used to store label
> >> namespace data. In order to emulating this area, we divide the file into 
> >> two
> >> parts:
> >> - first parts is (0, size - 128K], which is used as PMEM
> >> - 128K at the end of the file, which is used as Label Data Area
> >> So that the label namespace data can be persistent during power lose or 
> >> system
> >> failure.
> >>
> >> We also support passing the whole file to guest without reserve any region 
> >> for
> >> label data area which is achieved by "reserve-label-data" parameter - if 
> >> it's
> >> false then QEMU will build static and readonly namespace in memory and that
> >> namespace contains the whole file size. The parameter is false on default.
> >>
> >> --- _DSM method design ---
> >> _DSM in ACPI is used to configure NVDIMM, currently we only allow access of
> >> label namespace data, i.e, Get Namespace Label Size (Function Index 4),
> >> Get Namespace Label Data (Function Index 5) and Set Namespace Label Data
> >> (Function Index 6)
> >>
> >> _DSM uses two pages to transfer data between ACPI and Qemu, the first page
> >> is RAM-based used to save the input info of _DSM method and Qemu reuse it
> >> store output info and another page is MMIO-based, ACPI write data to this
> >> page to transfer the control to Qemu
> >>
> >> ====== Test ======
> >> In host
> >> 1) create memory backed file, e.g # dd if=zero of=/tmp/nvdimm bs=1G 
> >> count=10
> >> 2) append "-object memory-backend-file,share,id=mem1,
> >>     mem-path=/tmp/nvdimm -device nvdimm,memdev=mem1,reserve-label-data,
> >>     id=nv1" in QEMU command line
> >>
> >> In guest, download the latest upsteam kernel (4.2 merge window) and enable
> >> ACPI_NFIT, LIBNVDIMM and BLK_DEV_PMEM.
> >> 1) insmod drivers/nvdimm/libnvdimm.ko
> >> 2) insmod drivers/acpi/nfit.ko
> >> 3) insmod drivers/nvdimm/nd_btt.ko
> >> 4) insmod drivers/nvdimm/nd_pmem.ko
> >> You can see the whole nvdimm device used as a single namespace and 
> >> /dev/pmem0
> >> appears. You can do whatever on /dev/pmem0 including DAX access.
> >>
> >> Currently Linux NVDIMM driver does not support namespace operation on this
> >> kind of PMEM, apply below changes to support dynamical namespace:
> >>
> >> @@ -798,7 +823,8 @@ static int acpi_nfit_register_dimms(struct 
> >> acpi_nfit_desc *a
> >>                          continue;
> >>                  }
> >>
> >> -               if (nfit_mem->bdw && nfit_mem->memdev_pmem)
> >> +               //if (nfit_mem->bdw && nfit_mem->memdev_pmem)
> >> +               if (nfit_mem->memdev_pmem)
> >>                          flags |= NDD_ALIASING;
> >>
> >> You can append another NVDIMM device in guest and do:
> >> # cd /sys/bus/nd/devices/
> >> # cd namespace1.0/
> >> # echo `uuidgen` > uuid
> >> # echo `expr 1024 \* 1024 \* 128` > size
> >> then reload nd.pmem.ko
> >>
> >> You can see /dev/pmem1 appears
> >>
> >> ====== TODO ======
> >> NVDIMM hotplug support
> >>
> >> Xiao Guangrong (32):
> >>    acpi: add aml_derefof
> >>    acpi: add aml_sizeof
> >>    acpi: add aml_create_field
> >>    acpi: add aml_mutex, aml_acquire, aml_release
> >>    acpi: add aml_concatenate
> >>    acpi: add aml_object_type
> >>    util: introduce qemu_file_get_page_size()
> >>    exec: allow memory to be allocated from any kind of path
> >>    exec: allow file_ram_alloc to work on file
> >>    hostmem-file: clean up memory allocation
> >>    hostmem-file: use whole file size if possible
> >>    pc-dimm: remove DEFAULT_PC_DIMMSIZE
> >>    pc-dimm: make pc_existing_dimms_capacity static and rename it
> >>    pc-dimm: drop the prefix of pc-dimm
> >>    stubs: rename qmp_pc_dimm_device_list.c
> >>    pc-dimm: rename pc-dimm.c and pc-dimm.h
> >>    dimm: abstract dimm device from pc-dimm
> >>    dimm: get mapped memory region from DIMMDeviceClass->get_memory_region
> >>    dimm: keep the state of the whole backend memory
> >>    dimm: introduce realize callback
> >>    nvdimm: implement NVDIMM device abstract
> >>    nvdimm: init the address region used by NVDIMM ACPI
> >>    nvdimm: build ACPI NFIT table
> >>    nvdimm: init the address region used by DSM method
> >>    nvdimm: build ACPI nvdimm devices
> >>    nvdimm: save arg3 for NVDIMM device _DSM method
> >>    nvdimm: support DSM_CMD_IMPLEMENTED function
> >>    nvdimm: support DSM_CMD_NAMESPACE_LABEL_SIZE function
> >>    nvdimm: support DSM_CMD_GET_NAMESPACE_LABEL_DATA
> >>    nvdimm: support DSM_CMD_SET_NAMESPACE_LABEL_DATA
> >>    nvdimm: allow using whole backend memory as pmem
> >>    nvdimm: add maintain info
> >>
> >>   MAINTAINERS                                        |   6 +
> >>   backends/hostmem-file.c                            |  58 +-
> >>   default-configs/i386-softmmu.mak                   |   2 +
> >>   default-configs/x86_64-softmmu.mak                 |   2 +
> >>   exec.c                                             | 113 ++-
> >>   hmp.c                                              |   2 +-
> >>   hw/Makefile.objs                                   |   2 +-
> >>   hw/acpi/aml-build.c                                |  83 ++
> >>   hw/acpi/ich9.c                                     |   8 +-
> >>   hw/acpi/memory_hotplug.c                           |  26 +-
> >>   hw/acpi/piix4.c                                    |   8 +-
> >>   hw/i386/acpi-build.c                               |   4 +
> >>   hw/i386/pc.c                                       |  37 +-
> >>   hw/mem/Makefile.objs                               |   3 +
> >>   hw/mem/{pc-dimm.c => dimm.c}                       | 240 ++---
> >>   hw/mem/nvdimm/acpi.c                               | 961 
> >> +++++++++++++++++++++
> >>   hw/mem/nvdimm/internal.h                           |  41 +
> >>   hw/mem/nvdimm/namespace.c                          | 309 +++++++
> >>   hw/mem/nvdimm/nvdimm.c                             | 136 +++
> >>   hw/mem/pc-dimm.c                                   | 506 +----------
> >>   hw/ppc/spapr.c                                     |  20 +-
> >>   include/hw/acpi/aml-build.h                        |   8 +
> >>   include/hw/i386/pc.h                               |   4 +-
> >>   include/hw/mem/{pc-dimm.h => dimm.h}               |  68 +-
> >>   include/hw/mem/nvdimm.h                            |  58 ++
> >>   include/hw/mem/pc-dimm.h                           | 105 +--
> >>   include/hw/ppc/spapr.h                             |   2 +-
> >>   include/qemu/osdep.h                               |   1 +
> >>   numa.c                                             |   4 +-
> >>   qapi-schema.json                                   |   8 +-
> >>   qmp.c                                              |   4 +-
> >>   stubs/Makefile.objs                                |   2 +-
> >>   ...c_dimm_device_list.c => qmp_dimm_device_list.c} |   4 +-
> >>   target-ppc/kvm.c                                   |  21 +-
> >>   trace-events                                       |   8 +-
> >>   util/oslib-posix.c                                 |  16 +
> >>   util/oslib-win32.c                                 |   5 +
> >>   37 files changed, 2023 insertions(+), 862 deletions(-)
> >>   rename hw/mem/{pc-dimm.c => dimm.c} (65%)
> >>   create mode 100644 hw/mem/nvdimm/acpi.c
> >>   create mode 100644 hw/mem/nvdimm/internal.h
> >>   create mode 100644 hw/mem/nvdimm/namespace.c
> >>   create mode 100644 hw/mem/nvdimm/nvdimm.c
> >>   rewrite hw/mem/pc-dimm.c (91%)
> >>   rename include/hw/mem/{pc-dimm.h => dimm.h} (50%)
> >>   create mode 100644 include/hw/mem/nvdimm.h
> >>   rewrite include/hw/mem/pc-dimm.h (97%)
> >>   rename stubs/{qmp_pc_dimm_device_list.c => qmp_dimm_device_list.c} (56%)
> >>
> >> --
> >> 1.8.3.1
> >>
> >> --
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> >> the body of a message to address@hidden
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
> >
> >