On Tue, Jul 02, 2019 at 06:07:44AM -0400, Pankaj Gupta wrote:
>
>>
>> On Wed, Jun 19, 2019 at 03:19:00PM +0530, Pankaj Gupta wrote:
>> > This patch series has implementation for "virtio pmem"
>> > device. "virtio pmem" is persistent memory(nvdimm) device in
>> > guest which allows to bypass the guest page cache. This
>> > also implements a VIRTIO based asynchronous flush mechanism.
>> > Details of project idea for 'virtio pmem' flushing interface
>> > is shared [2] & [3].
>> >
>> > Sharing Qemu device emulation in this patchset. Tested with
>> > guest kernel driver [1]. This series is based on David's
>> > memory device refactoring [5] work with modified version of
>> > my initial virtio pmem [4] series.
>> >
>> > Usage:
>> > ./qemu -name test -machine pc -m 8G,slots=240,maxmem=20G
>> > -object memory-backend-file,id=mem1,share,mem-path=test.img,
>> > size=4G,share
>> > -device virtio-pmem-pci,memdev=mem1,id=nv1
>> >
>>
>> Hi, Pankaj
>
>Hi Wei,
>
>>
>> I tried this series with v14 kernel driver, while getting some error on using
>> this. Not sure this is my error configuration.
>>
>> The qemu command line is:
>>
>> -object
>>
>> memory-backend-file,id=mem1,share=on,mem-path=/dev/dax0.0,size=1G,align=2M
>> -device virtio-pmem-pci,memdev=mem1,id=nv1
>
>Are you using host backing on real NVDIMM? Currently, we only support backing
>image
>file on regular SSD. We have plans to support backing file on real NVDIMM
>device
>as well but this is part of future work.
>
>Can you please try by allocating a raw image file on regular SSD. It is
>working fine
>for me.
>
I created a file with 2G on my disk.
#ll -h 2G-file
-rw-r--r-- 1 richard richard 2.0G 6月 26 09:26 2G-file
The command line is changed to:
-object
memory-backend-file,id=mem1,share,mem-path=/home/richard/guest/2G-file,size=2G
-device virtio-pmem-pci,memdev=mem1,id=nv1
The behavior in guest is the same.
I took a look into the directory /sys/bus/nd/device. These files are listed.
Compared with normal system, one device file is missed.
btt0.0 dax0.0 namespace0.0 ndbus0 pfn0.0 region0
But the sysfs shows pmem0 block device is created.
/sys/devices/pci0000:00/0000:00:04.0/virtio0/ndbus0/region0/namespace0.0/block/pmem0
Then I took a look into the pci device:
# lspci -vs 00:04.0
00:04.0 Unclassified device [00ff]: Red Hat, Inc. Device 1013
Subsystem: Red Hat, Inc. Device 001b
Physical Slot: 4
Flags: bus master, fast devsel, latency 0, IRQ 11
I/O ports at c040 [size=64]
Memory at fe000000 (64-bit, prefetchable) [size=16K]
Capabilities: [84] Vendor Specific Information: VirtIO: <unknown>
Capabilities: [70] Vendor Specific Information: VirtIO: Notify
Capabilities: [60] Vendor Specific Information: VirtIO: DeviceCfg
Capabilities: [50] Vendor Specific Information: VirtIO: ISR
Capabilities: [40] Vendor Specific Information: VirtIO: CommonCfg
Kernel driver in use: virtio-pci
This looks good.
>>
>> The guest boots up and I can see /dev/pmem0 device. But when I want to
>> partition this device, I got the error:
>>
>> # parted /dev/pmem0 mklabel gpt
>> Warning: Error fsyncing/closing /dev/pmem0: Input/output error
>>
>> Also I see an error when running "ndctl list":
>>
>> libndctl: __sysfs_device_parse: ndctl0: add_dev() failed
>
>Will look at this if it is related.
This log still there.
>
>Thanks,
>Pankaj
>>
>> Would you mind letting me know which part I am wrong?
>>
>> > (qemu) info memory-devices
>> > Memory device [virtio-pmem]: "nv1"
>> > memaddr: 0x240000000
>> > size: 4294967296
>> > memdev: /objects/mem1
>> >
>> > Implementation is divided into two parts:
>> > New virtio pmem guest driver and qemu code changes for new
>> > virtio pmem paravirtualized device. In this series we are
>> > sharing Qemu device emulation.
>> >
>> >1. Guest virtio-pmem kernel driver
>> >---------------------------------
>> > - Reads persistent memory range from paravirt device and
>> > registers with 'nvdimm_bus'.
>> > - 'nvdimm/pmem' driver uses this information to allocate
>> > persistent memory region and setup filesystem operations
>> > to the allocated memory.
>> > - virtio pmem driver implements asynchronous flushing
>> > interface to flush from guest to host.
>> >
>> >2. Qemu virtio-pmem device
>> >---------------------------------
>> > - Creates virtio pmem device and exposes a memory range to
>> > KVM guest.
>> > - At host side this is file backed memory which acts as
>> > persistent memory.
>> > - Qemu side flush uses aio thread pool API's and virtio
>> > for asynchronous guest multi request handling.
>> >
>> > Virtio-pmem security implications and suggested countermeasures:
>> > ---------------------------------------------------------------
>> >
>> > In previous posting of kernel driver, there was discussion [7]
>> > on possible implications of page cache side channel attacks with
>> > virtio pmem. After thorough analysis of details of known side
>> > channel attacks, below are the suggestions:
>> >
>> > - Depends entirely on how host backing image file is mapped
>> > into guest address space.
>> >
>> > - virtio-pmem device emulation, by default shared mapping is used
>> > to map host backing file. It is recommended to use separate
>> > backing file at host side for every guest. This will prevent
>> > any possibility of executing common code from multiple guests
>> > and any chance of inferring guest local data based based on
>> > execution time.
>> >
>> > - If backing file is required to be shared among multiple guests
>> > it is recommended to don't support host page cache eviction
>> > commands from the guest driver. This will avoid any possibility
>> > of inferring guest local data or host data from another guest.
>> >
>> > - Proposed device specification [6] for virtio-pmem device with
>> > details of possible security implications and suggested
>> > countermeasures for device emulation.
>> >
>> >Changes from PATCH v1:
>> > - Change proposed version from qemu 4.0 to 4.1 - Eric
>> > - Remove virtio queue_add from unrealize function - Cornelia
>> >
>> >[1] https://lkml.org/lkml/2019/6/12/624
>> >[2] https://www.spinics.net/lists/kvm/msg149761.html
>> >[3] https://www.spinics.net/lists/kvm/msg153095.html
>> >[4] https://marc.info/?l=linux-kernel&m=153572228719237&w=2
>> >[5] https://marc.info/?l=qemu-devel&m=153555721901824&w=2
>> >[6] https://lists.oasis-open.org/archives/virtio-dev/201903/msg00083.html
>> >[7] https://lkml.org/lkml/2019/1/9/1191
>> >
>> > Pankaj Gupta (3):
>> > virtio-pmem: add virtio device
>> > virtio-pmem: sync linux headers
>> > virtio-pci: proxy for virtio-pmem
>> >
>> > David Hildenbrand (4):
>> > virtio-pci: Allow to specify additional interfaces for the base type
>> > hmp: Handle virtio-pmem when printing memory device infos
>> > numa: Handle virtio-pmem in NUMA stats
>> > pc: Support for virtio-pmem-pci
>> >
>> > hmp.c | 27 ++-
>> > hw/i386/Kconfig | 1
>> > hw/i386/pc.c | 72 ++++++++++
>> > hw/virtio/Kconfig | 10 +
>> > hw/virtio/Makefile.objs | 2
>> > hw/virtio/virtio-pci.c | 1
>> > hw/virtio/virtio-pci.h | 1
>> > hw/virtio/virtio-pmem-pci.c | 131 ++++++++++++++++++
>> > hw/virtio/virtio-pmem-pci.h | 34 ++++
>> > hw/virtio/virtio-pmem.c | 189
>> > +++++++++++++++++++++++++++
>> > include/hw/pci/pci.h | 1
>> > include/hw/virtio/virtio-pmem.h | 49 +++++++
>> > include/standard-headers/linux/virtio_ids.h | 1
>> > include/standard-headers/linux/virtio_pmem.h | 35 +++++
>> > numa.c | 24 +--
>> > qapi/misc.json | 28 +++-
>> > 16 files changed, 580 insertions(+), 26 deletions(-)
>> >----
>>
>> --
>> Wei Yang
>> Help you, Help me
>>
>>
--
Wei Yang
Help you, Help me
