> > > >> > >> 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.
Are you still facing an error with this? or its working fine for you? > > I took a look into the directory /sys/bus/nd/device. These files are listed. > Compared with normal system, one device file is missed. virtio pmem does not support namespace/region mappings which ACPI NFIT supports. > > 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: > 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. Good to know. > > >> > >> 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. It looks to me libndctl needs to be taught about about virtio pmem data parsing. But this is unrelated to kernel and qemu patch series. > > > > >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 > >
