On Tue, Jul 02, 2019 at 09:31:43PM -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. > >Are you still facing an error with this? or its working fine for you? >
I can partition and mkfs with /dev/pmem0 after I use the SSD backend. >> >> 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. > Ok, thanks. >> >> 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. > Ok, if it works, we could list those regions? and change pmem0 mode to dax mode, right? >> >> > >> >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 >> >> -- Wei Yang Help you, Help me