On Thu, Oct 12, 2017 at 2:25 PM, Pankaj Gupta <pagu...@redhat.com> wrote: > >> > This patch adds virtio-pmem driver for KVM guest. >> > Guest reads the persistent memory range information >> > over virtio bus from Qemu and reserves the range >> > as persistent memory. Guest also allocates a block >> > device corresponding to the pmem range which later >> > can be accessed with DAX compatible file systems. >> > Idea is to use the virtio channel between guest and >> > host to perform the block device flush for guest pmem >> > DAX device. >> > >> > There is work to do including DAX file system support >> > and other advanced features. >> > >> > Signed-off-by: Pankaj Gupta <pagu...@redhat.com> >> > --- >> > drivers/virtio/Kconfig | 10 ++ >> > drivers/virtio/Makefile | 1 + >> > drivers/virtio/virtio_pmem.c | 322 >> > +++++++++++++++++++++++++++++++++++++++ >> > include/uapi/linux/virtio_pmem.h | 55 +++++++ >> > 4 files changed, 388 insertions(+) >> > create mode 100644 drivers/virtio/virtio_pmem.c >> > create mode 100644 include/uapi/linux/virtio_pmem.h >> > >> > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig >> > index cff773f15b7e..0192c4bda54b 100644 >> > --- a/drivers/virtio/Kconfig >> > +++ b/drivers/virtio/Kconfig >> > @@ -38,6 +38,16 @@ config VIRTIO_PCI_LEGACY >> > >> > If unsure, say Y. >> > >> > +config VIRTIO_PMEM >> > + tristate "Virtio pmem driver" >> > + depends on VIRTIO >> > + ---help--- >> > + This driver adds persistent memory range within a KVM guest. >> >> I think we need to call this something other than persistent memory to >> make it clear that this not memory where the persistence can be >> managed from userspace. The persistence point always requires a driver >> call, so this is something distinctly different than "persistent >> memory". For example, it's a bug if this memory range ends up backing >> a device-dax range in the guest where there is no such thing as a >> driver callback to perform the flushing. How does this solution >> protect against that scenario? > > yes, you are right we are not providing device_dax in this case so it should > be clear from name. Any suggestion for name?
So currently /proc/iomem in a guest with a pmem device attached to a namespace looks like this: c00000000-13bfffffff : Persistent Memory c00000000-13bfffffff : namespace2.0 Can we call it "Virtio Shared Memory" to make it clear it is a different beast than typical "Persistent Memory"? You can likely inject your own name into the resource tree the same way we do in the NFIT driver. See acpi_nfit_insert_resource(). _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm