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

[Dan Williams]

On Sat, Oct 10, 2015 at 8:52 PM, Xiao Guangrong
<address@hidden> wrote:
[..]
> ====== 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;

This is just for testing purposes, right?  I expect guests can
sub-divide persistent memory capacity by partitioning the resulting
block device(s).