On Sun, Oct 11, 2015 at 9:33 PM, Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> wrote: > > > On 10/11/2015 05:17 AM, Dan Williams wrote: >> >> On Sat, Oct 10, 2015 at 8:52 PM, Xiao Guangrong >> <guangrong.xiao@xxxxxxxxxxxxxxx> 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 > > > It's used to validate NVDIMM _DSM method and static namespace following > NVDIMM specs... Static namespaces can be emitted without a label. Linux needs this to support existing "label-less" bare metal NVDIMMs. >> sub-divide persistent memory capacity by partitioning the resulting >> block device(s). > > > I understand that it's a Linux design... Hmm, can the same expectation > apply to PBLK? BLK-mode is a bit different as those namespaces have both configurable sector-size and an optional BTT. It is possible to expect multiple BLK namespaces per a given region with different settings. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
