[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 4/4] hvmloader: add support to load extra ACPI tables from qemu
On 01/26/16 14:32, Konrad Rzeszutek Wilk wrote: > On Tue, Jan 26, 2016 at 09:34:13AM -0700, Jan Beulich wrote: > > >>> On 26.01.16 at 16:57, <haozhong.zhang@xxxxxxxxx> wrote: > > > On 01/26/16 08:37, Jan Beulich wrote: > > >> >>> On 26.01.16 at 15:44, <konrad.wilk@xxxxxxxxxx> wrote: > > >> >> Last year at Linux Plumbers Conference I attended a session dedicated > > >> >> to NVDIMM support. I asked the very same question and the INTEL guy > > >> >> there told me there is indeed something like a partition table meant > > >> >> to describe the layout of the memory areas and their contents. > > >> > > > >> > It is described in details at pmem.io, look at Documents, see > > >> > http://pmem.io/documents/NVDIMM_Namespace_Spec.pdf see Namespaces > > >> > section. > > >> > > >> Well, that's about how PMEM and PBLK ranges get marked, but not > > >> about how use of the space inside a PMEM range is coordinated. > > >> > > > > > > How a NVDIMM is partitioned into pmem and pblk is described by ACPI NFIT > > > table. > > > Namespace to pmem is something like partition table to disk. > > > > But I'm talking about sub-dividing the space inside an individual > > PMEM range. > > The namespaces are it. > Because only one persistent memory namespace is allowed for an individual pmem, namespace can not be used to sub-divide. > Once you have done them you can mount the PMEM range under say /dev/pmem0 > and then put a filesystem on it (ext4, xfs) - and enable DAX support. > The DAX just means that the FS will bypass the page cache and write directly > to the virtual address. > > then one can create giant 'dd' images on this filesystem and pass it > to QEMU to .. expose as NVDIMM to the guest. Because it is a file - the blocks > (or MFNs) for the contents of the file are most certainly discontingous. > Though the 'dd' image may occupy discontingous MFNs on host pmem, we can map them to contiguous guest PFNs. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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