On 3/31/21 3:50 PM, Michael Ellerman wrote:
"Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> writes:
Shivaprasad G Bhat <sbhat@xxxxxxxxxxxxx> writes:
Add support for ND_REGION_ASYNC capability if the device tree
indicates 'ibm,hcall-flush-required' property in the NVDIMM node.
Flush is done by issuing H_SCM_FLUSH hcall to the hypervisor.
If the flush request failed, the hypervisor is expected to
to reflect the problem in the subsequent nvdimm H_SCM_HEALTH call.
This patch prevents mmap of namespaces with MAP_SYNC flag if the
nvdimm requires an explicit flush[1].
References:
[1] https://github.com/avocado-framework-tests/avocado-misc-tests/blob/master/memory/ndctl.py.data/map_sync.c
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Do we need an ack from nvdimm folks on this?
Or is it entirely powerpc internal (seems like it from the diffstat)?
This is within powerpc and we are implementing details w.r.t PAPR spec.
There is a Qemu implementation that is getting reviewed here
https://lore.kernel.org/linux-nvdimm/161650723087.2959.8703728357980727008.stgit@6532096d84d3
But with respect to this patch, we can take that independent of the Qemu
backend implementation.
-aneesh
