fix #27138800

commit 8c2e408e73f735d2e6e8b43f9b038c9abb082939 upstream.

This patch fixes below sparse warning related to __virtio
type in virtio pmem driver. This is reported by Intel test
bot on linux-next tree.

nd_virtio.c:56:28: warning: incorrect type in assignment
                                (different base types)
nd_virtio.c:56:28:    expected unsigned int [unsigned] [usertype] type
nd_virtio.c:56:28:    got restricted __virtio32
nd_virtio.c:93:59: warning: incorrect type in argument 2
                                (different base types)
nd_virtio.c:93:59:    expected restricted __virtio32 [usertype] val
nd_virtio.c:93:59:    got unsigned int [unsigned] [usertype] ret
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NPankaj Gupta <pagupta@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NYang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: NXunlei Pang <xlpang@linux.alibaba.com>

fix #27138800

commit 6e84200c0a2994b991259d19450eee561029bf70 upstream.

This patch adds virtio-pmem driver for KVM guest.

Guest reads the persistent memory range information from
Qemu over VIRTIO and registers it on nvdimm_bus. It also
creates a nd_region object with the persistent memory
range information so that existing 'nvdimm/pmem' driver
can reserve this into system memory map. This way
'virtio-pmem' driver uses existing functionality of pmem
driver to register persistent memory compatible for DAX
capable filesystems.

This also provides function to perform guest flush over
VIRTIO from 'pmem' driver when userspace performs flush
on DAX memory range.
Signed-off-by: NPankaj Gupta <pagupta@redhat.com>
Reviewed-by: NYuval Shaia <yuval.shaia@oracle.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJakub Staron <jstaron@google.com>
Tested-by: NJakub Staron <jstaron@google.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NYang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: NXunlei Pang <xlpang@linux.alibaba.com>