I spent way too much time trying to figure out why the emulated NVDIMM
was missing under Linux. In an effort to help others who might be looking
for these kinds of things in the future, include a hint.
Signed-off-by: NKees Cook <keescook@chromium.org>
Message-id: 20181018201351.GA25286@beast
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

When QEMU emulates vNVDIMM labels and migrates vNVDIMM devices, it
needs to know whether the backend storage is a real persistent memory,
in order to decide whether special operations should be performed to
ensure the data persistence.

This boolean option 'pmem' allows users to specify whether the backend
storage of memory-backend-file is a real persistent memory. If
'pmem=on', QEMU will set the flag RAM_PMEM in the RAM block of the
corresponding memory region. If 'pmem' is set while lack of libpmem
support, a error is generated.
Signed-off-by: NJunyan He <junyan.he@intel.com>
Signed-off-by: NHaozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NIgor Mammedov <imammedo@redhat.com>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Replace the "nvdimm-cap" option which took numeric arguments such as "2"
with a more user friendly "nvdimm-persistence" option which takes symbolic
arguments "cpu" or "mem-ctrl".
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: NMichael S. Tsirkin <mst@redhat.com>
Suggested-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add a machine command line option to allow the user to control the Platform
Capabilities Structure in the virtualized NFIT.  This Platform Capabilities
Structure was added in ACPI 6.2 Errata A.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Currently the only vNVDIMM backend can guarantee the guest write
persistence is device DAX on Linux, because no host-side kernel cache
is involved in the guest access to it. The approach to detect whether
the backend is device DAX needs to access sysfs, which may not work
with SELinux.

Instead, we add the 'unarmed' option to device 'nvdimm', so that users
or management utils, which have enough knowledge about the backend,
can control the unarmed flag in guest ACPI NFIT via this option. The
guest Linux NVDIMM driver, for example, will mark the corresponding
vNVDIMM device read-only if the unarmed flag in guest NFIT is set.

The default value of 'unarmed' option is 'off' in order to keep the
backwards compatibility.
Signed-off-by: NHaozhong Zhang <haozhong.zhang@intel.com>
Message-Id: <20171211072806.2812-4-haozhong.zhang@intel.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

When mmap(2) the backend files, QEMU uses the host page size
(getpagesize(2)) by default as the alignment of mapping address.
However, some backends may require alignments different than the page
size. For example, mmap a device DAX (e.g., /dev/dax0.0) on Linux
kernel 4.13 to an address, which is 4K-aligned but not 2M-aligned,
fails with a kernel message like

[617494.969768] dax dax0.0: qemu-system-x86: dax_mmap: fail, unaligned vma (0x7fa37c579000 - 0x7fa43c579000, 0x1fffff)

Because there is no common approach to get such alignment requirement,
we add the 'align' option to 'memory-backend-file', so that users or
management utils, which have enough knowledge about the backend, can
specify a proper alignment via this option.
Signed-off-by: NHaozhong Zhang <haozhong.zhang@intel.com>
Message-Id: <20171211072806.2812-2-haozhong.zhang@intel.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
[ehabkost: fixed typo, fixed error_setg() format string]
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

Signed-off-by: NHaozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: NXiao Guangrong <guangrong.xiao@linux.intel.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>