diff options
| author | Ross Zwisler <ross.zwisler@linux.intel.com> | 2018-05-21 10:32:02 -0600 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2018-06-01 19:20:38 +0300 |
| commit | 9ab3aad2813ce5d9e79c86cb65a013016b61a08f (patch) | |
| tree | df11a77f3b4a5337fe868fbfa9b715cf00e4e56d /docs | |
| parent | 2e0c56cdde0b4bbd6ed4070626ed72d1977da07f (diff) | |
nvdimm, acpi: support NFIT platform capabilities
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: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/nvdimm.txt | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt index e903d8bb09..8b48fb4633 100644 --- a/docs/nvdimm.txt +++ b/docs/nvdimm.txt @@ -153,3 +153,30 @@ guest NVDIMM region mapping structure. This unarmed flag indicates guest software that this vNVDIMM device contains a region that cannot accept persistent writes. In result, for example, the guest Linux NVDIMM driver, marks such vNVDIMM device as read-only. + +Platform Capabilities +--------------------- + +ACPI 6.2 Errata A added support for a new Platform Capabilities Structure +which allows the platform to communicate what features it supports related to +NVDIMM data durability. Users can provide a capabilities value to a guest via +the optional "nvdimm-cap" machine command line option: + + -machine pc,accel=kvm,nvdimm,nvdimm-cap=2 + +This "nvdimm-cap" field is an integer, and is the combined value of the +various capability bits defined in table 5-137 of the ACPI 6.2 Errata A spec. + +Here is a quick summary of the three bits that are defined as of that spec: + +Bit[0] - CPU Cache Flush to NVDIMM Durability on Power Loss Capable. +Bit[1] - Memory Controller Flush to NVDIMM Durability on Power Loss Capable. + Note: If bit 0 is set to 1 then this bit shall be set to 1 as well. +Bit[2] - Byte Addressable Persistent Memory Hardware Mirroring Capable. + +So, a "nvdimm-cap" value of 2 would mean that the platform supports Memory +Controller Flush on Power Loss, a value of 3 would mean that the platform +supports CPU Cache Flush and Memory Controller Flush on Power Loss, etc. + +For a complete list of the flags available and for more detailed descriptions, +please consult the ACPI spec. |