diff options
Diffstat (limited to 'docs/specs')
| -rw-r--r-- | docs/specs/acpi_nvdimm.txt | 58 |
1 files changed, 55 insertions, 3 deletions
diff --git a/docs/specs/acpi_nvdimm.txt b/docs/specs/acpi_nvdimm.txt index 0fdd251fc0..4aa5e3de29 100644 --- a/docs/specs/acpi_nvdimm.txt +++ b/docs/specs/acpi_nvdimm.txt @@ -127,6 +127,58 @@ _DSM process diagram: | result from the page | | | +--------------------------+ +--------------+ - _FIT implementation - ------------------- - TODO (will fill it when nvdimm hotplug is introduced) +Device Handle Reservation +------------------------- +As we mentioned above, byte 0 ~ byte 3 in the DSM memory save NVDIMM device +handle. The handle is completely QEMU internal thing, the values in range +[0, 0xFFFF] indicate nvdimm device (O means nvdimm root device named NVDR), +other values are reserved by other purpose. + +Current reserved handle: +0x10000 is reserved for QEMU internal DSM function called on the root +device. + +QEMU internal use only _DSM function +------------------------------------ +UUID, 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62, is reserved for QEMU internal +DSM function. + +There is the function introduced by QEMU and only used by QEMU internal. + +1) Read FIT + As we only reserved one page for NVDIMM ACPI it is impossible to map the + whole FIT data to guest's address space. This function is used by _FIT + method to read a piece of FIT data from QEMU. + + Input parameters: + Arg0 – UUID {set to 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62} + Arg1 – Revision ID (set to 1) + Arg2 - Function Index, 0x1 + Arg3 - A package containing a buffer whose layout is as follows: + + +----------+-------------+-------------+-----------------------------------+ + | Filed | Byte Length | Byte Offset | Description | + +----------+-------------+-------------+-----------------------------------+ + | offset | 4 | 0 | the offset of FIT buffer | + +----------+-------------+-------------+-----------------------------------+ + + Output: + +----------+-------------+-------------+-----------------------------------+ + | Filed | Byte Length | Byte Offset | Description | + +----------+-------------+-------------+-----------------------------------+ + | | | | return status codes | + | | | | 0x100 indicates fit has been | + | status | 4 | 0 | updated | + | | | | other follows Chapter 3 in DSM | + | | | | Spec Rev1 | + +----------+-------------+-------------+-----------------------------------+ + | fit data | Varies | 4 | FIT data | + | | | | | + +----------+-------------+-------------+-----------------------------------+ + + The FIT offset is maintained by the caller itself, current offset plugs + the length returned by the function is the next offset we should read. + When all the FIT data has been read out, zero length is returned. + + If it returns 0x100, OSPM should restart to read FIT (read from offset 0 + again). |