On Mon, 7 Nov 2016 19:13:41 +0800
Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> wrote:
> Improve the description and clearly document the length field
>
> Suggested-by: Igor Mammedov <imammedo@xxxxxxxxxx>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
Reviewed-by: Igor Mammedov <imammedo@xxxxxxxxxx>
> ---
> docs/specs/acpi_nvdimm.txt | 96 +++++++++++++++++++++++-----------------------
> 1 file changed, 47 insertions(+), 49 deletions(-)
>
> diff --git a/docs/specs/acpi_nvdimm.txt b/docs/specs/acpi_nvdimm.txt
> index d244147..3f322e6 100644
> --- a/docs/specs/acpi_nvdimm.txt
> +++ b/docs/specs/acpi_nvdimm.txt
> @@ -65,8 +65,8 @@ _FIT(Firmware Interface Table)
> The detailed definition of the structure can be found at ACPI 6.0: 5.2.25
> NVDIMM Firmware Interface Table (NFIT).
>
> -QEMU NVDIMM Implemention
> -========================
> +QEMU NVDIMM Implementation
> +==========================
> QEMU uses 4 bytes IO Port starting from 0x0a18 and a RAM-based memory page
> for NVDIMM ACPI.
>
> @@ -80,8 +80,17 @@ Memory:
> emulates _DSM access and writes the output data to it.
>
> ACPI writes _DSM Input Data (based on the offset in the page):
> - [0x0 - 0x3]: 4 bytes, NVDIMM Device Handle, 0 is reserved for NVDIMM
> - Root device.
> + [0x0 - 0x3]: 4 bytes, NVDIMM Device Handle.
> +
> + The handle is completely QEMU internal thing, the values in
> + range [1, 0xFFFF] indicate nvdimm device. Other values are
> + reserved for other purposes.
> +
> + Reserved handles:
> + 0 is reserved for nvdimm root device named NVDR.
> + 0x10000 is reserved for QEMU internal DSM function called on
> + the root device.
> +
> [0x4 - 0x7]: 4 bytes, Revision ID, that is the Arg1 of _DSM method.
> [0x8 - 0xB]: 4 bytes. Function Index, that is the Arg2 of _DSM method.
> [0xC - 0xFFF]: 4084 bytes, the Arg3 of _DSM method.
> @@ -132,28 +141,12 @@ NVDIMM hotplug
> ACPI BIOS GPE.4 handler is dedicated for notifying OS about nvdimm device
> hot-add event.
>
> -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.
> + _FIT method uses _DSM method to fetch NFIT structures blob from QEMU
> + in 1 page sized increments which are then concatenated and returned
> + as _FIT method result.
>
> Input parameters:
> Arg0 – UUID {set to 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62}
> @@ -161,29 +154,34 @@ There is the function introduced by QEMU and only used by QEMU internal.
> 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).
> + +----------+--------+--------+-------------------------------------------+
> + | Field | Length | Offset | Description |
> + +----------+--------+--------+-------------------------------------------+
> + | offset | 4 | 0 | offset in QEMU's NFIT structures blob to |
> + | | | | read from |
> + +----------+--------+--------+-------------------------------------------+
> +
> + Output layout in the dsm memory page:
> + +----------+--------+--------+-------------------------------------------+
> + | Field | Length | Offset | Description |
> + +----------+--------+--------+-------------------------------------------+
> + | length | 4 | 0 | length of entire returned data |
> + | | | | (including this header) |
> + +----------+-----------------+-------------------------------------------+
> + | | | | return status codes |
> + | | | | 0x0 - success |
> + | | | | 0x100 - error caused by NFIT update while |
> + | status | 4 | 4 | read by _FIT wasn't completed, other |
> + | | | | codes follow Chapter 3 in DSM Spec Rev1 |
> + +----------+-----------------+-------------------------------------------+
> + | fit data | Varies | 8 | contains FIT data, this field is present |
> + | | | | if status field is 0; |
> + +----------+--------+--------+-------------------------------------------+
> +
> + The FIT offset is maintained by the OSPM itself, current offset plus
> + the size of the fit data returned by the function is the next offset
> + OSPM should read. When all FIT data has been read out, zero fit data
> + size is returned.
> +
> + If it returns status code 0x100, OSPM should restart to read FIT (read
> + from offset 0 again).
--
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