On Fri, 12 Aug 2016 14:54:05 +0800
Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> wrote:
> _FIT is required for hotplug support, guest will inquire the updated
> device info from it if a hotplug event is received
>
> As FIT buffer is not completely mapped into guest address space, so a
> new function, Read FIT whose function index is 0xFFFFFFFF, is reserved
> by QEMU to read the piece of FIT buffer. The buffer is concatenated
> before _FIT return
Only issuer of UUID 2F10E7A4-9E91-11E4-89D3-123B93F75CBA can reserve
0xFFFFFFFF for some purposes.
So spec should be amended first or custom generated UUID should be used.
>
> Refer to docs/specs/acpi-nvdimm.txt for detailed design
and amend docs to reflect that.
>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> ---
> hw/acpi/nvdimm.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 82 insertions(+)
>
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index 0e2b9f0..4bbd1e7 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -886,6 +886,87 @@ static void nvdimm_build_device_dsm(Aml *dev, uint32_t handle)
> aml_append(dev, method);
> }
>
> +static void nvdimm_build_fit(Aml *dev)
> +{
> + Aml *method, *pkg, *buf, *buf_size, *offset, *call_result;
> + Aml *whilectx, *ifcond, *ifctx, *fit;
> +
> + buf = aml_local(0);
> + buf_size = aml_local(1);
> + fit = aml_local(2);
> +
> + /* build helper function, RFIT. */
> + method = aml_method("RFIT", 1, AML_NOTSERIALIZED);
since you create named fields (global variable) in method scope,
you should make method serialized. Same goes for _FIT method.
> + aml_append(method, aml_create_dword_field(aml_buffer(4, NULL),
> + aml_int(0), "OFST"));
> +
> + /* prepare input package. */
> + pkg = aml_package(1);
> + aml_append(method, aml_store(aml_arg(0), aml_name("OFST")));
> + aml_append(pkg, aml_name("OFST"));
> +
> + /* call Read_FIT function. */
> + call_result = aml_call5(NVDIMM_COMMON_DSM,
> + aml_touuid("2F10E7A4-9E91-11E4-89D3-123B93F75CBA"
> + /* UUID for NVDIMM Root Device */),
> + aml_int(1) /* Revision 1 */,
> + aml_int(0xFFFFFFFF) /* Read FIT. */,
> + pkg, aml_int(0) /* for root device. */);
> + aml_append(method, aml_store(call_result, buf));
> +
> + /* handle _DSM result. */
> + aml_append(method, aml_create_dword_field(buf,
> + aml_int(0) /* offset at byte 0 */, "STAU"));
> +
> + /* if something is wrong during _DSM. */
> + ifcond = aml_equal(aml_int(0 /* Success */), aml_name("STAU"));
> + ifctx = aml_if(aml_lnot(ifcond));
> + aml_append(ifctx, aml_return(aml_buffer(0, NULL)));
> + aml_append(method, ifctx);
> + aml_append(method, aml_store(aml_sizeof(buf), buf_size));
> + aml_append(method, aml_subtract(buf_size,
> + aml_int(4) /* the size of "STAU" */,
> + buf_size));
Since you handle error case the same as EOF case you could replace
it with EOF case here and on qemu side of interface as well. That should
simplify code a bit as you won't need to strip out func_ret_status.
> +
> + /* if we read the end of fit. */
> + ifctx = aml_if(aml_equal(buf_size, aml_int(0)));
> + aml_append(ifctx, aml_return(aml_buffer(0, NULL)));
> + aml_append(method, ifctx);
> +
> + aml_append(method, aml_store(aml_shiftleft(buf_size, aml_int(3)),
> + buf_size));
> + aml_append(method, aml_create_field(buf,
> + aml_int(4 * BITS_PER_BYTE), /* offset at byte 4.*/
> + buf_size, "BUFF"));
> + aml_append(method, aml_return(aml_name("BUFF")));
> + aml_append(dev, method);
> +
> + /* build _FIT. */
> + method = aml_method("_FIT", 0, AML_NOTSERIALIZED);
> + offset = aml_local(3);
> +
> + aml_append(method, aml_store(aml_buffer(0, NULL), fit));
> + aml_append(method, aml_store(aml_int(0), offset));
> +
> + whilectx = aml_while(aml_int(1));
> + aml_append(whilectx, aml_store(aml_call1("RFIT", offset), buf));
> + aml_append(whilectx, aml_store(aml_sizeof(buf), buf_size));
> +
> + /* finish fit read if no data is read out. */
> + ifctx = aml_if(aml_equal(buf_size, aml_int(0)));
> + aml_append(ifctx, aml_return(fit));
> + aml_append(whilectx, ifctx);
> +
> + /* update the offset. */
> + aml_append(whilectx, aml_add(offset, buf_size, offset));
> + /* append the data we read out to the fit buffer. */
> + aml_append(whilectx, aml_concatenate(fit, buf, fit));
> + aml_append(method, whilectx);
> +
> + aml_append(dev, method);
> +}
> +
> static void nvdimm_build_nvdimm_devices(Aml *root_dev, uint32_t ram_slots)
> {
> uint32_t slot;
> @@ -1001,6 +1082,7 @@ static void nvdimm_build_ssdt(GArray *table_offsets, GArray *table_data,
>
> /* 0 is reserved for root device. */
> nvdimm_build_device_dsm(dev, 0);
> + nvdimm_build_fit(dev);
>
> nvdimm_build_nvdimm_devices(dev, ram_slots);
>
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