Re: [Qemu-devel] [PATCH v7 27/35] nvdimm acpi: build ACPI nvdimm devices

[Xiao Guangrong <guangrong.xiao@linux.intel.com>]

On 11/04/2015 04:56 PM, Igor Mammedov wrote:
> On Tue, 3 Nov 2015 22:22:40 +0800
> Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote:
>
>>
>>
>> On 11/03/2015 09:13 PM, Igor Mammedov wrote:
>>> On Mon,  2 Nov 2015 17:13:29 +0800
>>> Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote:
>>>
>>>> NVDIMM devices is defined in ACPI 6.0 9.20 NVDIMM Devices
>>>>
>>>> There is a root device under \_SB and specified NVDIMM devices are under the
>>>> root device. Each NVDIMM device has _ADR which returns its handle used to
>>>> associate MEMDEV structure in NFIT
>>>>
>>>> We reserve handle 0 for root device. In this patch, we save handle, handle,
>>>> arg1 and arg2 to dsm memory. Arg3 is conditionally saved in later patch
>>>>
>>>> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
>>>> ---
>>>>    hw/acpi/nvdimm.c | 184 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>    1 file changed, 184 insertions(+)
>>>>
>>>> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
>>>> index dd84e5f..53ed675 100644
>>>> --- a/hw/acpi/nvdimm.c
>>>> +++ b/hw/acpi/nvdimm.c
>>>> @@ -368,6 +368,15 @@ static void nvdimm_build_nfit(GSList *device_list, GArray *table_offsets,
>>>>        g_array_free(structures, true);
>>>>    }
>>>>
>>>> +struct NvdimmDsmIn {
>>>> +    uint32_t handle;
>>>> +    uint32_t revision;
>>>> +    uint32_t function;
>>>> +   /* the remaining size in the page is used by arg3. */
>>>> +    uint8_t arg3[0];
>>>> +} QEMU_PACKED;
>>>> +typedef struct NvdimmDsmIn NvdimmDsmIn;
>>>> +
>>>>    static uint64_t
>>>>    nvdimm_dsm_read(void *opaque, hwaddr addr, unsigned size)
>>>>    {
>>>> @@ -377,6 +386,7 @@ nvdimm_dsm_read(void *opaque, hwaddr addr, unsigned size)
>>>>    static void
>>>>    nvdimm_dsm_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
>>>>    {
>>>> +    fprintf(stderr, "BUG: we never write DSM notification IO Port.\n");
>>> it doesn't seem like this hunk belongs here
>>
>> Er, we have changed the logic:
>> - others:
>>     1) the buffer length is directly got from IO read rather than got
>>        from dsm memory
>> [ This has documented in v5's changelog. ]
>>
>> So, the IO write is replaced by IO read, nvdimm_dsm_write() should not be
>> triggered.
>>
>>>
>>>>    }
>>>>
>>>>    static const MemoryRegionOps nvdimm_dsm_ops = {
>>>> @@ -402,6 +412,179 @@ void nvdimm_init_acpi_state(MemoryRegion *memory, MemoryRegion *io,
>>>>        memory_region_add_subregion(io, NVDIMM_ACPI_IO_BASE, &state->io_mr);
>>>>    }
>>>>
>>>> +#define BUILD_STA_METHOD(_dev_, _method_)                                  \
>>>> +    do {                                                                   \
>>>> +        _method_ = aml_method("_STA", 0);                                  \
>>>> +        aml_append(_method_, aml_return(aml_int(0x0f)));                   \
>>>> +        aml_append(_dev_, _method_);                                       \
>>>> +    } while (0)
>>> _STA doesn't have any logic here so drop macro and just
>>> replace its call sites with:
>>
>> Okay, I was just wanting to save some code lines. I will drop this macro.
>>
>>>
>>> aml_append(foo_dev, aml_name_decl("_STA", aml_int(0xf));
>>
>> _STA is required as a method with zero argument but this statement just
>> define a object. It is okay?
> Spec doesn't say that it must be method, it says that it will evaluate _STA object
> and result must be a combination of defined flags.
> AML wise calling a method with 0 arguments and referencing named variable
> is the same thing, both end up being just a namestring.

I just tested it, it works.

>
> Also note that _STA here return 0xF, and spec says that if _STA is missing
> OSPM shall assume its implicit value being 0xF, so you can just drop _STA
> object here altogether.

Actually, it will be needed for NVDIMM hotplug, but it is okay to me
to drop it at present. Let's introduce it when we implement hotplug.

>
>>
>>>
>>>
>>>> +
>>>> +#define BUILD_DSM_METHOD(_dev_, _method_, _handle_, _uuid_)                \
>>>> +    do {                                                                   \
>>>> +        Aml *ifctx, *uuid;                                                 \
>>>> +        _method_ = aml_method("_DSM", 4);                                  \
>>>> +        /* check UUID if it is we expect, return the errorcode if not.*/   \
>>>> +        uuid = aml_touuid(_uuid_);                                         \
>>>> +        ifctx = aml_if(aml_lnot(aml_equal(aml_arg(0), uuid)));             \
>>>> +        aml_append(ifctx, aml_return(aml_int(1 /* Not Supported */)));     \
>>>> +        aml_append(method, ifctx);                                         \
>>>> +        aml_append(method, aml_return(aml_call4("NCAL", aml_int(_handle_), \
>>>> +                   aml_arg(1), aml_arg(2), aml_arg(3))));                  \
>>>> +        aml_append(_dev_, _method_);                                       \
>>>> +    } while (0)
>>>> +
>>>> +#define BUILD_FIELD_UNIT_SIZE(_field_, _byte_, _name_)                     \
>>>> +    aml_append(_field_, aml_named_field(_name_, (_byte_) * BITS_PER_BYTE))
>>>> +
>>>> +#define BUILD_FIELD_UNIT_STRUCT(_field_, _s_, _f_, _name_)                 \
>>>> +    BUILD_FIELD_UNIT_SIZE(_field_, sizeof(typeof_field(_s_, _f_)), _name_)
>>>> +
>>>> +static void build_nvdimm_devices(GSList *device_list, Aml *root_dev)
>>>> +{
>>>> +    for (; device_list; device_list = device_list->next) {
>>>> +        NVDIMMDevice *nvdimm = device_list->data;
>>>> +        int slot = object_property_get_int(OBJECT(nvdimm), DIMM_SLOT_PROP,
>>>> +                                           NULL);
>>>> +        uint32_t handle = nvdimm_slot_to_handle(slot);
>>>> +        Aml *dev, *method;
>>>> +
>>>> +        dev = aml_device("NV%02X", slot);
>>>> +        aml_append(dev, aml_name_decl("_ADR", aml_int(handle)));
>>>> +
>>>> +        BUILD_STA_METHOD(dev, method);
>>>> +
>>>> +        /*
>>>> +         * Chapter 4: _DSM Interface for NVDIMM Device (non-root) - Example
>>>> +         * in DSM Spec Rev1.
>>>> +         */
>>>> +        BUILD_DSM_METHOD(dev, method,
>>>> +                         handle /* NVDIMM Device Handle */,
>>>> +                         "4309AC30-0D11-11E4-9191-0800200C9A66"
>>>> +                         /* UUID for NVDIMM Devices. */);
>>> this will add N-bytes * #NVDIMMS in worst case.
>>> Please drop macro and just consolidate this method into _DSM method of parent scope
>>> and then call it from here like this:
>>>      Method(_DSM, 4)
>>>          Return(^_DSM(Arg[0-3]))
>>
>> Parent _DSM can not be directly called as _DSM in parent requires different UUID.
>> UUID is not saved in dsm memory so that UUID verification should be done in AML.
>>
>> This macro, BUILD_DSM_METHOD(), build its _DSM call and check if UUID is valid, if
>> not, it returns error code 1 (Not Supoorted), otherwise it call the common method
>> NCAL which saves input parameters into dsm memory and trigger IO exit. It seems no
>> byte is wasted. No?
> add an extra arg to NCAL lets say IS_ROOT
> NCAL will check for root UUID if IS_ROOT true and
> check for nvdimm device UUID if it's false.
> That roughly will save ~150bytes per nvdimm or more than 2Kb in case of 256 NVDIMMs.

Okay, good to me.

>
>>
>>>
>>>> +
>>>> +        aml_append(root_dev, dev);
>>>> +    }
>>>> +}
>>>> +
>>>> +static void nvdimm_build_acpi_devices(GSList *device_list, Aml *sb_scope)
>>>> +{
>>>> +    Aml *dev, *method, *field;
>>>> +    uint64_t page_size = TARGET_PAGE_SIZE;
>>>> +
>>>> +    dev = aml_device("NVDR");
>>>> +    aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0012")));
>>>> +
>>>> +    /* map DSM memory and IO into ACPI namespace. */
>>>> +    aml_append(dev, aml_operation_region("NPIO", AML_SYSTEM_IO,
>>>> +               NVDIMM_ACPI_IO_BASE, NVDIMM_ACPI_IO_LEN));
>>>> +    aml_append(dev, aml_operation_region("NRAM", AML_SYSTEM_MEMORY,
>>>> +               NVDIMM_ACPI_MEM_BASE, page_size));
>>>> +
>>>> +    /*
>>>> +     * DSM notifier:
>>>> +     * @NOTI: Read it will notify QEMU that _DSM method is being
>>>> +     *        called and the parameters can be found in NvdimmDsmIn.
>>>> +     *        The value read from it is the buffer size of DSM output
>>>> +     *        filled by QEMU.
>>>> +     */
>>>> +    field = aml_field("NPIO", AML_DWORD_ACC, AML_PRESERVE);
>>>> +    BUILD_FIELD_UNIT_SIZE(field, sizeof(uint32_t), "NOTI");
>>>> +    aml_append(dev, field);
>>>> +
>>>> +    /*
>>>> +     * DSM input:
>>>> +     * @HDLE: store device's handle, it's zero if the _DSM call happens
>>>> +     *        on NVDIMM Root Device.
>>>> +     * @REVS: store the Arg1 of _DSM call.
>>>> +     * @FUNC: store the Arg2 of _DSM call.
>>>> +     * @ARG3: store the Arg3 of _DSM call.
>>>> +     *
>>>> +     * They are RAM mapping on host so that these accesses never cause
>>>> +     * VM-EXIT.
>>>> +     */
>>>> +    field = aml_field("NRAM", AML_DWORD_ACC, AML_PRESERVE);
>>>> +    BUILD_FIELD_UNIT_STRUCT(field, NvdimmDsmIn, handle, "HDLE");
>>>> +    BUILD_FIELD_UNIT_STRUCT(field, NvdimmDsmIn, revision, "REVS");
>>>> +    BUILD_FIELD_UNIT_STRUCT(field, NvdimmDsmIn, function, "FUNC");
>>>> +    BUILD_FIELD_UNIT_SIZE(field, page_size - offsetof(NvdimmDsmIn, arg3),
>>>> +                          "ARG3");
>>> These macros don't make code any better and one has to jump to their
>>> definition every time one sees it to figure out what it's doing.
>>> Please don't hide code behind macros and just replace them with aml_foo()
>>> here and at other places in this patch.
>>>
>>
>> Okay, will follow your way. :)
>>
>>>> +    aml_append(dev, field);
>>>> +
>>>> +    /*
>>>> +     * DSM output:
>>>> +     * @ODAT: the buffer QEMU uses to store the result, the actual size
>>>> +     *        filled by QEMU is the value read from NOT1.
>>>> +     *
>>>> +     * Since the page is reused by both input and out, the input data
>>>> +     * will be lost after storing new result into @ODAT.
>>>> +    */
>>>> +    field = aml_field("NRAM", AML_DWORD_ACC, AML_PRESERVE);
>>>> +    BUILD_FIELD_UNIT_SIZE(field, page_size, "ODAT");
>>>> +    aml_append(dev, field);
>>>> +
>>>> +    method = aml_method_serialized("NCAL", 4);
> Why method is called with 4 arguments but only arg[0-2] are used?

The arg3 is used in the later patch:
[PATCH v7 28/35] nvdimm acpi: save arg3 for NVDIMM device _DSM method

>
>>>> +    {
>>>> +        Aml *buffer_size = aml_local(0);
>>>> +
>>>> +        aml_append(method, aml_store(aml_arg(0), aml_name("HDLE")));
>>>> +        aml_append(method, aml_store(aml_arg(1), aml_name("REVS")));
>>>> +        aml_append(method, aml_store(aml_arg(2), aml_name("FUNC")));
>>>> +
>>>> +        /*
>>>> +         * transfer control to QEMU and the buffer size filled by
>>>> +         * QEMU is returned.
>>>> +         */
>>>> +        aml_append(method, aml_store(aml_name("NOTI"), buffer_size));
>>>> +
>>>> +        aml_append(method, aml_store(aml_shiftleft(buffer_size,
>>>> +                                       aml_int(3)), buffer_size));
>>>> +
>>>> +        aml_append(method, aml_create_field(aml_name("ODAT"), aml_int(0),
>>>> +                                            buffer_size , "OBUF"));
>>>> +        aml_append(method, aml_concatenate(aml_buffer(0, NULL),
>>>> +                                           aml_name("OBUF"), aml_local(1)));
>>>> +        aml_append(method, aml_return(aml_local(1)));
>>>> +    }
>>>> +    aml_append(dev, method);
>>>> +
>>>> +    BUILD_STA_METHOD(dev, method);
>>>> +
>>>> +    /*
>>>> +     * Chapter 3: _DSM Interface for NVDIMM Root Device - Example in DSM
>>>> +     * Spec Rev1.
>>>> +     */
>>>> +    BUILD_DSM_METHOD(dev, method,
>>>> +                     0 /* 0 is reserved for NVDIMM Root Device*/,
> Does 'handle' equal to slot number?

handle = slot + 1, to reserve 0 for NVDIMM root device:

/*
  * handle is used to uniquely associate nfit_memdev structure with NVDIMM
  * ACPI device - nfit_memdev.nfit_handle matches with the value returned
  * by ACPI device _ADR method.
  *
  * We generate the handle with the slot id of NVDIMM device and reserve
  * 0 for NVDIMM root device.
  */
static uint32_t nvdimm_slot_to_handle(int slot)
{
     return slot + 1;
}

>
>
>>>> +                     "2F10E7A4-9E91-11E4-89D3-123B93F75CBA"
>>>> +                     /* UUID for NVDIMM Root Devices. */);
>>>> +
>>>> +    build_nvdimm_devices(device_list, dev);
>>>> +
>>>> +    aml_append(sb_scope, dev);
>>>> +}
>>>> +
>>>> +static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
>>>> +                              GArray *table_data, GArray *linker)
>>>> +{
>>>> +    Aml *ssdt, *sb_scope;
>>>> +
>>>> +    acpi_add_table(table_offsets, table_data);
>>>> +
>>>> +    ssdt = init_aml_allocator();
>>>> +    acpi_data_push(ssdt->buf, sizeof(AcpiTableHeader));
>>>> +
>>>> +    sb_scope = aml_scope("\\_SB");
>>>> +    nvdimm_build_acpi_devices(device_list, sb_scope);
>>> is there need for dedicated nvdimm_build_acpi_devices()?
>>> Is it reused somewhere else?
>>> If it's not then just inline it here.
>>
>> Since building NVDIMM devices is a complex work so i designed to
>> let nvdimm_build_acpi_devices() build NVDIMM root device then
>> it calls build_nvdimm_devices() to build children devices. You
>> can see nvdimm_build_acpi_devices is a big function.
>>
>> That proposal just wants to make the code clear. If you really
>> hate this, i will drop nvdimm_build_acpi_devices, no problem. :)
> seeing how much this function will add to nvdimm_build_acpi_devices,
> I don't see point in having a separate nvdimm_build_acpi_devices().
>

Well, let's happily drop it.