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

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

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?

>
>
>> +
>> +#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?

>
>> +
>> +        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);
>> +    {
>> +        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*/,
>> +                     "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. :)

>
>> +
>> +    aml_append(ssdt, sb_scope);
>> +    /* copy AML table into ACPI tables blob and patch header there */
>> +    g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
>> +    build_header(linker, table_data,
>> +        (void *)(table_data->data + table_data->len - ssdt->buf->len),
>> +        "SSDT", ssdt->buf->len, 1);
> It's not ok to have several SSDT tables with exact same signature.
> how about extending build_header(..., oem_table_id)?
> You can set it to NULL to get original behavior but provide NVDIMM
> specific id for this table. for example "NVDIMM"
>

Ah, i just noticed the ACPI spec says:
| each secondary system description table listed in the RSDT/XSDT with a unique OEM Table ID is
| loaded.
You are right.

Okay, i will extend this function, thanks for your suggestion.