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

[Igor Mammedov <imammedo@redhat.com>]

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.

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.

> 
> >
> >
> >> +
> >> +#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.

> 
> >
> >> +
> >> +        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?

> >> +    {
> >> +        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?


> >> +                     "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().


> 
> >
> >> +
> >> +    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.
> 
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