Re: [Qemu-devel] [PATCH v3 3/4] nvdimm acpi: introduce _FIT

[Xiao Guangrong]

On 11/02/2016 09:56 PM, Igor Mammedov wrote:
> On Sat, 29 Oct 2016 00:35:39 +0800
> Xiao Guangrong <address@hidden> 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 UUID is UUID
> > 648B9CF2-CDA1-4312-8AD9-49C4AF32BD62, handle 0x10000, function index
> > is 0x1, is reserved by QEMU to read the piece of FIT buffer. The buffer
> > is concatenated before _FIT return
> >
> > Refer to docs/specs/acpi-nvdimm.txt for detailed design
> >
> > Signed-off-by: Xiao Guangrong <address@hidden>
> > ---
> [...]
>
> > diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> > index 5f728a6..fc1a012 100644
> > --- a/hw/acpi/nvdimm.c
> > +++ b/hw/acpi/nvdimm.c
> > @@ -496,6 +496,22 @@ typedef struct NvdimmFuncSetLabelDataIn 
> > NvdimmFuncSetLabelDataIn;
> >  QEMU_BUILD_BUG_ON(sizeof(NvdimmFuncSetLabelDataIn) +
> >                    offsetof(NvdimmDsmIn, arg3) > 4096);
> >
> > +struct NvdimmFuncReadFITIn {
> > +    uint32_t offset; /* the offset of FIT buffer. */
> > +} QEMU_PACKED;
> > +typedef struct NvdimmFuncReadFITIn NvdimmFuncReadFITIn;
> > +QEMU_BUILD_BUG_ON(sizeof(NvdimmFuncReadFITIn) +
> > +                  offsetof(NvdimmDsmIn, arg3) > 4096);
> > +
> > +struct NvdimmFuncReadFITOut {
> > +    /* the size of buffer filled by QEMU. */
> > +    uint32_t len;
> > +    uint32_t func_ret_status; /* return status code. */
> > +    uint8_t fit[0]; /* the FIT data. */
> > +} QEMU_PACKED;
> > +typedef struct NvdimmFuncReadFITOut NvdimmFuncReadFITOut;
> > +QEMU_BUILD_BUG_ON(sizeof(NvdimmFuncReadFITOut) > 4096);
> > +
> >  static void
> >  nvdimm_dsm_function0(uint32_t supported_func, hwaddr dsm_mem_addr)
> >  {
> > @@ -516,6 +532,74 @@ nvdimm_dsm_no_payload(uint32_t func_ret_status, hwaddr 
> > dsm_mem_addr)
> >      cpu_physical_memory_write(dsm_mem_addr, &out, sizeof(out));
> >  }
> >
> > +#define NVDIMM_QEMU_RSVD_HANDLE_ROOT 0x10000
> > +
> > +/* Read FIT data, defined in docs/specs/acpi_nvdimm.txt. */
> > +static void nvdimm_dsm_func_read_fit(AcpiNVDIMMState *state, NvdimmDsmIn *in,
> > +                                     hwaddr dsm_mem_addr)
> > +{
> > +    NvdimmFitBuffer *fit_buf = &state->fit_buf;
> > +    NvdimmFuncReadFITIn *read_fit;
> > +    NvdimmFuncReadFITOut *read_fit_out;
> > +    GArray *fit;
> > +    uint32_t read_len = 0, func_ret_status;
> > +    int size;
> > +
> > +    read_fit = (NvdimmFuncReadFITIn *)in->arg3;
> > +    le32_to_cpus(&read_fit->offset);
> I'd prefer if you'd not do inplace conversion, just do
> offset = le32_to_cpu(read_fit->offset);

okay.

> > +
> > +    qemu_mutex_lock(&fit_buf->lock);
> > +    fit = fit_buf->fit;
> > +
> > +    nvdimm_debug("Read FIT: offset %#x FIT size %#x Dirty %s.\n",
> > +                 read_fit->offset, fit->len, fit_buf->dirty ? "Yes" : "No");
> as follow up path replace nvdimm_debug() with trace events

I will do it as a separate patch.

> > +
> > +    if (read_fit->offset > fit->len) {
> > +        func_ret_status = 3 /* Invalid Input Parameters */;
> should be macros instead of magic value

Yes.

> > +        goto exit;
> > +    }
> > +
> > +    /* It is the first time to read FIT. */
> > +    if (!read_fit->offset) {
> > +        fit_buf->dirty = false;
> > +    } else if (fit_buf->dirty) { /* FIT has been changed during RFIT. */
> > +        func_ret_status = 0x100 /* fit changed */;
> should be macros instead of magic value

okay.

> > +        goto exit;
> > +    }
> > +
> > +    func_ret_status = 0 /* Success */;
> > +    read_len = MIN(fit->len - read_fit->offset,
> > +                   4096 - sizeof(NvdimmFuncReadFITOut));
> > +
> > +exit:
> > +    size = sizeof(NvdimmFuncReadFITOut) + read_len;
> > +    read_fit_out = g_malloc(size);
> > +
> > +    read_fit_out->len = cpu_to_le32(size);
> > +    read_fit_out->func_ret_status = cpu_to_le32(func_ret_status);
> > +    memcpy(read_fit_out->fit, fit->data + read_fit->offset, read_len);
> > +
> > +    cpu_physical_memory_write(dsm_mem_addr, read_fit_out, size);
> > +
> > +    g_free(read_fit_out);
> > +    qemu_mutex_unlock(&fit_buf->lock);
> > +}
> > +
> > +static void nvdimm_dsm_reserved_root(AcpiNVDIMMState *state, NvdimmDsmIn *in,
> > +                                     hwaddr dsm_mem_addr)
> > +{
> > +    switch (in->function) {
> > +    case 0x0:
> > +        nvdimm_dsm_function0(0x1 | 1 << 1 /* Read FIT */, dsm_mem_addr);
> > +        return;
> > +    case 0x1 /*Read FIT */:
> > +        nvdimm_dsm_func_read_fit(state, in, dsm_mem_addr);
> > +        return;
> > +    }
> > +
> > +    nvdimm_dsm_no_payload(1 /* Not Supported */, dsm_mem_addr);
> should be macros instead of magic value

Okay.

> > +}
> > +
> >  static void nvdimm_dsm_root(NvdimmDsmIn *in, hwaddr dsm_mem_addr)
> >  {
> >      /*
> > @@ -742,6 +826,7 @@ nvdimm_dsm_read(void *opaque, hwaddr addr, unsigned size)
> >  static void
> >  nvdimm_dsm_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
> >  {
> > +    AcpiNVDIMMState *state = opaque;
> >      NvdimmDsmIn *in;
> >      hwaddr dsm_mem_addr = val;
> >
> > @@ -769,6 +854,11 @@ nvdimm_dsm_write(void *opaque, hwaddr addr, uint64_t val, 
> > unsigned size)
> >          goto exit;
> >      }
> >
> > +    if (in->handle == NVDIMM_QEMU_RSVD_HANDLE_ROOT) {
> > +        nvdimm_dsm_reserved_root(state, in, dsm_mem_addr);
> > +        goto exit;
> > +    }
> > +
> >       /* Handle 0 is reserved for NVDIMM Root Device. */
> >      if (!in->handle) {
> >          nvdimm_dsm_root(in, dsm_mem_addr);
> > @@ -821,9 +911,13 @@ void nvdimm_init_acpi_state(AcpiNVDIMMState *state, 
> > MemoryRegion *io,
> >  #define NVDIMM_DSM_OUT_BUF_SIZE "RLEN"
> >  #define NVDIMM_DSM_OUT_BUF      "ODAT"
> >
> > +#define NVDIMM_DSM_RFIT_STATUS  "RSTA"
> > +
> > +#define NVDIMM_QEMU_RSVD_UUID   "648B9CF2-CDA1-4312-8AD9-49C4AF32BD62"
> > +
> >  static void nvdimm_build_common_dsm(Aml *dev)
> >  {
> > -    Aml *method, *ifctx, *function, *handle, *uuid, *dsm_mem;
> > +    Aml *method, *ifctx, *function, *handle, *uuid, *dsm_mem, *elsectx2;
> >      Aml *elsectx, *unsupport, *unpatched, *expected_uuid, *uuid_invalid;
> >      Aml *pckg, *pckg_index, *pckg_buf, *field, *dsm_out_buf, *dsm_out_buf_size;
> >      uint8_t byte_list[1];
> > @@ -912,9 +1006,15 @@ static void nvdimm_build_common_dsm(Aml *dev)
> >                 /* UUID for NVDIMM Root Device */, expected_uuid));
> >      aml_append(method, ifctx);
> >      elsectx = aml_else();
> > -    aml_append(elsectx, aml_store(
> > +    ifctx = aml_if(aml_equal(handle, aml_int(NVDIMM_QEMU_RSVD_HANDLE_ROOT)));
> > +    aml_append(ifctx, aml_store(aml_touuid(NVDIMM_QEMU_RSVD_UUID
> > +               /* UUID for QEMU internal use */), expected_uuid));
> > +    aml_append(elsectx, ifctx);
> > +    elsectx2 = aml_else();
> > +    aml_append(elsectx2, aml_store(
> >                 aml_touuid("4309AC30-0D11-11E4-9191-0800200C9A66")
> >                 /* UUID for NVDIMM Devices */, expected_uuid));
> > +    aml_append(elsectx, elsectx2);
> >      aml_append(method, elsectx);
> >
> >      uuid_invalid = aml_lnot(aml_equal(uuid, expected_uuid));
> > @@ -994,6 +1094,105 @@ static void nvdimm_build_device_dsm(Aml *dev, uint32_t 
> > handle)
> >      aml_append(dev, method);
> >  }
> >
> > +static void nvdimm_build_fit(Aml *dev)
> nvdimm_build_fit_method()

okay.

> > +{
> > +    Aml *method, *pkg, *buf, *buf_size, *offset, *call_result;
> > +    Aml *whilectx, *ifcond, *ifctx, *elsectx, *fit;
> > +
> > +    buf = aml_local(0);
> > +    buf_size = aml_local(1);
> > +    fit = aml_local(2);
> > +
> > +    aml_append(dev, aml_create_dword_field(aml_buffer(4, NULL),
> > +               aml_int(0), NVDIMM_DSM_RFIT_STATUS));
> it doesn't have to be buffer as it's internal ASL integer object
> so it could be just named variable.

Let me try.

> I'd also move it to _FIT method instead of making it device global

We can not as it is used both in _FIT method and RFIT method.

> and if it could work try to pass it as argument to RFIT
> RefOf/DerefOf may help here
> or make return value instead of buffer and pass buffer as reference.

Let me try.

> Alternatively you can return buffer from RFIT with status field included
> and check/discard status value there.

As we can not create name object in a while-loop, it is not easy to check
the status in _FIT.

> > +
> > +    /* build helper function, RFIT. */
> > +    method = aml_method("RFIT", 1, AML_SERIALIZED);
> > +    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(NVDIMM_QEMU_RSVD_UUID),
> > +                            aml_int(1) /* Revision 1 */,
> > +                            aml_int(0x1) /* Read FIT */,
> > +                            pkg, aml_int(NVDIMM_QEMU_RSVD_HANDLE_ROOT));
> > +    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"));
> > +
> > +    aml_append(method, aml_store(aml_name("STAU"),
> > +                                 aml_name(NVDIMM_DSM_RFIT_STATUS)));
> > +
> > +     /* 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));
> > +
> > +    /* 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));
> there isn't need to convert bytes to bits and store it in the same variable
> it creates confusion

Okay, i will introduce a new variable named buf_size_bits.

> > +    aml_append(method, aml_create_field(buf,
> > +                            aml_int(4 * BITS_PER_BYTE), /* offset at byte 4.*/
> > +                            buf_size, "BUFF"));
> just inline conversion in aml_create_field()

okay.