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

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 2 Nov 2016 23:54:05 +0800
Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote:

> On 11/02/2016 09:56 PM, Igor Mammedov wrote:
> > On Sat, 29 Oct 2016 00:35:39 +0800
> > Xiao Guangrong <guangrong.xiao@linux.intel.com> 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 <guangrong.xiao@linux.intel.com>
> >> ---  
> > [...]
> >  
> >> 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.
index() method might help there
or even better create a separate method to extract dword from buffer
and call it from all other places where you do similar thing
instead of creating a bunch of fields.

> 
> >> +
> >> +    /* 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.
>