Re: [edk2-devel] [edk2-libc Patch 1/1] edk2-libc:add rdmsr_ex & wrmsr_ex functions to read/write cpu specific msrs

["Michael D Kinney" <michael.d.kinney@intel.com>]

Hi JP,

Is there a reason switch BSP is being used.  That is not a common operation
and is typically used if the current BSP is not stable or there is a good
reason to switch the BSP for OS boot.

The MP Services can be used to execute a C function on APs to execute
MSR related instructions.

Mike

> -----Original Message-----
> From: Jayaprakash, N <n.jayaprakash@intel.com>
> Sent: Sunday, April 14, 2024 10:33 PM
> To: devel@edk2.groups.io; Jayaprakash, N <n.jayaprakash@intel.com>
> Cc: Rebecca Cran <rebecca@bsdio.com>; Kinney, Michael D
> <michael.d.kinney@intel.com>
> Subject: RE: [edk2-devel] [edk2-libc Patch 1/1] edk2-libc:add rdmsr_ex
> & wrmsr_ex functions to read/write cpu specific msrs
> 
> + Rebecca and Mike,
> 
> Would you be able to review this PR?
> 
> Regards,
> JP
> 
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> Jayaprakash, N
> Sent: Wednesday, April 10, 2024 11:49 AM
> To: devel@edk2.groups.io
> Cc: Jayaprakash, N <n.jayaprakash@intel.com>; Rebecca Cran
> <rebecca@bsdio.com>; Kinney, Michael D <michael.d.kinney@intel.com>
> Subject: [edk2-devel] [edk2-libc Patch 1/1] edk2-libc:add rdmsr_ex &
> wrmsr_ex functions to read/write cpu specific msrs
> 
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4746
> 
> The rdmsr_ex and wrmsr_ex are extension APIs to the rdmsr and wrmsr
> APIs supported in edk2 module. These extension APIs makes it possible
> to read / write MSRs from specific processors and fills an existing
> gap in this area.
> 
> Cc: Rebecca Cran <rebecca@bsdio.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Jayaprakash N <n.jayaprakash@intel.com>
> Signed-off-by: Jayaprakash N <n.jayaprakash@intel.com>
> ---
>  .../PyMod-3.6.8/Modules/edk2module.c          | 159
> +++++++++++++++++-
>  .../Python/Python-3.6.8/Python368.inf         |   3 +
>  2 files changed, 158 insertions(+), 4 deletions(-)
> 
> diff --git a/AppPkg/Applications/Python/Python-3.6.8/PyMod-
> 3.6.8/Modules/edk2module.c b/AppPkg/Applications/Python/Python-
> 3.6.8/PyMod-3.6.8/Modules/edk2module.c
> index d6af8da..f1b13a6 100644
> --- a/AppPkg/Applications/Python/Python-3.6.8/PyMod-
> 3.6.8/Modules/edk2module.c
> +++ b/AppPkg/Applications/Python/Python-3.6.8/PyMod-
> 3.6.8/Modules/edk2mo
> +++ dule.c
> @@ -3,7 +3,7 @@
>      Derived from posixmodule.c in Python 2.7.2.
> 
>      Copyright (c) 2015, Daryl McDaniel. All rights reserved.<BR>
> -    Copyright (c) 2011 - 2023, Intel Corporation. All rights
> reserved.<BR>
> +    Copyright (c) 2011 - 2024, Intel Corporation. All rights
> + reserved.<BR>
>      This program and the accompanying materials are licensed and made
> available under
>      the terms and conditions of the BSD License that accompanies this
> distribution.
>      The full text of the license may be found at @@ -22,16 +22,23 @@
> #include  <wchar.h>  #include  <sys/syslimits.h>  #include  <Uefi.h>
> +#include  <Pi/PiDxeCis.h>      // Needed for the definition of
> EFI_AP_PROCEDURE
>  #include  <Library/UefiLib.h>
>  #include  <Library/PciLib.h>
>  #include  <Library/IoLib.h>
>  #include  <Library/UefiRuntimeServicesTableLib.h>
> +#include  <Library/UefiBootServicesTableLib.h>
> +#include  <Protocol/MpService.h>
> 
>  #ifdef __cplusplus
>  extern "C" {
>  #endif
> 
>  PyTypeObject EfiGuidType;
> +EFI_MP_SERVICES_PROTOCOL   *gpMpService = NULL;
> +UINTN                       gBSPProcessorNumber = 0;
> +UINTN                       gNumberOfProcessors = 0;
> +UINTN                       gNumberOfEnabledProcessors = 0;
> 
>  extern void _swsmi( unsigned int smi_code_data, unsigned int
> rax_value, unsigned int rbx_value, unsigned int rcx_value, unsigned
> int rdx_value, unsigned int rsi_value, unsigned int rdi_value );  // -
> - Support routines @@ -169,6 +176,35 @@ PyDoc_STRVAR(edk2__doc__,
>  /* dummy version. _PyVerify_fd() is already defined in fileobject.h
> */  #define _PyVerify_fd_dup2(A, B) (1)
> 
> +static EFI_STATUS
> +MpServicesWhoAmI (
> +  IN EFI_MP_SERVICES_PROTOCOL  *pMpService,
> +  OUT UINTN                    *pProcessorNumber
> +  )
> +{
> +  return pMpService->WhoAmI (pMpService, pProcessorNumber); }
> +
> +static EFI_STATUS
> +MpServicesGetNumberOfProcessors (
> +  IN EFI_MP_SERVICES_PROTOCOL  *pMpService,
> +  OUT UINTN                    *pNumberOfProcessors,
> +  OUT UINTN                    *pNumberOfEnabledProcessors
> +
> +  )
> +{
> +  return pMpService->GetNumberOfProcessors (pMpService,
> +pNumberOfProcessors, pNumberOfEnabledProcessors); }
> +
> +static EFI_STATUS
> +MpServicesSwitchBSP (
> +  IN EFI_MP_SERVICES_PROTOCOL  *pMpService,
> +  IN UINTN                      ProcessorNumber
> +  )
> +{
> +  return pMpService->SwitchBSP(pMpService,  ProcessorNumber, TRUE); }
> +
>  #ifndef UEFI_C_SOURCE
>  /* Return a dictionary corresponding to the POSIX environment table
> */  extern char **environ; @@ -3865,6 +3901,56 @@ edk2_rdmsr(PyObject
> *self, PyObject *args)
>    return Py_BuildValue("(II)", (unsigned long)veax, (unsigned
> long)vedx);  }
> 
> +PyDoc_STRVAR(efi_rdmsr_ex__doc__,
> +"rdmsr_ex(cpu, msr) -> (lower_32bits, higher_32bits)\n\ \n\ Read the
> +given msr by switching to cpu and return the data as tuple.\n\ \n\
> +Parameters:\n\
> +    cpu - The cpu number in hex or int format\n\
> +    msr - The msr in hex or int format\n\ \n\ Return Value:\n\
> +    a tuple with lower and higher 32 bit values read from the msr\n\
> +");
> +
> +static PyObject *
> +edk2_rdmsr_ex(PyObject *self, PyObject *args) {
> +  unsigned int cpu, vecx, veax, vedx;
> +  unsigned int bsp_switched = 0;
> +  EFI_STATUS status = 0;
> +  UINT64   data = 0;
> +
> +  if (!PyArg_ParseTuple(args, "II", &cpu, &vecx))
> +    return NULL;
> +
> +  Py_BEGIN_ALLOW_THREADS
> +  if (cpu != gBSPProcessorNumber && cpu < gNumberOfProcessors)  {
> +    //switch the BSP to the cpu
> +    status = MpServicesSwitchBSP(gpMpService, cpu);
> +    if (!EFI_ERROR(status))
> +    {
> +        bsp_switched = 1;
> +    }
> +  }
> +
> +  data = AsmReadMsr64(vecx);
> +
> +  if (bsp_switched)
> +  {
> +    // switch BSP to the saved BSP processor
> +    MpServicesSwitchBSP(gpMpService, gBSPProcessorNumber);
> +    // update the saved BSP processor
> +    MpServicesWhoAmI(gpMpService, &gBSPProcessorNumber);
> +  }
> +  Py_END_ALLOW_THREADS
> +  veax = (UINT32)data;
> +  vedx = (UINT64)data >> 32;
> +  return Py_BuildValue("(II)", (unsigned long)veax, (unsigned
> +long)vedx); }
> +
>  PyDoc_STRVAR(efi_wrmsr__doc__,
>  "wrmsr(msr, lower_32bits, higher_32bits) -> None\n\  \n\ @@ -3889,6
> +3975,58 @@ edk2_wrmsr(PyObject *self, PyObject *args)
>    data = vedx << 32 | veax;
>    Py_BEGIN_ALLOW_THREADS
>    AsmWriteMsr64(vecx, data);
> +  Py_END_ALLOW_THREADS
> +  Py_INCREF(Py_None);
> +  return Py_None;
> +}
> +
> +PyDoc_STRVAR(efi_wrmsr_ex__doc__,
> +"wrmsr_ex(cpu, msr, lower_32bits, higher_32bits) -> None\n\ \n\
> Writes
> +higher_32bits:lower_32bits to the given msr.\n\ \n\ Parameters:\n\
> +    cpu - The cpu number in hex or int format\n\
> +    msr - The msr in hex or int format\n\
> +    lower_32bits - The lower 32 bit data for the msr\n\
> +    higher_32bits - The higher 32 bit data for the msr\n\ \n\ Return
> +Value:\n\
> +    None\n\
> +");
> +
> +static PyObject *
> +edk2_wrmsr_ex(PyObject *self, PyObject *args) {
> +  unsigned int cpu, msr, veax, vedx;
> +  unsigned int bsp_switched = 0;
> +  EFI_STATUS status = 0;
> +  UINT64   data = 0;
> +
> +  if (!PyArg_ParseTuple(args, "IIII", &cpu, &msr, &veax, &vedx))
> +    return NULL;
> +  data = (((UINT64)vedx) << 32) | veax;
> +
> +  Py_BEGIN_ALLOW_THREADS
> +  if (cpu != gBSPProcessorNumber && cpu < gNumberOfProcessors)  {
> +    //switch the BSP to the cpu
> +    status = MpServicesSwitchBSP(gpMpService, cpu);
> +    if (!EFI_ERROR(status))
> +    {
> +        bsp_switched = 1;
> +    }
> +  }
> +  // write to MSR
> +  AsmWriteMsr64(msr, data);
> +
> +  if (bsp_switched)
> +  {
> +    // switch BSP to the saved BSP processor
> +    MpServicesSwitchBSP(gpMpService, gBSPProcessorNumber);
> +    // update the saved BSP processor
> +    MpServicesWhoAmI(gpMpService, &gBSPProcessorNumber);  }
>    Py_END_ALLOW_THREADS
>    Py_INCREF(Py_None);
>    return Py_None;
> @@ -4576,7 +4714,9 @@ static PyMethodDef edk2_methods[] = {  #endif
>      {"abort",               edk2_abort,      METH_NOARGS,
> edk2_abort__doc__},
>      {"rdmsr",               edk2_rdmsr,                 METH_VARARGS,
> efi_rdmsr__doc__},
> +    {"rdmsr_ex",            edk2_rdmsr_ex,              METH_VARARGS,
> efi_rdmsr_ex__doc__},
>      {"wrmsr",               edk2_wrmsr,                 METH_VARARGS,
> efi_wrmsr__doc__},
> +    {"wrmsr_ex",            edk2_wrmsr_ex,              METH_VARARGS,
> efi_wrmsr_ex__doc__},
>      {"readpci",             edk2_readpci,               METH_VARARGS,
> efi_readpci__doc__},
>      {"writepci",            edk2_writepci,              METH_VARARGS,
> efi_writepci__doc__},
>      {"readmem",             posix_readmem,
> METH_VARARGS, efi_readmem__doc__},
> @@ -4813,13 +4953,24 @@ static struct PyModuleDef edk2module = {
> PyMODINIT_FUNC
>  PyEdk2__Init(void)
>  {
> -    PyObject *m;
> +    PyObject    *m;
> +    EFI_STATUS   Status = 0;
> 
>  #ifndef UEFI_C_SOURCE
>    PyObject *v;
>  #endif
> +    Status = gBS->LocateProtocol(&gEfiMpServiceProtocolGuid, NULL,
> &gpMpService);
> +    if (EFI_ERROR(Status))
> +    {
> +        printf("Unable to locate the Protocol MpServices protocol:
> %r\n", Status);
> +        return NULL;
> +    }
> +    // Get the current BSP processor number
> +    MpServicesWhoAmI(gpMpService, &gBSPProcessorNumber);
> +    // Get the number of processors
> +    MpServicesGetNumberOfProcessors(gpMpService,
> &gNumberOfProcessors,
> + &gNumberOfEnabledProcessors);
> 
> -	m = PyModule_Create(&edk2module);
> +    m = PyModule_Create(&edk2module);
>      if (m == NULL)
>          return m;
> 
> @@ -4870,7 +5021,7 @@ PyEdk2__Init(void)
>      //PyModule_AddObject(m, "statvfs_result",
>      //                   (PyObject*) &StatVFSResultType);
>      initialized = 1;
> -	return m;
> +    return m;
> 
>  }
> 
> diff --git a/AppPkg/Applications/Python/Python-3.6.8/Python368.inf
> b/AppPkg/Applications/Python/Python-3.6.8/Python368.inf
> index 8b7f677..eca98b5 100644
> --- a/AppPkg/Applications/Python/Python-3.6.8/Python368.inf
> +++ b/AppPkg/Applications/Python/Python-3.6.8/Python368.inf
> @@ -46,6 +46,9 @@
>    #BsdSocketLib
>    #EfiSocketLib
> 
> +[Protocols]
> +  gEfiMpServiceProtocolGuid           ## CONSUMES
> +
>  [FixedPcd]
>    gEfiMdePkgTokenSpaceGuid.PcdDebugPropertyMask|0x0F
>    gEfiMdePkgTokenSpaceGuid.PcdDebugPrintErrorLevel|0x80000040
> --
> 2.40.0.windows.1
> 
> 
> 
> 
> 



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