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

["Jayaprakash, N" <n.jayaprakash@intel.com>]

In the validation and debug scenarios, engineers tend to read MSRs and write to MSRs of different CPUs.
So we are providing a simple mechanism through these APIs to enable them to do these operations.

These APIs will be part of the edk2 module of the Python interpreter and will be used during the validation and debug scenarios only.

This is not for switching the BSP for OS boot. This is only used during the validation and debug use cases.

Regards,
JP
-----Original Message-----
From: Kinney, Michael D <michael.d.kinney@intel.com> 
Sent: Thursday, April 18, 2024 12:08 AM
To: Jayaprakash, N <n.jayaprakash@intel.com>; devel@edk2.groups.io
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

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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