OvmfPkg/CpuHotplugSmm/Smbase.c

   1 /** @file
   2   SMBASE relocation for hot-plugged CPUs.
   3
   4   Copyright (c) 2020, Red Hat, Inc.
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7 **/
   8
   9 #include <Base.h>                             // BASE_1MB
  10 #include <Library/BaseMemoryLib.h>            // CopyMem()
  11 #include <Library/DebugLib.h>                 // DEBUG()
  12
  13 #include "Smbase.h"
  14
  15 extern CONST UINT8 mPostSmmPen[];
  16 extern CONST UINT16 mPostSmmPenSize;
  17
  18 /**
  19   Allocate a non-SMRAM reserved memory page for the Post-SMM Pen for hot-added
  20   CPUs.
  21
  22   This function may only be called from the entry point function of the driver.
  23
  24   @param[out] PenAddress   The address of the allocated (normal RAM) reserved
  25                            page.
  26
  27   @param[in] BootServices  Pointer to the UEFI boot services table. Used for
  28                            allocating the normal RAM (not SMRAM) reserved page.
  29
  30   @retval EFI_SUCCESS          Allocation successful.
  31
  32   @retval EFI_BAD_BUFFER_SIZE  The Post-SMM Pen template is not smaller than
  33                                EFI_PAGE_SIZE.
  34
  35   @return                      Error codes propagated from underlying services.
  36                                DEBUG_ERROR messages have been logged. No
  37                                resources have been allocated.
  38 **/
  39 EFI_STATUS
  40 SmbaseAllocatePostSmmPen (
  41   OUT UINT32                  *PenAddress,
  42   IN  CONST EFI_BOOT_SERVICES *BootServices
  43   )
  44 {
  45   EFI_STATUS           Status;
  46   EFI_PHYSICAL_ADDRESS Address;
  47
  48   //
  49   // The pen code must fit in one page, and the last byte must remain free for
  50   // signaling the SMM Monarch.
  51   //
  52   if (mPostSmmPenSize >= EFI_PAGE_SIZE) {
  53     Status = EFI_BAD_BUFFER_SIZE;
  54     DEBUG ((DEBUG_ERROR, "%a: mPostSmmPenSize=%u: %r\n", __FUNCTION__,
  55       mPostSmmPenSize, Status));
  56     return Status;
  57   }
  58
  59   Address = BASE_1MB - 1;
  60   Status = BootServices->AllocatePages (AllocateMaxAddress,
  61                            EfiReservedMemoryType, 1, &Address);
  62   if (EFI_ERROR (Status)) {
  63     DEBUG ((DEBUG_ERROR, "%a: AllocatePages(): %r\n", __FUNCTION__, Status));
  64     return Status;
  65   }
  66
  67   DEBUG ((DEBUG_INFO, "%a: Post-SMM Pen at 0x%Lx\n", __FUNCTION__, Address));
  68   *PenAddress = (UINT32)Address;
  69   return EFI_SUCCESS;
  70 }
  71
  72 /**
  73   Copy the Post-SMM Pen template code into the reserved page allocated with
  74   SmbaseAllocatePostSmmPen().
  75
  76   Note that this effects an "SMRAM to normal RAM" copy.
  77
  78   The SMM Monarch is supposed to call this function from the root MMI handler.
  79
  80   @param[in] PenAddress  The allocation address returned by
  81                          SmbaseAllocatePostSmmPen().
  82 **/
  83 VOID
  84 SmbaseReinstallPostSmmPen (
  85   IN UINT32 PenAddress
  86   )
  87 {
  88   CopyMem ((VOID *)(UINTN)PenAddress, mPostSmmPen, mPostSmmPenSize);
  89 }
  90
  91 /**
  92   Release the reserved page allocated with SmbaseAllocatePostSmmPen().
  93
  94   This function may only be called from the entry point function of the driver,
  95   on the error path.
  96
  97   @param[in] PenAddress    The allocation address returned by
  98                            SmbaseAllocatePostSmmPen().
  99
 100   @param[in] BootServices  Pointer to the UEFI boot services table. Used for
 101                            releasing the normal RAM (not SMRAM) reserved page.
 102 **/
 103 VOID
 104 SmbaseReleasePostSmmPen (
 105   IN UINT32                  PenAddress,
 106   IN CONST EFI_BOOT_SERVICES *BootServices
 107   )
 108 {
 109   BootServices->FreePages (PenAddress, 1);
 110 }