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From: "Dong, Eric" <eric.dong@intel.com>
To: Tom Lendacky <thomas.lendacky@amd.com>,
	"devel@edk2.groups.io" <devel@edk2.groups.io>
Cc: Brijesh Singh <brijesh.singh@amd.com>,
	Ard Biesheuvel <ard.biesheuvel@arm.com>,
	"Justen, Jordan L" <jordan.l.justen@intel.com>,
	Laszlo Ersek <lersek@redhat.com>,
	"Gao, Liming" <liming.gao@intel.com>,
	"Kinney, Michael D" <michael.d.kinney@intel.com>,
	"Ni, Ray" <ray.ni@intel.com>
Subject: Re: [PATCH v10 42/46] UefiCpuPkg: Allow AP booting under SEV-ES
Date: Wed, 15 Jul 2020 05:23:13 +0000	[thread overview]
Message-ID: <DM6PR11MB327443BAF0138B126CE9C3C8FE7E0@DM6PR11MB3274.namprd11.prod.outlook.com> (raw)
In-Reply-To: <1dab98378f132f176345756ed09a602c86dab6d6.1594736896.git.thomas.lendacky@amd.com>

Reviewed-by: Eric Dong <eric.dong@intel.com>

> -----Original Message-----
> From: Tom Lendacky <thomas.lendacky@amd.com>
> Sent: Tuesday, July 14, 2020 10:38 PM
> To: devel@edk2.groups.io
> Cc: Brijesh Singh <brijesh.singh@amd.com>; Ard Biesheuvel
> <ard.biesheuvel@arm.com>; Dong, Eric <eric.dong@intel.com>; Justen,
> Jordan L <jordan.l.justen@intel.com>; Laszlo Ersek <lersek@redhat.com>;
> Gao, Liming <liming.gao@intel.com>; Kinney, Michael D
> <michael.d.kinney@intel.com>; Ni, Ray <ray.ni@intel.com>
> Subject: [PATCH v10 42/46] UefiCpuPkg: Allow AP booting under SEV-ES
> 
> From: Tom Lendacky <thomas.lendacky@amd.com>
> 
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
> 
> Typically, an AP is booted using the INIT-SIPI-SIPI sequence. This sequence is
> intercepted by the hypervisor, which sets the AP's registers to the values
> requested by the sequence. At that point, the hypervisor can start the AP,
> which will then begin execution at the appropriate location.
> 
> Under SEV-ES, AP booting presents some challenges since the hypervisor is
> not allowed to alter the AP's register state. In this situation, we have to
> distinguish between the AP's first boot and AP's subsequent boots.
> 
> First boot:
>  Once the AP's register state has been defined (which is before the guest  is
> first booted) it cannot be altered. Should the hypervisor attempt to  alter the
> register state, the change would be detected by the hardware  and the
> VMRUN instruction would fail. Given this, the first boot for the  AP is
> required to begin execution with this initial register state, which  is typically
> the reset vector. This prevents the BSP from directing the  AP startup
> location through the INIT-SIPI-SIPI sequence.
> 
>  To work around this, the firmware will provide a build time reserved area
> that can be used as the initial IP value. The hypervisor can extract this
> location value by checking for the SEV-ES reset block GUID that must be
> located 48-bytes from the end of the firmware. The format of the SEV-ES
> reset block area is:
> 
>    0x00 - 0x01 - SEV-ES Reset IP
>    0x02 - 0x03 - SEV-ES Reset CS Segment Base[31:16]
>    0x04 - 0x05 - Size of the SEV-ES reset block
>    0x06 - 0x15 - SEV-ES Reset Block GUID
>                    (00f771de-1a7e-4fcb-890e-68c77e2fb44e)
> 
>    The total size is 22 bytes. Any expansion to this block must be done
>    by adding new values before existing values.
> 
>  The hypervisor will use the IP and CS values obtained from the SEV-ES  reset
> block to set as the AP's initial values. The CS Segment Base  represents the
> upper 16 bits of the CS segment base and must be left  shifted by 16 bits to
> form the complete CS segment base value.
> 
>  Before booting the AP for the first time, the BSP must initialize the  SEV-ES
> reset area. This consists of programming a FAR JMP instruction  to the
> contents of a memory location that is also located in the SEV-ES  reset area.
> The BSP must program the IP and CS values for the FAR JMP  based on values
> drived from the INIT-SIPI-SIPI sequence.
> 
> Subsequent boots:
>  Again, the hypervisor cannot alter the AP register state, so a method is
> required to take the AP out of halt state and redirect it to the desired  IP
> location. If it is determined that the AP is running in an SEV-ES  guest, then
> instead of calling CpuSleep(), a VMGEXIT is issued with the  AP Reset Hold
> exit code (0x80000004). The hypervisor will put the AP in  a halt state, waiting
> for an INIT-SIPI-SIPI sequence. Once the sequence  is recognized, the
> hypervisor will resume the AP. At this point the AP  must transition from the
> current 64-bit long mode down to 16-bit real  mode and begin executing at
> the derived location from the INIT-SIPI-SIPI  sequence.
> 
>  Another change is around the area of obtaining the (x2)APIC ID during AP
> startup. During AP startup, the AP can't take a #VC exception before the  AP
> has established a stack. However, the AP stack is set by using the  (x2)APIC ID,
> which is obtained through CPUID instructions. A CPUID  instruction will cause
> a #VC, so a different method must be used. The  GHCB protocol supports a
> method to obtain CPUID information from the  hypervisor through the GHCB
> MSR. This method does not require a stack,  so it is used to obtain the
> necessary CPUID information to determine the  (x2)APIC ID.
> 
> The new 16-bit protected mode GDT entry is used in order to transition from
> 64-bit long mode down to 16-bit real mode.
> 
> A new assembler routine is created that takes the AP from 64-bit long mode
> to 16-bit real mode.  This is located under 1MB in memory and transitions
> from 64-bit long mode to 32-bit compatibility mode to 16-bit protected mode
> and finally 16-bit real mode.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf |   3 +
>  UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf |   3 +
>  UefiCpuPkg/Library/MpInitLib/MpLib.h          |  60 ++++
>  UefiCpuPkg/Library/MpInitLib/DxeMpLib.c       |  70 +++-
>  UefiCpuPkg/Library/MpInitLib/MpLib.c          | 336 +++++++++++++++++-
>  UefiCpuPkg/Library/MpInitLib/PeiMpLib.c       |  19 +
>  UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c  |   2 +-
>  UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc   |   2 +-
>  .../Library/MpInitLib/Ia32/MpFuncs.nasm       |  15 +
>  UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc    |   4 +-
>  UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm | 239 +++++++++++++
>  11 files changed, 738 insertions(+), 15 deletions(-)
> 
> diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> index 583276595619..1771575c69c1 100644
> --- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> @@ -52,6 +52,7 @@ [LibraryClasses]
>    DebugAgentLib
>    SynchronizationLib
>    PcdLib
> +  VmgExitLib
> 
>  [Protocols]
>    gEfiTimerArchProtocolGuid                     ## SOMETIMES_CONSUMES
> @@ -72,4 +73,6 @@ [Pcd]
>    gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate                       ##
> SOMETIMES_CONSUMES
> 
> gUefiCpuPkgTokenSpaceGuid.PcdCpuApStatusCheckIntervalInMicroSeconds
> ## CONSUMES
>    gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled                          ##
> CONSUMES
> +  gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase                       ##
> SOMETIMES_CONSUMES
>    gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard                      ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase                           ##
> CONSUMES
> diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
> b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
> index 4b3d39fbf36c..34abf25d43cd 100644
> --- a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
> +++ b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
> @@ -51,6 +51,7 @@ [LibraryClasses]
>    SynchronizationLib
>    PeiServicesLib
>    PcdLib
> +  VmgExitLib
> 
>  [Pcd]
>    gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber        ##
> CONSUMES
> @@ -62,6 +63,8 @@ [Pcd]
>    gUefiCpuPkgTokenSpaceGuid.PcdCpuApLoopMode                       ##
> CONSUMES
>    gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate                   ##
> SOMETIMES_CONSUMES
>    gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled                      ## CONSUMES
> +  gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase                   ##
> SOMETIMES_CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase                       ##
> CONSUMES
> 
>  [Ppis]
>    gEdkiiPeiShadowMicrocodePpiGuid        ## SOMETIMES_CONSUMES
> diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h
> b/UefiCpuPkg/Library/MpInitLib/MpLib.h
> index 5b46c295b6b2..b1a9d99cb3eb 100644
> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
> @@ -173,6 +173,11 @@ typedef struct {
>    UINT8             *RelocateApLoopFuncAddress;
>    UINTN             RelocateApLoopFuncSize;
>    UINTN             ModeTransitionOffset;
> +  UINTN             SwitchToRealSize;
> +  UINTN             SwitchToRealOffset;
> +  UINTN             SwitchToRealNoNxOffset;
> +  UINTN             SwitchToRealPM16ModeOffset;
> +  UINTN             SwitchToRealPM16ModeSize;
>  } MP_ASSEMBLY_ADDRESS_MAP;
> 
>  typedef struct _CPU_MP_DATA  CPU_MP_DATA; @@ -211,6 +216,8 @@
> typedef struct {
>    // Enable5LevelPaging indicates whether 5-level paging is enabled in long
> mode.
>    //
>    BOOLEAN               Enable5LevelPaging;
> +  BOOLEAN               SevEsIsEnabled;
> +  UINTN                 GhcbBase;
>  } MP_CPU_EXCHANGE_INFO;
> 
>  #pragma pack()
> @@ -257,6 +264,7 @@ struct _CPU_MP_DATA {
>    UINT8                          ApLoopMode;
>    UINT8                          ApTargetCState;
>    UINT16                         PmCodeSegment;
> +  UINT16                         Pm16CodeSegment;
>    CPU_AP_DATA                    *CpuData;
>    volatile MP_CPU_EXCHANGE_INFO  *MpCpuExchangeInfo;
> 
> @@ -278,8 +286,47 @@ struct _CPU_MP_DATA {
>    BOOLEAN                        WakeUpByInitSipiSipi;
> 
>    BOOLEAN                        SevEsIsEnabled;
> +  UINTN                          SevEsAPBuffer;
> +  UINTN                          SevEsAPResetStackStart;
> +  CPU_MP_DATA                    *NewCpuMpData;
> +
> +  UINT64                         GhcbBase;
>  };
> 
> +#define AP_RESET_STACK_SIZE 64
> +
> +#pragma pack(1)
> +
> +typedef struct {
> +  UINT8   InsnBuffer[8];
> +  UINT16  Rip;
> +  UINT16  Segment;
> +} SEV_ES_AP_JMP_FAR;
> +
> +#pragma pack()
> +
> +/**
> +  Assembly code to move an AP from long mode to real mode.
> +
> +  Move an AP from long mode to real mode in preparation to invoking
> + the reset vector.  This is used for SEV-ES guests where a hypervisor
> + is not allowed to set the CS and RIP to point to the reset vector.
> +
> +  @param[in]  BufferStart  The reset vector target.
> +  @param[in]  Code16       16-bit protected mode code segment value.
> +  @param[in]  Code32       32-bit protected mode code segment value.
> +  @param[in]  StackStart   The start of a stack to be used for transitioning
> +                           from long mode to real mode.
> +**/
> +typedef
> +VOID
> +(EFIAPI AP_RESET) (
> +  IN UINTN    BufferStart,
> +  IN UINT16   Code16,
> +  IN UINT16   Code32,
> +  IN UINTN    StackStart
> +  );
> +
>  extern EFI_GUID mCpuInitMpLibHobGuid;
> 
>  /**
> @@ -385,6 +432,19 @@ GetModeTransitionBuffer (
>    IN UINTN                BufferSize
>    );
> 
> +/**
> +  Return the address of the SEV-ES AP jump table.
> +
> +  This buffer is required in order for an SEV-ES guest to transition
> + from  UEFI into an OS.
> +
> +  @return         Return SEV-ES AP jump table buffer
> +**/
> +UINTN
> +GetSevEsAPMemory (
> +  VOID
> +  );
> +
>  /**
>    This function will be called by BSP to wakeup AP.
> 
> diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> index 8ccddf8e9f9c..9115ff9e3e30 100644
> --- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> @@ -12,6 +12,8 @@
>  #include <Library/UefiBootServicesTableLib.h>
>  #include <Library/DebugAgentLib.h>
>  #include <Library/DxeServicesTableLib.h>
> +#include <Register/Amd/Fam17Msr.h>
> +#include <Register/Amd/Ghcb.h>
> 
>  #include <Protocol/Timer.h>
> 
> @@ -144,6 +146,39 @@ GetModeTransitionBuffer (
>    return (UINTN)StartAddress;
>  }
> 
> +/**
> +  Return the address of the SEV-ES AP jump table.
> +
> +  This buffer is required in order for an SEV-ES guest to transition
> + from  UEFI into an OS.
> +
> +  @return         Return SEV-ES AP jump table buffer
> +**/
> +UINTN
> +GetSevEsAPMemory (
> +  VOID
> +  )
> +{
> +  EFI_STATUS            Status;
> +  EFI_PHYSICAL_ADDRESS  StartAddress;
> +
> +  //
> +  // Allocate 1 page for AP jump table page  //  StartAddress =
> + BASE_4GB - 1;  Status = gBS->AllocatePages (
> +                  AllocateMaxAddress,
> +                  EfiReservedMemoryType,
> +                  1,
> +                  &StartAddress
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  DEBUG ((DEBUG_INFO, "Dxe: SevEsAPMemory = %lx\n", (UINTN)
> + StartAddress));
> +
> +  return (UINTN) StartAddress;
> +}
> +
>  /**
>    Checks APs status and updates APs status if needed.
> 
> @@ -218,6 +253,38 @@ CheckApsStatus (
>    }
>  }
> 
> +/**
> +  Get Protected mode code segment with 16-bit default addressing
> +  from current GDT table.
> +
> +  @return  Protected mode 16-bit code segment value.
> +**/
> +UINT16
> +GetProtectedMode16CS (
> +  VOID
> +  )
> +{
> +  IA32_DESCRIPTOR          GdtrDesc;
> +  IA32_SEGMENT_DESCRIPTOR  *GdtEntry;
> +  UINTN                    GdtEntryCount;
> +  UINT16                   Index;
> +
> +  Index = (UINT16) -1;
> +  AsmReadGdtr (&GdtrDesc);
> +  GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof
> +(IA32_SEGMENT_DESCRIPTOR);
> +  GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
> +  for (Index = 0; Index < GdtEntryCount; Index++) {
> +    if (GdtEntry->Bits.L == 0) {
> +      if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.DB == 0) {
> +        break;
> +      }
> +    }
> +    GdtEntry++;
> +  }
> +  ASSERT (Index != GdtEntryCount);
> +  return Index * 8;
> +}
> +
>  /**
>    Get Protected mode code segment from current GDT table.
> 
> @@ -238,7 +305,7 @@ GetProtectedModeCS (
>    GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
>    for (Index = 0; Index < GdtEntryCount; Index++) {
>      if (GdtEntry->Bits.L == 0) {
> -      if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.L == 0) {
> +      if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.DB == 1) {
>          break;
>        }
>      }
> @@ -300,6 +367,7 @@ MpInitChangeApLoopCallback (
> 
>    CpuMpData = GetCpuMpData ();
>    CpuMpData->PmCodeSegment = GetProtectedModeCS ();
> +  CpuMpData->Pm16CodeSegment = GetProtectedMode16CS ();
>    CpuMpData->ApLoopMode = PcdGet8 (PcdCpuApLoopMode);
>    mNumberToFinish = CpuMpData->CpuCount - 1;
>    WakeUpAP (CpuMpData, TRUE, 0, RelocateApLoop, NULL, TRUE); diff --git
> a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> index 2a3fbeef35f7..90416c81b616 100644
> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> @@ -9,6 +9,9 @@
>  **/
> 
>  #include "MpLib.h"
> +#include <Library/VmgExitLib.h>
> +#include <Register/Amd/Fam17Msr.h>
> +#include <Register/Amd/Ghcb.h>
> 
>  EFI_GUID mCpuInitMpLibHobGuid = CPU_INIT_MP_LIB_HOB_GUID;
> 
> @@ -291,6 +294,14 @@ GetApLoopMode (
>        //
>        ApLoopMode = ApInHltLoop;
>      }
> +
> +    if (PcdGetBool (PcdSevEsIsEnabled)) {
> +      //
> +      // For SEV-ES, force AP in Hlt-loop mode in order to use the GHCB
> +      // protocol for starting APs
> +      //
> +      ApLoopMode = ApInHltLoop;
> +    }
>    }
> 
>    if (ApLoopMode != ApInMwaitLoop) {
> @@ -587,6 +598,112 @@ InitializeApData (
>    SetApState (&CpuMpData->CpuData[ProcessorNumber], CpuStateIdle);  }
> 
> +/**
> +  Get Protected mode code segment with 16-bit default addressing
> +  from current GDT table.
> +
> +  @return  Protected mode 16-bit code segment value.
> +**/
> +STATIC
> +UINT16
> +GetProtectedMode16CS (
> +  VOID
> +  )
> +{
> +  IA32_DESCRIPTOR          GdtrDesc;
> +  IA32_SEGMENT_DESCRIPTOR  *GdtEntry;
> +  UINTN                    GdtEntryCount;
> +  UINT16                   Index;
> +
> +  Index = (UINT16) -1;
> +  AsmReadGdtr (&GdtrDesc);
> +  GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof
> +(IA32_SEGMENT_DESCRIPTOR);
> +  GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
> +  for (Index = 0; Index < GdtEntryCount; Index++) {
> +    if (GdtEntry->Bits.L == 0 &&
> +        GdtEntry->Bits.DB == 0 &&
> +        GdtEntry->Bits.Type > 8) {
> +      break;
> +    }
> +    GdtEntry++;
> +  }
> +  ASSERT (Index != GdtEntryCount);
> +  return Index * 8;
> +}
> +
> +/**
> +  Get Protected mode code segment with 32-bit default addressing
> +  from current GDT table.
> +
> +  @return  Protected mode 32-bit code segment value.
> +**/
> +STATIC
> +UINT16
> +GetProtectedMode32CS (
> +  VOID
> +  )
> +{
> +  IA32_DESCRIPTOR          GdtrDesc;
> +  IA32_SEGMENT_DESCRIPTOR  *GdtEntry;
> +  UINTN                    GdtEntryCount;
> +  UINT16                   Index;
> +
> +  Index = (UINT16) -1;
> +  AsmReadGdtr (&GdtrDesc);
> +  GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof
> +(IA32_SEGMENT_DESCRIPTOR);
> +  GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
> +  for (Index = 0; Index < GdtEntryCount; Index++) {
> +    if (GdtEntry->Bits.L == 0 &&
> +        GdtEntry->Bits.DB == 1 &&
> +        GdtEntry->Bits.Type > 8) {
> +      break;
> +    }
> +    GdtEntry++;
> +  }
> +  ASSERT (Index != GdtEntryCount);
> +  return Index * 8;
> +}
> +
> +/**
> +  Reset an AP when in SEV-ES mode.
> +
> +  If successful, this function never returns.
> +
> +  @param[in] Ghcb                 Pointer to the GHCB
> +  @param[in] CpuMpData            Pointer to CPU MP Data
> +
> +**/
> +STATIC
> +VOID
> +MpInitLibSevEsAPReset (
> +  IN GHCB                         *Ghcb,
> +  IN CPU_MP_DATA                  *CpuMpData
> +  )
> +{
> +  UINT16           Code16, Code32;
> +  AP_RESET         *APResetFn;
> +  UINTN            BufferStart;
> +  UINTN            StackStart;
> +
> +  Code16 = GetProtectedMode16CS ();
> +  Code32 = GetProtectedMode32CS ();
> +
> +  if (CpuMpData->WakeupBufferHigh != 0) {
> +    APResetFn = (AP_RESET *) (CpuMpData->WakeupBufferHigh +
> + CpuMpData->AddressMap.SwitchToRealNoNxOffset);
> +  } else {
> +    APResetFn = (AP_RESET *) (CpuMpData->MpCpuExchangeInfo-
> >BufferStart
> + + CpuMpData->AddressMap.SwitchToRealOffset);
> +  }
> +
> +  BufferStart = CpuMpData->MpCpuExchangeInfo->BufferStart;
> +  StackStart = CpuMpData->SevEsAPResetStackStart -
> +                 (AP_RESET_STACK_SIZE * GetApicId ());
> +
> +  //
> +  // This call never returns.
> +  //
> +  APResetFn (BufferStart, Code16, Code32, StackStart); }
> +
>  /**
>    This function will be called from AP reset code if BSP uses WakeUpAP.
> 
> @@ -648,7 +765,14 @@ ApWakeupFunction (
>        InitializeApData (CpuMpData, ProcessorNumber, BistData,
> ApTopOfStack);
>        ApStartupSignalBuffer = CpuMpData-
> >CpuData[ProcessorNumber].StartupApSignal;
> 
> -      InterlockedDecrement ((UINT32 *) &CpuMpData->MpCpuExchangeInfo-
> >NumApsExecuting);
> +      //
> +      // Delay decrementing the APs executing count when SEV-ES is enabled
> +      // to allow the APs to issue an AP_RESET_HOLD before the BSP possibly
> +      // performs another INIT-SIPI-SIPI sequence.
> +      //
> +      if (!CpuMpData->SevEsIsEnabled) {
> +        InterlockedDecrement ((UINT32 *) &CpuMpData-
> >MpCpuExchangeInfo->NumApsExecuting);
> +      }
>      } else {
>        //
>        // Execute AP function if AP is ready @@ -755,7 +879,52 @@
> ApWakeupFunction (
>        //
>        while (TRUE) {
>          DisableInterrupts ();
> -        CpuSleep ();
> +        if (CpuMpData->SevEsIsEnabled) {
> +          MSR_SEV_ES_GHCB_REGISTER  Msr;
> +          GHCB                      *Ghcb;
> +          UINT64                    Status;
> +          BOOLEAN                   DoDecrement;
> +
> +          if (CpuMpData->InitFlag == ApInitConfig) {
> +            DoDecrement = TRUE;
> +          }
> +
> +          while (TRUE) {
> +            Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
> +            Ghcb = Msr.Ghcb;
> +
> +            VmgInit (Ghcb);
> +
> +            if (DoDecrement) {
> +              DoDecrement = FALSE;
> +
> +              //
> +              // Perform the delayed decrement just before issuing the first
> +              // VMGEXIT with AP_RESET_HOLD.
> +              //
> +              InterlockedDecrement ((UINT32 *) &CpuMpData-
> >MpCpuExchangeInfo->NumApsExecuting);
> +            }
> +
> +            Status = VmgExit (Ghcb, SVM_EXIT_AP_RESET_HOLD, 0, 0);
> +            if ((Status == 0) && (Ghcb->SaveArea.SwExitInfo2 != 0)) {
> +              VmgDone (Ghcb);
> +              break;
> +            }
> +
> +            VmgDone (Ghcb);
> +          }
> +
> +          //
> +          // Awakened in a new phase? Use the new CpuMpData
> +          //
> +          if (CpuMpData->NewCpuMpData != NULL) {
> +            CpuMpData = CpuMpData->NewCpuMpData;
> +          }
> +
> +          MpInitLibSevEsAPReset (Ghcb, CpuMpData);
> +        } else {
> +          CpuSleep ();
> +        }
>          CpuPause ();
>        }
>      }
> @@ -868,6 +1037,9 @@ FillExchangeInfoData (
>    ExchangeInfo->Enable5LevelPaging = (BOOLEAN) (Cr4.Bits.LA57 == 1);
>    DEBUG ((DEBUG_INFO, "%a: 5-Level Paging = %d\n", gEfiCallerBaseName,
> ExchangeInfo->Enable5LevelPaging));
> 
> +  ExchangeInfo->SevEsIsEnabled  = CpuMpData->SevEsIsEnabled;
> +  ExchangeInfo->GhcbBase        = (UINTN) CpuMpData->GhcbBase;
> +
>    //
>    // Get the BSP's data of GDT and IDT
>    //
> @@ -894,8 +1066,9 @@ FillExchangeInfoData (
>    // EfiBootServicesCode to avoid page fault if NX memory protection is
> enabled.
>    //
>    if (CpuMpData->WakeupBufferHigh != 0) {
> -    Size = CpuMpData->AddressMap.RendezvousFunnelSize -
> -           CpuMpData->AddressMap.ModeTransitionOffset;
> +    Size = CpuMpData->AddressMap.RendezvousFunnelSize +
> +             CpuMpData->AddressMap.SwitchToRealSize -
> +             CpuMpData->AddressMap.ModeTransitionOffset;
>      CopyMem (
>        (VOID *)CpuMpData->WakeupBufferHigh,
>        CpuMpData->AddressMap.RendezvousFunnelAddress + @@ -948,7
> +1121,8 @@ BackupAndPrepareWakeupBuffer(
>    CopyMem (
>      (VOID *) CpuMpData->WakeupBuffer,
>      (VOID *) CpuMpData->AddressMap.RendezvousFunnelAddress,
> -    CpuMpData->AddressMap.RendezvousFunnelSize
> +    CpuMpData->AddressMap.RendezvousFunnelSize +
> +      CpuMpData->AddressMap.SwitchToRealSize
>      );
>  }
> 
> @@ -969,6 +1143,44 @@ RestoreWakeupBuffer(
>      );
>  }
> 
> +/**
> +  Calculate the size of the reset stack.
> +
> +  @return                 Total amount of memory required for stacks
> +**/
> +STATIC
> +UINTN
> +GetApResetStackSize (
> +  VOID
> +  )
> +{
> +  return AP_RESET_STACK_SIZE *
> +PcdGet32(PcdCpuMaxLogicalProcessorNumber);
> +}
> +
> +/**
> +  Calculate the size of the reset vector.
> +
> +  @param[in]  AddressMap  The pointer to Address Map structure.
> +
> +  @return                 Total amount of memory required for the AP reset area
> +**/
> +STATIC
> +UINTN
> +GetApResetVectorSize (
> +  IN MP_ASSEMBLY_ADDRESS_MAP  *AddressMap
> +  )
> +{
> +  UINTN  Size;
> +
> +  Size = ALIGN_VALUE (AddressMap->RendezvousFunnelSize +
> +                        AddressMap->SwitchToRealSize +
> +                        sizeof (MP_CPU_EXCHANGE_INFO),
> +                      CPU_STACK_ALIGNMENT);  Size +=
> + GetApResetStackSize ();
> +
> +  return Size;
> +}
> +
>  /**
>    Allocate reset vector buffer.
> 
> @@ -982,16 +1194,22 @@ AllocateResetVector (
>    UINTN           ApResetVectorSize;
> 
>    if (CpuMpData->WakeupBuffer == (UINTN) -1) {
> -    ApResetVectorSize = CpuMpData->AddressMap.RendezvousFunnelSize +
> -                          sizeof (MP_CPU_EXCHANGE_INFO);
> +    ApResetVectorSize = GetApResetVectorSize (&CpuMpData-
> >AddressMap);
> 
>      CpuMpData->WakeupBuffer      = GetWakeupBuffer (ApResetVectorSize);
>      CpuMpData->MpCpuExchangeInfo = (MP_CPU_EXCHANGE_INFO *)
> (UINTN)
> -                    (CpuMpData->WakeupBuffer + CpuMpData-
> >AddressMap.RendezvousFunnelSize);
> +                    (CpuMpData->WakeupBuffer +
> +                       CpuMpData->AddressMap.RendezvousFunnelSize +
> +                       CpuMpData->AddressMap.SwitchToRealSize);
>      CpuMpData->WakeupBufferHigh  = GetModeTransitionBuffer (
> -                                    CpuMpData->AddressMap.RendezvousFunnelSize -
> +                                    CpuMpData->AddressMap.RendezvousFunnelSize +
> +
> + CpuMpData->AddressMap.SwitchToRealSize -
>                                      CpuMpData->AddressMap.ModeTransitionOffset
>                                      );
> +    //
> +    // The reset stack starts at the end of the buffer.
> +    //
> +    CpuMpData->SevEsAPResetStackStart = CpuMpData->WakeupBuffer +
> + ApResetVectorSize;
>    }
>    BackupAndPrepareWakeupBuffer (CpuMpData);  } @@ -1006,7 +1224,80
> @@ FreeResetVector (
>    IN CPU_MP_DATA              *CpuMpData
>    )
>  {
> -  RestoreWakeupBuffer (CpuMpData);
> +  //
> +  // If SEV-ES is enabled, the reset area is needed for AP parking and
> +  // and AP startup in the OS, so the reset area is reserved. Do not
> +  // perform the restore as this will overwrite memory which has data
> +  // needed by SEV-ES.
> +  //
> +  if (!CpuMpData->SevEsIsEnabled) {
> +    RestoreWakeupBuffer (CpuMpData);
> +  }
> +}
> +
> +/**
> +  Allocate the SEV-ES AP jump table buffer.
> +
> +  @param[in, out]  CpuMpData  The pointer to CPU MP Data structure.
> +**/
> +VOID
> +AllocateSevEsAPMemory (
> +  IN OUT CPU_MP_DATA          *CpuMpData
> +  )
> +{
> +  if (CpuMpData->SevEsAPBuffer == (UINTN) -1) {
> +    CpuMpData->SevEsAPBuffer =
> +      CpuMpData->SevEsIsEnabled ? GetSevEsAPMemory () : 0;
> +  }
> +}
> +
> +/**
> +  Program the SEV-ES AP jump table buffer.
> +
> +  @param[in]  SipiVector  The SIPI vector used for the AP Reset **/
> +VOID SetSevEsJumpTable (
> +  IN UINTN  SipiVector
> +  )
> +{
> +  SEV_ES_AP_JMP_FAR *JmpFar;
> +  UINT32            Offset, InsnByte;
> +  UINT8             LoNib, HiNib;
> +
> +  JmpFar = (SEV_ES_AP_JMP_FAR *) FixedPcdGet32
> (PcdSevEsWorkAreaBase);
> + ASSERT (JmpFar != NULL);
> +
> +  //
> +  // Obtain the address of the Segment/Rip location in the workarea.
> +  // This will be set to a value derived from the SIPI vector and will
> + // be the memory address used for the far jump below.
> +  //
> +  Offset = FixedPcdGet32 (PcdSevEsWorkAreaBase);  Offset += sizeof
> + (JmpFar->InsnBuffer);  LoNib = (UINT8) Offset;  HiNib = (UINT8)
> + (Offset >> 8);
> +
> +  //
> +  // Program the workarea (which is the initial AP boot address) with
> + // far jump to the SIPI vector (where XX and YY represent the  //
> + address of where the SIPI vector is stored.
> +  //
> +  //   JMP FAR [CS:XXYY] => 2E FF 2E YY XX
> +  //
> +  InsnByte = 0;
> +  JmpFar->InsnBuffer[InsnByte++] = 0x2E;  // CS override prefix
> + JmpFar->InsnBuffer[InsnByte++] = 0xFF;  // JMP (FAR)
> + JmpFar->InsnBuffer[InsnByte++] = 0x2E;  // ModRM (JMP memory location)
> + JmpFar->InsnBuffer[InsnByte++] = LoNib; // YY offset ...
> +  JmpFar->InsnBuffer[InsnByte++] = HiNib; // XX offset ...
> +
> +  //
> +  // Program the Segment/Rip based on the SIPI vector (always at least
> + // 16-byte aligned, so Rip is set to 0).
> +  //
> +  JmpFar->Rip = 0;
> +  JmpFar->Segment = (UINT16) (SipiVector >> 4);
>  }
> 
>  /**
> @@ -1043,6 +1334,7 @@ WakeUpAP (
>        CpuMpData->InitFlag   != ApInitDone) {
>      ResetVectorRequired = TRUE;
>      AllocateResetVector (CpuMpData);
> +    AllocateSevEsAPMemory (CpuMpData);
>      FillExchangeInfoData (CpuMpData);
>      SaveLocalApicTimerSetting (CpuMpData);
>    }
> @@ -1079,6 +1371,15 @@ WakeUpAP (
>        }
>      }
>      if (ResetVectorRequired) {
> +      //
> +      // For SEV-ES, the initial AP boot address will be defined by
> +      // PcdSevEsWorkAreaBase. The Segment/Rip must be the jump address
> +      // from the original INIT-SIPI-SIPI.
> +      //
> +      if (CpuMpData->SevEsIsEnabled) {
> +        SetSevEsJumpTable (ExchangeInfo->BufferStart);
> +      }
> +
>        //
>        // Wakeup all APs
>        //
> @@ -1170,6 +1471,16 @@ WakeUpAP (
>      *(UINT32 *) CpuData->StartupApSignal = WAKEUP_AP_SIGNAL;
>      if (ResetVectorRequired) {
>        CpuInfoInHob = (CPU_INFO_IN_HOB *) (UINTN) CpuMpData-
> >CpuInfoInHob;
> +
> +      //
> +      // For SEV-ES, the initial AP boot address will be defined by
> +      // PcdSevEsWorkAreaBase. The Segment/Rip must be the jump address
> +      // from the original INIT-SIPI-SIPI.
> +      //
> +      if (CpuMpData->SevEsIsEnabled) {
> +        SetSevEsJumpTable (ExchangeInfo->BufferStart);
> +      }
> +
>        SendInitSipiSipi (
>          CpuInfoInHob[ProcessorNumber].ApicId,
>          (UINT32) ExchangeInfo->BufferStart @@ -1646,7 +1957,7 @@
> MpInitLibInitialize (
>    ASSERT (MaxLogicalProcessorNumber != 0);
> 
>    AsmGetAddressMap (&AddressMap);
> -  ApResetVectorSize = AddressMap.RendezvousFunnelSize + sizeof
> (MP_CPU_EXCHANGE_INFO);
> +  ApResetVectorSize = GetApResetVectorSize (&AddressMap);
>    ApStackSize = PcdGet32(PcdCpuApStackSize);
>    ApLoopMode  = GetApLoopMode (&MonitorFilterSize);
> 
> @@ -1705,6 +2016,8 @@ MpInitLibInitialize (
>    CpuMpData->CpuInfoInHob     = (UINT64) (UINTN) (CpuMpData->CpuData
> + MaxLogicalProcessorNumber);
>    InitializeSpinLock(&CpuMpData->MpLock);
>    CpuMpData->SevEsIsEnabled = PcdGetBool (PcdSevEsIsEnabled);
> +  CpuMpData->SevEsAPBuffer  = (UINTN) -1;
> +  CpuMpData->GhcbBase       = PcdGet64 (PcdGhcbBase);
> 
>    //
>    // Make sure no memory usage outside of the allocated buffer.
> @@ -1763,6 +2076,7 @@ MpInitLibInitialize (
>      // APs have been wakeup before, just get the CPU Information
>      // from HOB
>      //
> +    OldCpuMpData->NewCpuMpData = CpuMpData;
>      CpuMpData->CpuCount  = OldCpuMpData->CpuCount;
>      CpuMpData->BspNumber = OldCpuMpData->BspNumber;
>      CpuMpData->CpuInfoInHob = OldCpuMpData->CpuInfoInHob; diff --git
> a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> index a548fed23fa7..3989bd6a7a9f 100644
> --- a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> @@ -280,6 +280,25 @@ GetModeTransitionBuffer (
>    return 0;
>  }
> 
> +/**
> +  Return the address of the SEV-ES AP jump table.
> +
> +  This buffer is required in order for an SEV-ES guest to transition
> + from  UEFI into an OS.
> +
> +  @return         Return SEV-ES AP jump table buffer
> +**/
> +UINTN
> +GetSevEsAPMemory (
> +  VOID
> +  )
> +{
> +  //
> +  // PEI phase doesn't need to do such transition. So simply return 0.
> +  //
> +  return 0;
> +}
> +
>  /**
>    Checks APs status and updates APs status if needed.
> 
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
> b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
> index 6298571e29b2..28f8e8e133e5 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
> @@ -121,7 +121,7 @@ GetProtectedModeCS (
>    GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
>    for (Index = 0; Index < GdtEntryCount; Index++) {
>      if (GdtEntry->Bits.L == 0) {
> -      if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.L == 0) {
> +      if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.DB == 1) {
>          break;
>        }
>      }
> diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
> b/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
> index efb1bc2bf7cb..4f5a7c859a56 100644
> --- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
> +++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
> @@ -19,7 +19,7 @@ CPU_SWITCH_STATE_IDLE         equ        0
>  CPU_SWITCH_STATE_STORED       equ        1
>  CPU_SWITCH_STATE_LOADED       equ        2
> 
> -LockLocation                  equ        (RendezvousFunnelProcEnd -
> RendezvousFunnelProcStart)
> +LockLocation                  equ        (SwitchToRealProcEnd -
> RendezvousFunnelProcStart)
>  StackStartAddressLocation     equ        LockLocation + 04h
>  StackSizeLocation             equ        LockLocation + 08h
>  ApProcedureLocation           equ        LockLocation + 0Ch
> diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
> b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
> index b74046b76af3..309d53bf3b37 100644
> --- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
> +++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
> @@ -215,6 +215,16 @@ CProcedureInvoke:
>      jmp        $                 ; Never reach here
>  RendezvousFunnelProcEnd:
> 
> +;----------------------------------------------------------------------
> +---------------
> +;SwitchToRealProc procedure follows.
> +;NOT USED IN 32 BIT MODE.
> +;----------------------------------------------------------------------
> +---------------
> +global ASM_PFX(SwitchToRealProc)
> +ASM_PFX(SwitchToRealProc):
> +SwitchToRealProcStart:
> +    jmp        $                 ; Never reach here
> +SwitchToRealProcEnd:
> +
>  ;-------------------------------------------------------------------------------------
>  ;  AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
> TopOfApStack, CountTofinish);
>  ;-------------------------------------------------------------------------------------
> @@ -263,6 +273,11 @@ ASM_PFX(AsmGetAddressMap):
>      mov        dword [ebx + 0Ch], AsmRelocateApLoopStart
>      mov        dword [ebx + 10h], AsmRelocateApLoopEnd -
> AsmRelocateApLoopStart
>      mov        dword [ebx + 14h], Flat32Start - RendezvousFunnelProcStart
> +    mov        dword [ebx + 18h], SwitchToRealProcEnd -
> SwitchToRealProcStart       ; SwitchToRealSize
> +    mov        dword [ebx + 1Ch], SwitchToRealProcStart -
> RendezvousFunnelProcStart ; SwitchToRealOffset
> +    mov        dword [ebx + 20h], SwitchToRealProcStart - Flat32Start               ;
> SwitchToRealNoNxOffset
> +    mov        dword [ebx + 24h], 0                                                 ;
> SwitchToRealPM16ModeOffset
> +    mov        dword [ebx + 28h], 0                                                 ;
> SwitchToRealPM16ModeSize
> 
>      popad
>      ret
> diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
> b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
> index 58ef369342a7..c92daaaffd6b 100644
> --- a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
> +++ b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
> @@ -19,7 +19,7 @@ CPU_SWITCH_STATE_IDLE         equ        0
>  CPU_SWITCH_STATE_STORED       equ        1
>  CPU_SWITCH_STATE_LOADED       equ        2
> 
> -LockLocation                  equ        (RendezvousFunnelProcEnd -
> RendezvousFunnelProcStart)
> +LockLocation                  equ        (SwitchToRealProcEnd -
> RendezvousFunnelProcStart)
>  StackStartAddressLocation     equ        LockLocation + 08h
>  StackSizeLocation             equ        LockLocation + 10h
>  ApProcedureLocation           equ        LockLocation + 18h
> @@ -41,3 +41,5 @@ ModeTransitionSegmentLocation       equ  LockLocation +
> 98h
>  ModeHighMemoryLocation              equ  LockLocation + 9Ah
>  ModeHighSegmentLocation             equ  LockLocation + 9Eh
>  Enable5LevelPagingLocation          equ  LockLocation + 0A0h
> +SevEsIsEnabledLocation              equ  LockLocation + 0A1h
> +GhcbBaseLocation                    equ  LockLocation + 0A2h
> diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
> b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
> index 87f2523e856f..6956b408d004 100644
> --- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
> +++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
> @@ -184,9 +184,97 @@ Releaselock:
>      add        edi, StackStartAddressLocation
>      add        rax, qword [edi]
>      mov        rsp, rax
> +
> +    lea        edi, [esi + SevEsIsEnabledLocation]
> +    cmp        byte [edi], 1        ; SevEsIsEnabled
> +    jne        CProcedureInvoke
> +
> +    ;
> +    ; program GHCB
> +    ;   Each page after the GHCB is a per-CPU page, so the calculation
> programs
> +    ;   a GHCB to be every 8KB.
> +    ;
> +    mov        eax, SIZE_4KB
> +    shl        eax, 1                            ; EAX = SIZE_4K * 2
> +    mov        ecx, ebx
> +    mul        ecx                               ; EAX = SIZE_4K * 2 * CpuNumber
> +    mov        edi, esi
> +    add        edi, GhcbBaseLocation
> +    add        rax, qword [edi]
> +    mov        rdx, rax
> +    shr        rdx, 32
> +    mov        rcx, 0xc0010130
> +    wrmsr
>      jmp        CProcedureInvoke
> 
>  GetApicId:
> +    lea        edi, [esi + SevEsIsEnabledLocation]
> +    cmp        byte [edi], 1        ; SevEsIsEnabled
> +    jne        DoCpuid
> +
> +    ;
> +    ; Since we don't have a stack yet, we can't take a #VC
> +    ; exception. Use the GHCB protocol to perform the CPUID
> +    ; calls.
> +    ;
> +    mov        rcx, 0xc0010130
> +    rdmsr
> +    shl        rdx, 32
> +    or         rax, rdx
> +    mov        rdi, rax             ; RDI now holds the original GHCB GPA
> +
> +    mov        rdx, 0               ; CPUID function 0
> +    mov        rax, 0               ; RAX register requested
> +    or         rax, 4
> +    wrmsr
> +    rep vmmcall
> +    rdmsr
> +    cmp        edx, 0bh
> +    jb         NoX2ApicSevEs        ; CPUID level below
> CPUID_EXTENDED_TOPOLOGY
> +
> +    mov        rdx, 0bh             ; CPUID function 0x0b
> +    mov        rax, 040000000h      ; RBX register requested
> +    or         rax, 4
> +    wrmsr
> +    rep vmmcall
> +    rdmsr
> +    test       edx, 0ffffh
> +    jz         NoX2ApicSevEs        ; CPUID.0BH:EBX[15:0] is zero
> +
> +    mov        rdx, 0bh             ; CPUID function 0x0b
> +    mov        rax, 0c0000000h      ; RDX register requested
> +    or         rax, 4
> +    wrmsr
> +    rep vmmcall
> +    rdmsr
> +
> +    ; Processor is x2APIC capable; 32-bit x2APIC ID is now in EDX
> +    jmp        RestoreGhcb
> +
> +NoX2ApicSevEs:
> +    ; Processor is not x2APIC capable, so get 8-bit APIC ID
> +    mov        rdx, 1               ; CPUID function 1
> +    mov        rax, 040000000h      ; RBX register requested
> +    or         rax, 4
> +    wrmsr
> +    rep vmmcall
> +    rdmsr
> +    shr        edx, 24
> +
> +RestoreGhcb:
> +    mov        rbx, rdx             ; Save x2APIC/APIC ID
> +
> +    mov        rdx, rdi             ; RDI holds the saved GHCB GPA
> +    shr        rdx, 32
> +    mov        eax, edi
> +    wrmsr
> +
> +    mov        rdx, rbx
> +
> +    ; x2APIC ID or APIC ID is in EDX
> +    jmp        GetProcessorNumber
> +
> +DoCpuid:
>      mov        eax, 0
>      cpuid
>      cmp        eax, 0bh
> @@ -253,12 +341,158 @@ CProcedureInvoke:
> 
>  RendezvousFunnelProcEnd:
> 
> +;----------------------------------------------------------------------
> +---------------
> +;SwitchToRealProc procedure follows.
> +;ALSO THIS PROCEDURE IS EXECUTED BY APs TRANSITIONING TO 16 BIT
> MODE.
> +HENCE THIS PROC ;IS IN MACHINE CODE.
> +;  SwitchToRealProc (UINTN BufferStart, UINT16 Code16, UINT16 Code32,
> +UINTN StackStart) ;  rcx - Buffer Start ;  rdx - Code16 Selector Offset
> +;  r8  - Code32 Selector Offset ;  r9  - Stack Start
> +;----------------------------------------------------------------------
> +---------------
> +global ASM_PFX(SwitchToRealProc)
> +ASM_PFX(SwitchToRealProc):
> +SwitchToRealProcStart:
> +BITS 64
> +    cli
> +
> +    ;
> +    ; Get RDX reset value before changing stacks since the
> +    ; new stack won't be able to accomodate a #VC exception.
> +    ;
> +    push       rax
> +    push       rbx
> +    push       rcx
> +    push       rdx
> +
> +    mov        rax, 1
> +    cpuid
> +    mov        rsi, rax                    ; Save off the reset value for RDX
> +
> +    pop        rdx
> +    pop        rcx
> +    pop        rbx
> +    pop        rax
> +
> +    ;
> +    ; Establish stack below 1MB
> +    ;
> +    mov        rsp, r9
> +
> +    ;
> +    ; Push ultimate Reset Vector onto the stack
> +    ;
> +    mov        rax, rcx
> +    shr        rax, 4
> +    push       word 0x0002                 ; RFLAGS
> +    push       ax                          ; CS
> +    push       word 0x0000                 ; RIP
> +    push       word 0x0000                 ; For alignment, will be discarded
> +
> +    ;
> +    ; Get address of "16-bit operand size" label
> +    ;
> +    lea        rbx, [PM16Mode]
> +
> +    ;
> +    ; Push addresses used to change to compatibility mode
> +    ;
> +    lea        rax, [CompatMode]
> +    push       r8
> +    push       rax
> +
> +    ;
> +    ; Clear R8 - R15, for reset, before going into 32-bit mode
> +    ;
> +    xor        r8, r8
> +    xor        r9, r9
> +    xor        r10, r10
> +    xor        r11, r11
> +    xor        r12, r12
> +    xor        r13, r13
> +    xor        r14, r14
> +    xor        r15, r15
> +
> +    ;
> +    ; Far return into 32-bit mode
> +    ;
> +o64 retf
> +
> +BITS 32
> +CompatMode:
> +    ;
> +    ; Set up stack to prepare for exiting protected mode
> +    ;
> +    push       edx                         ; Code16 CS
> +    push       ebx                         ; PM16Mode label address
> +
> +    ;
> +    ; Disable paging
> +    ;
> +    mov        eax, cr0                    ; Read CR0
> +    btr        eax, 31                     ; Set PG=0
> +    mov        cr0, eax                    ; Write CR0
> +
> +    ;
> +    ; Disable long mode
> +    ;
> +    mov        ecx, 0c0000080h             ; EFER MSR number
> +    rdmsr                                  ; Read EFER
> +    btr        eax, 8                      ; Set LME=0
> +    wrmsr                                  ; Write EFER
> +
> +    ;
> +    ; Disable PAE
> +    ;
> +    mov        eax, cr4                    ; Read CR4
> +    btr        eax, 5                      ; Set PAE=0
> +    mov        cr4, eax                    ; Write CR4
> +
> +    mov        edx, esi                    ; Restore RDX reset value
> +
> +    ;
> +    ; Switch to 16-bit operand size
> +    ;
> +    retf
> +
> +BITS 16
> +    ;
> +    ; At entry to this label
> +    ;   - RDX will have its reset value
> +    ;   - On the top of the stack
> +    ;     - Alignment data (two bytes) to be discarded
> +    ;     - IP for Real Mode (two bytes)
> +    ;     - CS for Real Mode (two bytes)
> +    ;
> +PM16Mode:
> +    mov        eax, cr0                    ; Read CR0
> +    btr        eax, 0                      ; Set PE=0
> +    mov        cr0, eax                    ; Write CR0
> +
> +    pop        ax                          ; Discard alignment data
> +
> +    ;
> +    ; Clear registers (except RDX and RSP) before going into 16-bit mode
> +    ;
> +    xor        eax, eax
> +    xor        ebx, ebx
> +    xor        ecx, ecx
> +    xor        esi, esi
> +    xor        edi, edi
> +    xor        ebp, ebp
> +
> +    iret
> +
> +SwitchToRealProcEnd:
> +
>  ;-------------------------------------------------------------------------------------
>  ;  AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
> TopOfApStack, CountTofinish);
>  ;-------------------------------------------------------------------------------------
>  global ASM_PFX(AsmRelocateApLoop)
>  ASM_PFX(AsmRelocateApLoop):
>  AsmRelocateApLoopStart:
> +BITS 64
>      cli                          ; Disable interrupt before switching to 32-bit mode
>      mov        rax, [rsp + 40]   ; CountTofinish
>      lock dec   dword [rax]       ; (*CountTofinish)--
> @@ -324,6 +558,11 @@ ASM_PFX(AsmGetAddressMap):
>      mov        qword [rcx + 18h], rax
>      mov        qword [rcx + 20h], AsmRelocateApLoopEnd -
> AsmRelocateApLoopStart
>      mov        qword [rcx + 28h], Flat32Start - RendezvousFunnelProcStart
> +    mov        qword [rcx + 30h], SwitchToRealProcEnd -
> SwitchToRealProcStart          ; SwitchToRealSize
> +    mov        qword [rcx + 38h], SwitchToRealProcStart -
> RendezvousFunnelProcStart    ; SwitchToRealOffset
> +    mov        qword [rcx + 40h], SwitchToRealProcStart - Flat32Start                  ;
> SwitchToRealNoNxOffset
> +    mov        qword [rcx + 48h], PM16Mode -
> RendezvousFunnelProcStart                 ; SwitchToRealPM16ModeOffset
> +    mov        qword [rcx + 50h], SwitchToRealProcEnd - PM16Mode                       ;
> SwitchToRealPM16ModeSize
>      ret
> 
>  ;-------------------------------------------------------------------------------------
> --
> 2.27.0


  reply	other threads:[~2020-07-15  5:23 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14 14:27 [PATCH v10 00/46] SEV-ES guest support Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 01/46] MdeModulePkg: Create PCDs to be used in support of SEV-ES Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 02/46] UefiCpuPkg: Create PCD " Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 03/46] MdePkg: Add the MSR definition for the GHCB register Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 04/46] MdePkg: Add a structure definition for the GHCB Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 05/46] MdeModulePkg/DxeIplPeim: Support GHCB pages when creating page tables Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 06/46] MdePkg/BaseLib: Add support for the XGETBV instruction Lendacky, Thomas
2020-07-15 15:55   ` [edk2-devel] " Laszlo Ersek
2020-07-15 16:17     ` Lendacky, Thomas
2020-07-17 15:46       ` Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 07/46] MdePkg/BaseLib: Add support for the VMGEXIT instruction Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 08/46] UefiCpuPkg: Implement library support for VMGEXIT Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 09/46] OvmfPkg: Prepare OvmfPkg to use the VmgExitLib library Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 10/46] UefiPayloadPkg: Prepare UefiPayloadPkg " Lendacky, Thomas
2020-07-20 15:27   ` [edk2-devel] " Ma, Maurice
2020-07-14 14:27 ` [PATCH v10 11/46] UefiCpuPkg/CpuExceptionHandler: Add base support for the #VC exception Lendacky, Thomas
2020-07-14 14:27 ` [PATCH v10 12/46] OvmfPkg/VmgExitLib: Implement library support for VmgExitLib in OVMF Lendacky, Thomas
2020-07-15 16:06   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 13/46] OvmfPkg/VmgExitLib: Add support for IOIO_PROT NAE events Lendacky, Thomas
2020-07-15 16:08   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 14/46] OvmfPkg/VmgExitLib: Support string IO " Lendacky, Thomas
2020-07-15 16:09   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 15/46] OvmfPkg/VmgExitLib: Add support for CPUID " Lendacky, Thomas
2020-07-15 16:10   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 16/46] OvmfPkg/VmgExitLib: Add support for MSR_PROT " Lendacky, Thomas
2020-07-15 16:11   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 17/46] OvmfPkg/VmgExitLib: Add support for NPF NAE events (MMIO) Lendacky, Thomas
2020-07-15 16:19   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 18/46] OvmfPkg/VmgExitLib: Add support for WBINVD NAE events Lendacky, Thomas
2020-07-15 16:21   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 19/46] OvmfPkg/VmgExitLib: Add support for RDTSC " Lendacky, Thomas
2020-07-15 16:21   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 20/46] OvmfPkg/VmgExitLib: Add support for RDPMC " Lendacky, Thomas
2020-07-15 16:21   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 21/46] OvmfPkg/VmgExitLib: Add support for INVD " Lendacky, Thomas
2020-07-15 16:21   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 22/46] OvmfPkg/VmgExitLib: Add support for VMMCALL " Lendacky, Thomas
2020-07-15 16:21   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 23/46] OvmfPkg/VmgExitLib: Add support for RDTSCP " Lendacky, Thomas
2020-07-15 16:21   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:27 ` [PATCH v10 24/46] OvmfPkg/VmgExitLib: Add support for MONITOR/MONITORX " Lendacky, Thomas
2020-07-15 16:21   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:37 ` [PATCH v10 25/46] OvmfPkg/VmgExitLib: Add support for MWAIT/MWAITX " Lendacky, Thomas
2020-07-15 16:22   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:37 ` [PATCH v10 26/46] OvmfPkg/VmgExitLib: Add support for DR7 Read/Write " Lendacky, Thomas
2020-07-15 16:25   ` [edk2-devel] " Laszlo Ersek
2020-07-14 14:37 ` [PATCH v10 27/46] OvmfPkg/MemEncryptSevLib: Add an SEV-ES guest indicator function Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 28/46] OvmfPkg: Add support to perform SEV-ES initialization Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 29/46] OvmfPkg: Create a GHCB page for use during Sec phase Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 30/46] OvmfPkg/PlatformPei: Reserve GHCB-related areas if S3 is supported Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 31/46] OvmfPkg: Create GHCB pages for use during Pei and Dxe phase Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 32/46] OvmfPkg/PlatformPei: Move early GDT into ram when SEV-ES is enabled Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 33/46] UefiCpuPkg: Create an SEV-ES workarea PCD Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 34/46] OvmfPkg: Reserve a page in memory for the SEV-ES usage Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 35/46] OvmfPkg/PlatformPei: Reserve SEV-ES work area if S3 is supported Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 36/46] OvmfPkg/ResetVector: Add support for a 32-bit SEV check Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 37/46] OvmfPkg/Sec: Add #VC exception handling for Sec phase Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 38/46] OvmfPkg/Sec: Enable cache early to speed up booting Lendacky, Thomas
2020-07-14 14:37 ` [PATCH v10 39/46] OvmfPkg/QemuFlashFvbServicesRuntimeDxe: Bypass flash detection with SEV-ES Lendacky, Thomas
2020-07-14 19:50 ` [PATCH v10 40/46] UefiCpuPkg: Add a 16-bit protected mode code segment descriptor Lendacky, Thomas
2020-07-14 19:50 ` [PATCH v10 41/46] UefiCpuPkg/MpInitLib: Add CPU MP data flag to indicate if SEV-ES is enabled Lendacky, Thomas
2020-07-14 19:50 ` [PATCH v10 42/46] UefiCpuPkg: Allow AP booting under SEV-ES Lendacky, Thomas
2020-07-15  5:23   ` Dong, Eric [this message]
2020-07-14 19:50 ` [PATCH v10 43/46] OvmfPkg: Use the SEV-ES work area for the SEV-ES AP reset vector Lendacky, Thomas
2020-07-14 19:50 ` [PATCH v10 44/46] OvmfPkg: Move the GHCB allocations into reserved memory Lendacky, Thomas
2020-07-14 19:50 ` [PATCH v10 45/46] UefiCpuPkg/MpInitLib: Prepare SEV-ES guest APs for OS use Lendacky, Thomas
2020-07-15  5:55   ` Dong, Eric
2020-07-14 19:50 ` [PATCH v10 46/46] Maintainers.txt: Add reviewers for the OvmfPkg SEV-related files Lendacky, Thomas
2020-07-15 16:31   ` [edk2-devel] " Laszlo Ersek

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