[edk2-devel] [RFC PATCH 08/28] MdePkg/BaseLib: Implement the VMGEXIT support
Ni, Ray
ray.ni at intel.com
Mon Aug 19 21:47:42 UTC 2019
Tom,
1. It's not a common practice to have static inline functions defined in header file. Who is going to call them?
2. Recently I made a change to move the AMD registers definitions to MdePkg/Include/Register/Amd from UefiCpuPkg. Do you think that's a good idea and can you please put your new register definitions to MdePkg as well?
3. What happens if the "rep; vmmcall" is executed in Intel processor?
Thanks,
Ray
> -----Original Message-----
> From: Lendacky, Thomas <Thomas.Lendacky at amd.com>
> Sent: Monday, August 19, 2019 2:36 PM
> To: devel at edk2.groups.io
> Cc: Justen, Jordan L <jordan.l.justen at intel.com>; Laszlo Ersek <lersek at redhat.com>; Ard Biesheuvel
> <ard.biesheuvel at linaro.org>; Kinney, Michael D <michael.d.kinney at intel.com>; Gao, Liming <liming.gao at intel.com>; Dong,
> Eric <eric.dong at intel.com>; Ni, Ray <ray.ni at intel.com>; Singh, Brijesh <brijesh.singh at amd.com>
> Subject: [RFC PATCH 08/28] MdePkg/BaseLib: Implement the VMGEXIT support
>
> From: Tom Lendacky <thomas.lendacky at amd.com>
>
> VMGEXIT is a new instruction used for Hypervisor/Guest communication when
> running as an SEV-ES guest. A VMGEXIT will cause an automatic exit (AE)
> to occur, resulting in a #VMEXIT with an exit code value of 0x403.
>
> To support VMGEXIT, define the VMGEXIT assember routine to issue the
> instruction (rep; vmmcall), the GHCB structure and some helper functions
> for communicating register information to and from the hypervisor and the
> guest.
>
> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
> ---
> MdePkg/Library/BaseLib/BaseLib.inf | 1 +
> MdePkg/Include/Library/BaseLib.h | 14 ++
> UefiCpuPkg/Include/Register/Amd/Ghcb.h | 197 ++++++++++++++++++++++++
> MdePkg/Library/BaseLib/X64/GccInline.c | 17 ++
> MdePkg/Library/BaseLib/X64/VmgExit.nasm | 38 +++++
> 5 files changed, 267 insertions(+)
> create mode 100644 UefiCpuPkg/Include/Register/Amd/Ghcb.h
> create mode 100644 MdePkg/Library/BaseLib/X64/VmgExit.nasm
>
> diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf
> index 3586beb0ab5c..a41401340f95 100644
> --- a/MdePkg/Library/BaseLib/BaseLib.inf
> +++ b/MdePkg/Library/BaseLib/BaseLib.inf
> @@ -286,6 +286,7 @@ [Sources.X64]
> X64/ReadCr2.nasm| MSFT
> X64/ReadCr0.nasm| MSFT
> X64/ReadEflags.nasm| MSFT
> + X64/VmgExit.nasm | MSFT
>
>
> X64/Non-existing.c
> diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
> index 2a75bc023f56..80bd5cf57a72 100644
> --- a/MdePkg/Include/Library/BaseLib.h
> +++ b/MdePkg/Include/Library/BaseLib.h
> @@ -7880,6 +7880,20 @@ AsmLfence (
> VOID
> );
>
> +/**
> + Executes a VMGEXIT instruction (VMMCALL with a REP prefix)
> +
> + Executes a VMGEXIT instruction. This function is only available on IA-32 and
> + x64.
> +
> +**/
> +VOID
> +EFIAPI
> +AsmVmgExit (
> + VOID
> + );
> +
> +
> /**
> Patch the immediate operand of an IA32 or X64 instruction such that the byte,
> word, dword or qword operand is encoded at the end of the instruction's
> diff --git a/UefiCpuPkg/Include/Register/Amd/Ghcb.h b/UefiCpuPkg/Include/Register/Amd/Ghcb.h
> new file mode 100644
> index 000000000000..e9fd116fac25
> --- /dev/null
> +++ b/UefiCpuPkg/Include/Register/Amd/Ghcb.h
> @@ -0,0 +1,197 @@
> +
> +#ifndef __GHCB_H__
> +#define __GHCB_H__
> +
> +#include <Protocol/DebugSupport.h>
> +#include <Library/BaseLib.h>
> +#include <Library/DebugLib.h>
> +
> +#define UD_EXCEPTION 6
> +#define GP_EXCEPTION 13
> +
> +#define GHCB_VERSION_MIN 1
> +#define GHCB_VERSION_MAX 1
> +
> +#define GHCB_STANDARD_USAGE 0
> +
> +typedef enum {
> + SvmExitDr7Read = 0x27,
> + SvmExitDr7Write = 0x37,
> + SvmExitRdtsc = 0x6E,
> + SvmExitRdpmc,
> + SvmExitCpuid = 0x72,
> + SvmExitInvd = 0x76,
> + SvmExitIoioProt = 0x7B,
> + SvmExitMsr,
> + SvmExitVmmCall = 0x81,
> + SvmExitRdtscp = 0x87,
> + SvmExitWbinvd = 0x89,
> + SvmExitMonitor,
> + SvmExitMwait,
> + SvmExitNpf = 0x400,
> +
> + // VMG special exits
> + SvmExitMmioRead = 0x80000001,
> + SvmExitMmioWrite,
> + SvmExitNmiComplete,
> + SvmExitApResetHold,
> +
> + SvmExitUnsupported = 0x8000FFFF,
> +} SVM_EXITCODE;
> +
> +typedef enum {
> + GhcbCpl = 25,
> + GhcbRflags = 46,
> + GhcbRip,
> + GhcbRsp = 59,
> + GhcbRax = 63,
> + GhcbRcx = 97,
> + GhcbRdx,
> + GhcbRbx,
> + GhcbRbp = 101,
> + GhcbRsi,
> + GhcbRdi,
> + GhcbR8,
> + GhcbR9,
> + GhcbR10,
> + GhcbR11,
> + GhcbR12,
> + GhcbR13,
> + GhcbR14,
> + GhcbR15,
> + GhcbXCr0 = 125,
> +} GHCB_REGISTER;
> +
> +typedef struct {
> + UINT8 Reserved1[203];
> + UINT8 Cpl;
> + UINT8 Reserved2[148];
> + UINT64 Dr7;
> + UINT8 Reserved3[144];
> + UINT64 Rax;
> + UINT8 Reserved4[264];
> + UINT64 Rcx;
> + UINT64 Rdx;
> + UINT64 Rbx;
> + UINT8 Reserved5[112];
> + UINT64 SwExitCode;
> + UINT64 SwExitInfo1;
> + UINT64 SwExitInfo2;
> + UINT64 SwScratch;
> + UINT8 Reserved6[56];
> + UINT64 XCr0;
> + UINT8 ValidBitmap[16];
> + UINT64 X87StateGpa;
> + UINT8 Reserved7[1016];
> +} __attribute__ ((__packed__)) GHCB_SAVE_AREA;
> +
> +typedef struct {
> + GHCB_SAVE_AREA SaveArea;
> + UINT8 SharedBuffer[2032];
> + UINT8 Reserved1[10];
> + UINT16 ProtocolVersion;
> + UINT32 GhcbUsage;
> +} __attribute__ ((__packed__)) __attribute__ ((aligned(SIZE_4KB))) GHCB;
> +
> +typedef union {
> + struct {
> + UINT32 Lower32Bits;
> + UINT32 Upper32Bits;
> + } Elements;
> +
> + UINT64 Uint64;
> +} GHCB_EXIT_INFO;
> +
> +static inline
> +BOOLEAN
> +GhcbIsRegValid(
> + GHCB *Ghcb,
> + GHCB_REGISTER Reg
> + )
> +{
> + UINT32 RegIndex = Reg / 8;
> + UINT32 RegBit = Reg & 0x07;
> +
> + return (Ghcb->SaveArea.ValidBitmap[RegIndex] & (1 << RegBit));
> +}
> +
> +static inline
> +VOID
> +GhcbSetRegValid(
> + GHCB *Ghcb,
> + GHCB_REGISTER Reg
> + )
> +{
> + UINT32 RegIndex = Reg / 8;
> + UINT32 RegBit = Reg & 0x07;
> +
> + Ghcb->SaveArea.ValidBitmap[RegIndex] |= (1 << RegBit);
> +}
> +
> +static inline
> +VOID
> +VmgException(
> + UINTN Exception
> + )
> +{
> + switch (Exception) {
> + case UD_EXCEPTION:
> + case GP_EXCEPTION:
> + break;
> + default:
> + ASSERT (0);
> + }
> +}
> +
> +static inline
> +UINTN
> +VmgExit(
> + GHCB *Ghcb,
> + UINT64 ExitCode,
> + UINT64 ExitInfo1,
> + UINT64 ExitInfo2
> + )
> +{
> + GHCB_EXIT_INFO ExitInfo;
> + UINTN Reason, Action;
> +
> + Ghcb->SaveArea.SwExitCode = ExitCode;
> + Ghcb->SaveArea.SwExitInfo1 = ExitInfo1;
> + Ghcb->SaveArea.SwExitInfo2 = ExitInfo2;
> + AsmVmgExit ();
> +
> + if (!Ghcb->SaveArea.SwExitInfo1) {
> + return 0;
> + }
> +
> + ExitInfo.Uint64 = Ghcb->SaveArea.SwExitInfo1;
> + Reason = ExitInfo.Elements.Upper32Bits;
> + Action = ExitInfo.Elements.Lower32Bits;
> + switch (Action) {
> + case 1:
> + VmgException (Reason);
> + break;
> + default:
> + ASSERT (0);
> + }
> +
> + return Reason;
> +}
> +
> +static inline
> +VOID
> +VmgInit(
> + GHCB *Ghcb
> + )
> +{
> + SetMem (&Ghcb->SaveArea, sizeof (Ghcb->SaveArea), 0);
> +}
> +
> +static inline
> +VOID
> +VmgDone(
> + GHCB *Ghcb
> + )
> +{
> +}
> +#endif
> diff --git a/MdePkg/Library/BaseLib/X64/GccInline.c b/MdePkg/Library/BaseLib/X64/GccInline.c
> index 154ce1f57e92..17539caa0798 100644
> --- a/MdePkg/Library/BaseLib/X64/GccInline.c
> +++ b/MdePkg/Library/BaseLib/X64/GccInline.c
> @@ -1798,3 +1798,20 @@ AsmFlushCacheLine (
> }
>
>
> +/**
> + Executes a VMGEXIT instruction.
> +
> + Executes a VMGEXIT instruction. This function is only available on IA-32 and
> + X64.
> +
> +**/
> +VOID
> +EFIAPI
> +AsmVmgExit (
> + VOID
> + )
> +{
> + __asm__ __volatile__ ("rep; vmmcall":::"memory");
> +}
> +
> +
> diff --git a/MdePkg/Library/BaseLib/X64/VmgExit.nasm b/MdePkg/Library/BaseLib/X64/VmgExit.nasm
> new file mode 100644
> index 000000000000..b673bb94b60d
> --- /dev/null
> +++ b/MdePkg/Library/BaseLib/X64/VmgExit.nasm
> @@ -0,0 +1,38 @@
> +;------------------------------------------------------------------------------
> +;
> +; Copyright (c) 2019, Advanced Micro Device, Inc. All rights reserved.<BR>
> +; This program and the accompanying materials
> +; are licensed and made available under the terms and conditions of the BSD License
> +; which accompanies this distribution. The full text of the license may be found at
> +; http://opensource.org/licenses/bsd-license.php.
> +;
> +; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +;
> +; Module Name:
> +;
> +; VmgExit.Asm
> +;
> +; Abstract:
> +;
> +; AsmVmgExit function
> +;
> +; Notes:
> +;
> +;------------------------------------------------------------------------------
> +
> + DEFAULT REL
> + SECTION .text
> +
> +;------------------------------------------------------------------------------
> +; VOID
> +; EFIAPI
> +; AsmVmgExit (
> +; VOID
> +; );
> +;------------------------------------------------------------------------------
> +global ASM_PFX(AsmVmgExit)
> +ASM_PFX(AsmVmgExit):
> + rep; vmmcall
> + ret
> +
> --
> 2.17.1
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