On 7/28/20 7:04 AM, Laszlo Ersek wrote: > On 07/28/20 09:39, Gao, Liming wrote: >> This error is reported from nasm compiler. My nasm compiler version is >> 2.11.08. It may be a little old. 2.12 should be fine.
I have 2.13.02. >> >> This change also requires to update >> edk2\BaseTools\Conf\tools_def.template and mention nasm compiler >> version. > > "tools_def.template" says: > > NASM 2.10 or later for use with the GCC toolchain family > > Bumping the NASM requirement from 2.10 to 2.12 will rule out: > > - Debian "jessie" (oldoldstable), > - Ubuntu "xenial" (16.04 LTS), > - and RHEL7, > > as build hosts. > > Debian "jessie" is no longer supported (LTS ended in June 2020), but > Ubuntu "xenial" and RHEL7 are still supported by their vendors. > > I seem to recall that it was me to recommend "BITS 64" in front of "rep > vmmcall" in the IA32 NASM source file: > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fedk2.groups.io%2Fg%2Fdevel%2Fmessage%2F48292&data=02%7C01%7Cthomas.lendacky%40amd.com%7Ca8b0f66286b745e78b1d08d832ee6f95%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637315346944536242&sdata=4DBhHd2WYgoEx%2F76YaNRalJlSvd0rAIWxrN1qOFR9Tw%3D&reserved=0 > > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmid.mail-archive.com%2Fe8a8e21e-4045-1b2b-f959-13fbe00132d9%40redhat.com&data=02%7C01%7Cthomas.lendacky%40amd.com%7Ca8b0f66286b745e78b1d08d832ee6f95%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637315346944536242&sdata=AV5lDCYWOm2cTOzlaI7OwMjcK9TknVGBNFAkNJhahuM%3D&reserved=0 > > I don't understand why my testing worked back then, and now it doesn't. > (IOW, I can also reproduce the error that Liming reported!) It's likely > because I didn't specify the elf32 output format back then. > > Indeed: the following command fails: > >> "nasm" \ >> -I"$WORKSPACE"/MdePkg/Library/BaseLib/Ia32/ \ >> -I"$WORKSPACE"/MdePkg/Library/BaseLib/Ia32/ \ >> -I"$WORKSPACE"/MdePkg/Library/BaseLib/ \ >> >> -I"$WORKSPACE"/Build/OvmfIa32/NOOPT_GCC48/IA32/MdePkg/Library/BaseLib/BaseLib/DEBUG/ >> \ >> -I"$WORKSPACE"/MdePkg/ \ >> -I"$WORKSPACE"/MdePkg/Include/ \ >> -I"$WORKSPACE"/MdePkg/Test/UnitTest/Include/ \ >> -I"$WORKSPACE"/MdePkg/Include/Ia32/ \ >> -f elf32 \ >> -o >> "$WORKSPACE"/Build/OvmfIa32/NOOPT_GCC48/IA32/MdePkg/Library/BaseLib/BaseLib/OUTPUT/Ia32/VmgExit.obj >> \ >> >> "$WORKSPACE"/Build/OvmfIa32/NOOPT_GCC48/IA32/MdePkg/Library/BaseLib/BaseLib/OUTPUT/Ia32/VmgExit.iii > > but if I remove "-f elf32", it completes fine. :( With version 2.13.02, I can successfully build with '-f elf32', so it seems to be version related. > > The AMD manual says about VMGEXIT: > >> The VMGEXIT opcode is only valid within a guest when run with SEV-ES >> mode active. If the guest is not run with SEV-ES mode active, the >> VMGEXIT opcode will be treated as a VMMCALL opcode and will behave >> exactly like a VMMCALL. > > VMGEXIT is a SEV-ES-only form of guest-host communication. SEV-ES mode > depends on SEV. A SEV guest can only interact with the host (= decrypt > its pages for the host to access) if the guest is executing in long > mode. > > So does it even make sense to *attempt* implementing AsmVmgExit() > "correctly" for IA32? We are only enabling SEV-ES support for X64, so this is a valid point. It would be very hard to enable the Ia32X64 combination (because of how long it takes to get into long mode) and impossible for the Ia32 alone. > > I don't want to complicate the build dependencies in this series > further, so I won't suggest that we simply *not* implement AsmVmgExit() > for IA32 at all. (Purely from a BaseLib perspective, this would be a > valid approach, but then call sites would have to be *build-time* > restricted to X64 too. The call sites *are* already restricted to X64, > AIUI, but that happens at runtime (= dynamic checks), not at build > time.) > > So here's what I suggest: implement AsmVmgExit() for IA32 in the C > language, namely as a call to CpuBreakpoint(). IIUC, create a VmgExit.c file in MdePkg/Library/BaseLib/Ia32/ that doesn't actually encode the VMGEXIT instruction, just calls CpuBreakpoint(), e.g.: VOID EFIAPI AsmVmgExit ( VOID ) { CpuBreakpoint(); } The other alternative is to use a DB-encoded instruction, though I know that isn't the most popular approach. The BITS 64 method to generate the instruction bytes is also used in OvmfPkg/ResetVector/Ia32/PageTables64.asm, but that file is only included when ARCH_X64 is defined, so there shouldn't be an issue there, plus the nasm file format is bin (-f bin). Thanks, Tom > > I wouldn't like to tighten the NASM version requirement for *all* of > edk2, for the sake of building a BaseLib primitive for IA32 that we > never *call* on IA32. > > Thanks, > Laszlo > >> >> Thanks >> Liming >> -----Original Message----- >> From: Tom Lendacky <thomas.lenda...@amd.com> >> Sent: 2020t728å 12:08 >> To: Gao, Liming <liming....@intel.com>; devel@edk2.groups.io >> Cc: Brijesh Singh <brijesh.si...@amd.com>; Ard Biesheuvel >> <ard.biesheu...@arm.com>; Dong, Eric <eric.d...@intel.com>; Justen, Jordan L >> <jordan.l.jus...@intel.com>; Laszlo Ersek <ler...@redhat.com>; Kinney, >> Michael D <michael.d.kin...@intel.com>; Ni, Ray <ray...@intel.com> >> Subject: Re: [PATCH v12 07/46] MdePkg/BaseLib: Add support for the VMGEXIT >> instruction >> >> On 7/27/20 8:34 PM, Gao, Liming wrote: >>> Tom: >> >> Hi Liming, >> >>> I meet with GCC failure on this patch. Can you help check it? If nasm >>> doesn't support the vmmcall instruction in 32-bit mode, you have to use >>> inline assembly to support it. >> >> What version of GCC are you using. I was able to successfully build the >> Ia32 version with my GCC level. The Ia32 version uses a trick to do switch >> to 64-bit just to encode the instruction. Looks like that doesn't work with >> your version of GCC. >> >> I can probably switch to defining the instruction as bytes. Let me look into >> that and possibly send you a patch to test. >> >> Thanks, >> Tom >> >>> >>> Edk2/Build/IntelFsp2Pkg/DEBUG_GCC5/IA32/MdePkg/Library/BaseLib/BaseLib >>> /OUTPUT/Ia32/VmgExit.iii:33: error: elf32 output format does not >>> support 64-bit code >>> GNUmakefile:741: recipe for target >>> >>> Thanks >>> Liming >>> -----Original Message----- >>> From: Tom Lendacky <thomas.lenda...@amd.com> >>> Sent: 2020t727å 23:26 >>> To: devel@edk2.groups.io >>> Cc: Brijesh Singh <brijesh.si...@amd.com>; Ard Biesheuvel >>> <ard.biesheu...@arm.com>; Dong, Eric <eric.d...@intel.com>; Justen, >>> Jordan L <jordan.l.jus...@intel.com>; Laszlo Ersek >>> <ler...@redhat.com>; Gao, Liming <liming....@intel.com>; Kinney, >>> Michael D <michael.d.kin...@intel.com>; Ni, Ray <ray...@intel.com> >>> Subject: [PATCH v12 07/46] MdePkg/BaseLib: Add support for the VMGEXIT >>> instruction >>> >>> From: Tom Lendacky <thomas.lenda...@amd.com> >>> >>> BZ: >>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugz >>> illa.tianocore.org%2Fshow_bug.cgi%3Fid%3D2198&data=02%7C01%7Cthoma >>> s.lendacky%40amd.com%7C77c8250cd9e14f2929a008d832965726%7C3dd8961fe488 >>> 4e608e11a82d994e183d%7C0%7C0%7C637314968570901400&sdata=6zqseI3tVm >>> aw351w9mfEymMnDcjDzjvcBrhARU6r3Ho%3D&reserved=0 >>> >>> 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. >>> >>> Provide the necessary support to execute the VMGEXIT instruction, which is >>> "rep; vmmcall". >>> >>> Cc: Michael D Kinney <michael.d.kin...@intel.com> >>> Cc: Liming Gao <liming....@intel.com> >>> Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com> >>> --- >>> MdePkg/Library/BaseLib/BaseLib.inf | 2 ++ >>> MdePkg/Include/Library/BaseLib.h | 14 +++++++++ >>> MdePkg/Library/BaseLib/Ia32/VmgExit.nasm | 37 ++++++++++++++++++++++++ >>> MdePkg/Library/BaseLib/X64/VmgExit.nasm | 32 ++++++++++++++++++++ >>> 4 files changed, 85 insertions(+) >>> create mode 100644 MdePkg/Library/BaseLib/Ia32/VmgExit.nasm >>> create mode 100644 MdePkg/Library/BaseLib/X64/VmgExit.nasm >>> >>> diff --git a/MdePkg/Library/BaseLib/BaseLib.inf >>> b/MdePkg/Library/BaseLib/BaseLib.inf >>> index 3b93b5db8d24..3b85c56c3c03 100644 >>> --- a/MdePkg/Library/BaseLib/BaseLib.inf >>> +++ b/MdePkg/Library/BaseLib/BaseLib.inf >>> @@ -184,6 +184,7 @@ [Sources.Ia32] >>> Ia32/DisableCache.nasm| GCC >>> Ia32/RdRand.nasm >>> Ia32/XGetBv.nasm >>> + Ia32/VmgExit.nasm >>> >>> Ia32/DivS64x64Remainder.c >>> Ia32/InternalSwitchStack.c | MSFT >>> @@ -317,6 +318,7 @@ [Sources.X64] >>> X64/DisablePaging64.nasm >>> X64/RdRand.nasm >>> X64/XGetBv.nasm >>> + X64/VmgExit.nasm >>> ChkStkGcc.c | GCC >>> >>> [Sources.EBC] >>> diff --git a/MdePkg/Include/Library/BaseLib.h >>> b/MdePkg/Include/Library/BaseLib.h >>> index 7edf0051a0a0..04fb329eaabb 100644 >>> --- a/MdePkg/Include/Library/BaseLib.h >>> +++ b/MdePkg/Include/Library/BaseLib.h >>> @@ -7848,6 +7848,20 @@ AsmXGetBv ( >>> ); >>> >>> >>> +/** >>> + 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/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm >>> b/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm >>> new file mode 100644 >>> index 000000000000..a4b37385cc7a >>> --- /dev/null >>> +++ b/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm >>> @@ -0,0 +1,37 @@ >>> +;-------------------------------------------------------------------- >>> +-- >>> +-------- >>> +; >>> +; Copyright (C) 2020, Advanced Micro Devices, Inc. All rights >>> +reserved.<BR> ; SPDX-License-Identifier: BSD-2-Clause-Patent ; ; >>> +Module >>> +Name: >>> +; >>> +; VmgExit.Asm >>> +; >>> +; Abstract: >>> +; >>> +; AsmVmgExit function >>> +; >>> +; Notes: >>> +; >>> +;-------------------------------------------------------------------- >>> +-- >>> +-------- >>> + >>> + SECTION .text >>> + >>> +;-------------------------------------------------------------------- >>> +-- >>> +-------- >>> +; VOID >>> +; EFIAPI >>> +; AsmVmgExit ( >>> +; VOID >>> +; ); >>> +;-------------------------------------------------------------------- >>> +-- >>> +-------- >>> +global ASM_PFX(AsmVmgExit) >>> +ASM_PFX(AsmVmgExit): >>> +; >>> +; NASM doesn't support the vmmcall instruction in 32-bit mode, so >>> +work around ; this by temporarily switching to 64-bit mode. >>> +; >>> +BITS 64 >>> + rep vmmcall >>> +BITS 32 >>> + ret >>> + >>> diff --git a/MdePkg/Library/BaseLib/X64/VmgExit.nasm >>> b/MdePkg/Library/BaseLib/X64/VmgExit.nasm >>> new file mode 100644 >>> index 000000000000..26f034593c67 >>> --- /dev/null >>> +++ b/MdePkg/Library/BaseLib/X64/VmgExit.nasm >>> @@ -0,0 +1,32 @@ >>> +;-------------------------------------------------------------------- >>> +-- >>> +-------- >>> +; >>> +; Copyright (C) 2020, Advanced Micro Devices, Inc. All rights >>> +reserved.<BR> ; SPDX-License-Identifier: BSD-2-Clause-Patent ; ; >>> +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 >>> + >>> -- >>> 2.27.0 >>> >> > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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