Laszlo: > -----Original Message----- > From: Laszlo Ersek <ler...@redhat.com> > Sent: Tuesday, July 28, 2020 8:04 PM > To: Gao, Liming <liming....@intel.com>; Tom Lendacky > <thomas.lenda...@amd.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>; 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 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. > > > > 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. > Yes. I also realize nasm version impact. It may also impact Mac OS. We should try to avoid new requirement to update nasm version.
Thanks Liming > I seem to recall that it was me to recommend "BITS 64" in front of "rep > vmmcall" in the IA32 NASM source file: > > https://edk2.groups.io/g/devel/message/48292 > http://mid.mail-archive.com/e8a8e21e-4045-1b2b-f959-13fbe00132d9@redhat.com > > 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. :( > > 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? > > 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(). > > 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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