Hi Tom, On 06/05/20 15:27, Tom Lendacky wrote: > The base VmgExitLib library provides a default limited interface. As it > does not provide full support, create an OVMF version of this library to > begin the process of providing full support of SEV-ES within OVMF. > > SEV-ES support is only provided for X64 builds, so only OvmfPkgX64.dsc is > updated to make use of the OvmfPkg version of the library. > > Cc: Jordan Justen <jordan.l.jus...@intel.com> > Cc: Laszlo Ersek <ler...@redhat.com> > Cc: Ard Biesheuvel <ard.biesheu...@arm.com> > Acked-by: Laszlo Ersek <ler...@redhat.com> > Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com> > --- > OvmfPkg/OvmfPkgX64.dsc | 2 +- > OvmfPkg/Library/VmgExitLib/VmgExitLib.inf | 36 +++++ > OvmfPkg/Library/VmgExitLib/VmgExitLib.c | 159 ++++++++++++++++++++ > OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 81 ++++++++++ > 4 files changed, 277 insertions(+), 1 deletion(-) > > diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc > index 0b9189ab1e38..b5f3859420d0 100644 > --- a/OvmfPkg/OvmfPkgX64.dsc > +++ b/OvmfPkg/OvmfPkgX64.dsc > @@ -232,7 +232,7 @@ [LibraryClasses] > > [LibraryClasses.common] > BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf > - VmgExitLib|UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.inf > + VmgExitLib|OvmfPkg/Library/VmgExitLib/VmgExitLib.inf > > [LibraryClasses.common.SEC] > TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseRomAcpiTimerLib.inf > diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitLib.inf > b/OvmfPkg/Library/VmgExitLib/VmgExitLib.inf > new file mode 100644 > index 000000000000..8acdee2349b4 > --- /dev/null > +++ b/OvmfPkg/Library/VmgExitLib/VmgExitLib.inf > @@ -0,0 +1,36 @@ > +## @file > +# VMGEXIT Support Library. > +# > +# Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR> > +# SPDX-License-Identifier: BSD-2-Clause-Patent > +# > +## > + > +[Defines] > + INF_VERSION = 0x00010005 > + BASE_NAME = VmgExitLib > + FILE_GUID = 0e923c25-13cd-430b-8714-ffe85652a97b > + MODULE_TYPE = BASE > + VERSION_STRING = 1.0 > + LIBRARY_CLASS = VmgExitLib > + > +# > +# The following information is for reference only and not required by the > build tools. > +# > +# VALID_ARCHITECTURES = X64 > +# > + > +[Sources.common] > + VmgExitLib.c > + VmgExitVcHandler.c > + > +[Packages] > + MdePkg/MdePkg.dec > + UefiCpuPkg/UefiCpuPkg.dec > + OvmfPkg/OvmfPkg.dec > + > +[LibraryClasses] > + BaseLib > + DebugLib > + BaseMemoryLib > +
(1) Please keep the individual sections sorted alphabetically. > diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitLib.c > b/OvmfPkg/Library/VmgExitLib/VmgExitLib.c > new file mode 100644 > index 000000000000..0ca164a33eb4 > --- /dev/null > +++ b/OvmfPkg/Library/VmgExitLib/VmgExitLib.c > @@ -0,0 +1,159 @@ > +/** @file > + VMGEXIT Support Library. > + > + Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR> > + SPDX-License-Identifier: BSD-2-Clause-Patent > + > +**/ > + > +#include <Base.h> > +#include <Uefi.h> > +#include <Library/BaseMemoryLib.h> > +#include <Library/VmgExitLib.h> > +#include <Register/Amd/Msr.h> > + > +/** > + Check for VMGEXIT error > + > + Check if the hypervisor has returned an error after completion of the > VMGEXIT > + by examining the SwExitInfo1 field of the GHCB. > + > + @param[in] Ghcb A pointer to the GHCB > + > + @return 0 VMGEXIT succeeded. > + @return Others VMGEXIT processing did not succeed. Exception > number to > + be propagated. (2) You misunderstood my @return / @retval explanation from v8: 23c7dfb3-56ac-b080-2736-687cd11d51a0@redhat.com">http://mid.mail-archive.com/23c7dfb3-56ac-b080-2736-687cd11d51a0@redhat.com https://edk2.groups.io/g/devel/message/60047 We have two formats. (2a) "@return Natural language explanation" In this format, there is *NO CONSTANT* in the documentation. The comment only explains in natural language what the function returns. In the message linked above, I brought the example: @return IOIO event information values. That was *not* a typo. (2b) The other format is "@retval CONSTANT Natural language explanation". In this case, the exact return value is given, and then explained. In the v8 review, I mentioned that "@retval Others" is wrong, even though it is used in several places in the edk2 tree. That's because "Others" is not a constant. The right way to put "@retval Others" is to replace it with *just* "@return". In other words, *drop* the "Others" non-constant, replace "@retval" with "@return", and reformulate the natural language text. In the v8 review, I also mentioned that "@retval Natural language explanation" is also wrong, because it's either missing a constant, or it should use "@return". Unfortunately, in response, you seem to have replaced @retval 0 @retval Others with @return 0 @return Others (i.e., just replaced "@retval" with "@return"). And that update is wrong, on *both* lines: - "@retval 0" was correct. It should not have been updated. - "@retval Others" was indeed wrong, but "@return Others" is *also* wrong. It should be just "@return", not "@return Others". Specifically, the right comment would be: @retval 0 VMGEXIT succeeded. @return Exception number to be propagated. VMGEXIT processing did not succeed. If you read it aloud, it will make sense. Anyway, I'm exhausted. We can address this in a follow-up series, if we want to. Keep the ACK, and no v10 is needed just for these comments. Thanks Laszlo > + > +**/ > +STATIC > +UINT64 > +VmgExitErrorCheck ( > + IN GHCB *Ghcb > + ) > +{ > + GHCB_EVENT_INJECTION Event; > + GHCB_EXIT_INFO ExitInfo; > + UINT64 Status; > + > + ExitInfo.Uint64 = Ghcb->SaveArea.SwExitInfo1; > + ASSERT ((ExitInfo.Elements.Lower32Bits == 0) || > + (ExitInfo.Elements.Lower32Bits == 1)); > + > + Status = 0; > + if (ExitInfo.Elements.Lower32Bits == 0) { > + return Status; > + } > + > + if (ExitInfo.Elements.Lower32Bits == 1) { > + ASSERT (Ghcb->SaveArea.SwExitInfo2 != 0); > + > + // > + // Check that the return event is valid > + // > + Event.Uint64 = Ghcb->SaveArea.SwExitInfo2; > + if (Event.Elements.Valid && > + Event.Elements.Type == GHCB_EVENT_INJECTION_TYPE_EXCEPTION) { > + switch (Event.Elements.Vector) { > + case GP_EXCEPTION: > + case UD_EXCEPTION: > + // > + // Use returned event as return code > + // > + Status = Event.Uint64; > + } > + } > + } > + > + if (Status == 0) { > + GHCB_EVENT_INJECTION GpEvent; > + > + GpEvent.Uint64 = 0; > + GpEvent.Elements.Vector = GP_EXCEPTION; > + GpEvent.Elements.Type = GHCB_EVENT_INJECTION_TYPE_EXCEPTION; > + GpEvent.Elements.Valid = 1; > + > + Status = GpEvent.Uint64; > + } > + > + return Status; > +} > + > +/** > + Perform VMGEXIT. > + > + Sets the necessary fields of the GHCB, invokes the VMGEXIT instruction and > + then handles the return actions. > + > + @param[in, out] Ghcb A pointer to the GHCB > + @param[in] ExitCode VMGEXIT code to be assigned to the SwExitCode > + field of the GHCB. > + @param[in] ExitInfo1 VMGEXIT information to be assigned to the > + SwExitInfo1 field of the GHCB. > + @param[in] ExitInfo2 VMGEXIT information to be assigned to the > + SwExitInfo2 field of the GHCB. > + > + @return 0 VMGEXIT succeeded. > + @return Others VMGEXIT processing did not succeed. Exception > + event to be propagated. > + > +**/ > +UINT64 > +EFIAPI > +VmgExit ( > + IN OUT GHCB *Ghcb, > + IN UINT64 ExitCode, > + IN UINT64 ExitInfo1, > + IN UINT64 ExitInfo2 > + ) > +{ > + Ghcb->SaveArea.SwExitCode = ExitCode; > + Ghcb->SaveArea.SwExitInfo1 = ExitInfo1; > + Ghcb->SaveArea.SwExitInfo2 = ExitInfo2; > + > + // > + // Guest memory is used for the guest-hypervisor communication, so fence > + // the invocation of the VMGEXIT instruction to ensure GHCB accesses are > + // synchronized properly. > + // > + MemoryFence (); > + AsmVmgExit (); > + MemoryFence (); > + > + return VmgExitErrorCheck (Ghcb); > +} > + > +/** > + Perform pre-VMGEXIT initialization/preparation. > + > + Performs the necessary steps in preparation for invoking VMGEXIT. Must be > + called before setting any fields within the GHCB. > + > + @param[in, out] Ghcb A pointer to the GHCB > + > +**/ > +VOID > +EFIAPI > +VmgInit ( > + IN OUT GHCB *Ghcb > + ) > +{ > + SetMem (&Ghcb->SaveArea, sizeof (Ghcb->SaveArea), 0); > +} > + > +/** > + Perform post-VMGEXIT cleanup. > + > + Performs the necessary steps to cleanup after invoking VMGEXIT. Must be > + called after obtaining needed fields within the GHCB. > + > + @param[in, out] Ghcb A pointer to the GHCB > + > +**/ > +VOID > +EFIAPI > +VmgDone ( > + IN OUT GHCB *Ghcb > + ) > +{ > +} > + > diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c > b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c > new file mode 100644 > index 000000000000..b6a955ed8088 > --- /dev/null > +++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c > @@ -0,0 +1,81 @@ > +/** @file > + X64 #VC Exception Handler functon. > + > + Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR> > + SPDX-License-Identifier: BSD-2-Clause-Patent > + > +**/ > + > +#include <Base.h> > +#include <Uefi.h> > +#include <Library/BaseMemoryLib.h> > +#include <Library/VmgExitLib.h> > +#include <Register/Amd/Msr.h> > + > +/** > + Handle a #VC exception. > + > + Performs the necessary processing to handle a #VC exception. > + > + @param[in, out] ExceptionType Pointer to an EFI_EXCEPTION_TYPE to be set > + as value to use on error. > + @param[in, out] SystemContext Pointer to EFI_SYSTEM_CONTEXT > + > + @retval EFI_SUCCESS Exception handled > + @retval EFI_UNSUPPORTED #VC not supported, (new) exception value to > + propagate provided > + @retval EFI_PROTOCOL_ERROR #VC handling failed, (new) exception value > to > + propagate provided > + > +**/ > +EFI_STATUS > +EFIAPI > +VmgExitHandleVc ( > + IN OUT EFI_EXCEPTION_TYPE *ExceptionType, > + IN OUT EFI_SYSTEM_CONTEXT SystemContext > + ) > +{ > + MSR_SEV_ES_GHCB_REGISTER Msr; > + EFI_SYSTEM_CONTEXT_X64 *Regs; > + GHCB *Ghcb; > + UINT64 ExitCode, Status; > + EFI_STATUS VcRet; > + > + VcRet = EFI_SUCCESS; > + > + Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB); > + ASSERT (Msr.GhcbInfo.Function == 0); > + ASSERT (Msr.Ghcb != 0); > + > + Regs = SystemContext.SystemContextX64; > + Ghcb = Msr.Ghcb; > + > + VmgInit (Ghcb); > + > + ExitCode = Regs->ExceptionData; > + switch (ExitCode) { > + default: > + Status = VmgExit (Ghcb, SVM_EXIT_UNSUPPORTED, ExitCode, 0); > + if (Status == 0) { > + Regs->ExceptionData = 0; > + *ExceptionType = GP_EXCEPTION; > + } else { > + GHCB_EVENT_INJECTION Event; > + > + Event.Uint64 = Status; > + if (Event.Elements.ErrorCodeValid != 0) { > + Regs->ExceptionData = Event.Elements.ErrorCode; > + } else { > + Regs->ExceptionData = 0; > + } > + > + *ExceptionType = Event.Elements.Vector; > + } > + > + VcRet = EFI_PROTOCOL_ERROR; > + } > + > + VmgDone (Ghcb); > + > + return VcRet; > +} > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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