From: Ashish Kalra <ashish.ka...@amd.com> Check for SEV live migration feature support, if detected setup a new UEFI enviroment variable to indicate OVMF support for SEV live migration.
This environment variable is created by UEFI but consumed by the (guest) linux kernel. This is actually part of a 3-way negotiation of the live migration feature between hypervisor, guest OVMF and guest kernel. Host indicates support for live migration, which is detected by OVMF and correspondingly OVMF sets this SetLiveMigrationEnabled UEFI variable, which is read by the guest kernel and it indicates to the guest kernel that both host and OVMF support and have enabled the live migration feature. The new runtime UEFI environment variable is set via the notification function registered for the EFI_END_OF_DXE_EVENT_GROUP_GUID event in AmdSevDxe driver. AmdSevDxe module is an apriori driver so it gets loaded between PEI and DXE phases and the SetVariable call will fail at the driver's entry point as the Variable DXE module is still not loaded yet. So we need to wait for an event notification which is signaled after the Variable DXE module is loaded, hence, using the EndOfDxe event notification to make this call. Signed-off-by: Ashish Kalra <ashish.ka...@amd.com> --- OvmfPkg/AmdSevDxe/AmdSevDxe.c | 67 ++++++++++++++++++++++ OvmfPkg/AmdSevDxe/AmdSevDxe.inf | 4 ++ OvmfPkg/Include/Guid/AmdSevMemEncryptLib.h | 20 +++++++ OvmfPkg/OvmfPkg.dec | 1 + 4 files changed, 92 insertions(+) create mode 100644 OvmfPkg/Include/Guid/AmdSevMemEncryptLib.h diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.c b/OvmfPkg/AmdSevDxe/AmdSevDxe.c index 662d3c4ccb..1453d68d81 100644 --- a/OvmfPkg/AmdSevDxe/AmdSevDxe.c +++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.c @@ -15,10 +15,13 @@ #include <Library/BaseMemoryLib.h> #include <Library/DebugLib.h> #include <Library/DxeServicesTableLib.h> +#include <Library/UefiRuntimeServicesTableLib.h> #include <Library/MemEncryptSevLib.h> #include <Library/MemoryAllocationLib.h> #include <Library/UefiBootServicesTableLib.h> #include <Guid/ConfidentialComputingSevSnpBlob.h> +#include <Guid/AmdSevMemEncryptLib.h> +#include <Guid/EventGroup.h> #include <Library/PcdLib.h> STATIC CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION mSnpBootDxeTable = { @@ -31,6 +34,39 @@ STATIC CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION mSnpBootDxeTable = { FixedPcdGet32 (PcdOvmfCpuidSize), }; +STATIC +VOID +EFIAPI +AmdSevDxeOnEndOfDxe ( + IN EFI_EVENT Event, + IN VOID *EventToSignal + ) +{ + EFI_STATUS Status; + BOOLEAN SevLiveMigrationEnabled; + + SevLiveMigrationEnabled = MemEncryptSevLiveMigrationIsEnabled (); + + if (SevLiveMigrationEnabled) { + Status = gRT->SetVariable ( + L"SevLiveMigrationEnabled", + &gAmdSevMemEncryptGuid, + EFI_VARIABLE_NON_VOLATILE | + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS, + sizeof SevLiveMigrationEnabled, + &SevLiveMigrationEnabled + ); + + DEBUG (( + DEBUG_INFO, + "%a: Setting SevLiveMigrationEnabled variable, status = %lx\n", + __FUNCTION__, + Status + )); + } +} + EFI_STATUS EFIAPI AmdSevDxeEntryPoint ( @@ -42,6 +78,7 @@ AmdSevDxeEntryPoint ( EFI_GCD_MEMORY_SPACE_DESCRIPTOR *AllDescMap; UINTN NumEntries; UINTN Index; + EFI_EVENT Event; // // Do nothing when SEV is not enabled @@ -158,5 +195,35 @@ AmdSevDxeEntryPoint ( ); } + // + // AmdSevDxe module is an apriori driver so it gets loaded between PEI + // and DXE phases and the SetVariable call will fail at the driver's + // entry point as the Variable DXE module is still not loaded yet. + // So we need to wait for an event notification which is signaled + // after the Variable DXE module is loaded, hence, using the + // EndOfDxe event notification to make this call. + // + // Register EFI_END_OF_DXE_EVENT_GROUP_GUID event. + // The notification function sets the runtime variable indicating OVMF + // support for SEV live migration. + // + Status = gBS->CreateEventEx ( + EVT_NOTIFY_SIGNAL, + TPL_CALLBACK, + AmdSevDxeOnEndOfDxe, + NULL, + &gEfiEndOfDxeEventGroupGuid, + &Event + ); + + if (EFI_ERROR (Status)) { + DEBUG (( + DEBUG_ERROR, + "%a: CreateEventEx(): %r\n", + __FUNCTION__, + Status + )); + } + return EFI_SUCCESS; } diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.inf b/OvmfPkg/AmdSevDxe/AmdSevDxe.inf index 9acf860cf2..42f8af0d0d 100644 --- a/OvmfPkg/AmdSevDxe/AmdSevDxe.inf +++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.inf @@ -52,3 +52,7 @@ [Pcd] gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId + +[Guids] + gAmdSevMemEncryptGuid + gEfiEndOfDxeEventGroupGuid ## CONSUMES ## Event diff --git a/OvmfPkg/Include/Guid/AmdSevMemEncryptLib.h b/OvmfPkg/Include/Guid/AmdSevMemEncryptLib.h new file mode 100644 index 0000000000..62d22e79a9 --- /dev/null +++ b/OvmfPkg/Include/Guid/AmdSevMemEncryptLib.h @@ -0,0 +1,20 @@ +/** @file + + AMD Memory Encryption GUID, define a new GUID for defining + new UEFI environment variables assocaiated with SEV Memory Encryption. + + Copyright (c) 2021, AMD Inc. All rights reserved.<BR> + + SPDX-License-Identifier: BSD-2-Clause-Patent + +**/ + +#ifndef __AMD_SEV_MEMENCRYPT_LIB_H__ +#define __AMD_SEV_MEMENCRYPT_LIB_H__ + +#define AMD_SEV_MEMENCRYPT_GUID \ +{0x0cf29b71, 0x9e51, 0x433a, {0xa3, 0xb7, 0x81, 0xf3, 0xab, 0x16, 0xb8, 0x75}} + +extern EFI_GUID gAmdSevMemEncryptGuid; + +#endif diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec index b9ca441202..0f415f24db 100644 --- a/OvmfPkg/OvmfPkg.dec +++ b/OvmfPkg/OvmfPkg.dec @@ -142,6 +142,7 @@ gConfidentialComputingSecretGuid = {0xadf956ad, 0xe98c, 0x484c, {0xae, 0x11, 0xb5, 0x1c, 0x7d, 0x33, 0x64, 0x47}} gConfidentialComputingSevSnpBlobGuid = {0x067b1f5f, 0xcf26, 0x44c5, {0x85, 0x54, 0x93, 0xd7, 0x77, 0x91, 0x2d, 0x42}} gUefiOvmfPkgPlatformInfoGuid = {0xdec9b486, 0x1f16, 0x47c7, {0x8f, 0x68, 0xdf, 0x1a, 0x41, 0x88, 0x8b, 0xa5}} + gAmdSevMemEncryptGuid = {0x0cf29b71, 0x9e51, 0x433a, {0xa3, 0xb7, 0x81, 0xf3, 0xab, 0x16, 0xb8, 0x75}} [Ppis] # PPI whose presence in the PPI database signals that the TPM base address -- 2.25.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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