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edk2/SOURCES/0026-OvmfPkg-AmdSevDxe-Shim...

124 lines
4.2 KiB

From ca812e951cc824d6d7db16ec04a23a4b7fbb6830 Mon Sep 17 00:00:00 2001
From: Oliver Steffen <osteffen@redhat.com>
Date: Wed, 16 Aug 2023 12:09:40 +0200
Subject: [PATCH] OvmfPkg/AmdSevDxe: Shim Reboot workaround (RHEL only)
RH-Author: Oliver Steffen <osteffen@redhat.com>
RH-MergeRequest: 46: OvmfPkg/AmdSevDxe: Shim Reboot workaround (RHEL only)
RH-Bugzilla: 2218196
RH-Acked-by: Gerd Hoffmann <None>
RH-Commit: [1/1] 9bf3bb989e36253aa34bf82ecfe8faa7312e8d22 (osteffen/edk2)
Add a callback at the end of the Dxe phase that sets the
"FB_NO_REBOOT" variable under the Shim GUID.
This is a workaround for a boot loop in case a confidential
guest that uses shim is booted with a vtpm device present.
BZ 2218196
Signed-off-by: Oliver Steffen <osteffen@redhat.com>
patch_name: edk2-OvmfPkg-AmdSevDxe-Shim-Reboot-workaround-RHEL-only.patch
present_in_specfile: true
location_in_specfile: 44
---
OvmfPkg/AmdSevDxe/AmdSevDxe.c | 43 +++++++++++++++++++++++++++++++++
OvmfPkg/AmdSevDxe/AmdSevDxe.inf | 2 ++
2 files changed, 45 insertions(+)
diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.c b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
index d497a343d3..ca345e95da 100644
--- a/OvmfPkg/AmdSevDxe/AmdSevDxe.c
+++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.c
@@ -19,6 +19,7 @@
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Guid/ConfidentialComputingSevSnpBlob.h>
+#include <Guid/GlobalVariable.h>
#include <Library/PcdLib.h>
#include <Pi/PiDxeCis.h>
#include <Protocol/SevMemoryAcceptance.h>
@@ -28,6 +29,10 @@
// Present, initialized, tested bits defined in MdeModulePkg/Core/Dxe/DxeMain.h
#define EFI_MEMORY_INTERNAL_MASK 0x0700000000000000ULL
+static EFI_GUID ShimLockGuid = {
+ 0x605dab50, 0xe046, 0x4300, { 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23 }
+};
+
STATIC
EFI_STATUS
AllocateConfidentialComputingBlob (
@@ -191,6 +196,32 @@ STATIC EDKII_MEMORY_ACCEPT_PROTOCOL mMemoryAcceptProtocol = {
AmdSevMemoryAccept
};
+VOID
+EFIAPI
+PopulateVarstore (
+ EFI_EVENT Event,
+ VOID *Context
+ )
+{
+ EFI_SYSTEM_TABLE *SystemTable = (EFI_SYSTEM_TABLE *)Context;
+ EFI_STATUS Status;
+
+ DEBUG ((DEBUG_INFO, "Populating Varstore\n"));
+ UINT32 data = 1;
+
+ Status = SystemTable->RuntimeServices->SetVariable (
+ L"FB_NO_REBOOT",
+ &ShimLockGuid,
+ EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS,
+ sizeof (data),
+ &data
+ );
+ ASSERT_EFI_ERROR (Status);
+
+ Status = SystemTable->BootServices->CloseEvent (Event);
+ ASSERT_EFI_ERROR (Status);
+}
+
EFI_STATUS
EFIAPI
AmdSevDxeEntryPoint (
@@ -203,6 +234,7 @@ AmdSevDxeEntryPoint (
UINTN NumEntries;
UINTN Index;
CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION *SnpBootDxeTable;
+ EFI_EVENT PopulateVarstoreEvent;
//
// Do nothing when SEV is not enabled
@@ -211,6 +243,17 @@ AmdSevDxeEntryPoint (
return EFI_UNSUPPORTED;
}
+ // Shim fallback reboot workaround
+ Status = gBS->CreateEventEx (
+ EVT_NOTIFY_SIGNAL,
+ TPL_CALLBACK,
+ PopulateVarstore,
+ SystemTable,
+ &gEfiEndOfDxeEventGroupGuid,
+ &PopulateVarstoreEvent
+ );
+ ASSERT_EFI_ERROR (Status);
+
//
// Iterate through the GCD map and clear the C-bit from MMIO and NonExistent
// memory space. The NonExistent memory space will be used for mapping the
diff --git a/OvmfPkg/AmdSevDxe/AmdSevDxe.inf b/OvmfPkg/AmdSevDxe/AmdSevDxe.inf
index e7c7d526c9..09cbd2b0ca 100644
--- a/OvmfPkg/AmdSevDxe/AmdSevDxe.inf
+++ b/OvmfPkg/AmdSevDxe/AmdSevDxe.inf
@@ -54,6 +54,8 @@
[Guids]
gConfidentialComputingSevSnpBlobGuid
gEfiEventBeforeExitBootServicesGuid
+ gEfiEndOfDxeEventGroupGuid ## CONSUMES ## Event
+
[Pcd]
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId