diff options
Diffstat (limited to 'OvmfPkg/PlatformPei/MemTypeInfo.c')
| -rw-r--r-- | OvmfPkg/PlatformPei/MemTypeInfo.c | 159 |
1 files changed, 113 insertions, 46 deletions
diff --git a/OvmfPkg/PlatformPei/MemTypeInfo.c b/OvmfPkg/PlatformPei/MemTypeInfo.c index 8100a2db7d..d287fb9d7d 100644 --- a/OvmfPkg/PlatformPei/MemTypeInfo.c +++ b/OvmfPkg/PlatformPei/MemTypeInfo.c @@ -1,7 +1,5 @@ /** @file
- Produce a default memory type information HOB unless we can determine, from
- the existence of the "MemoryTypeInformation" variable, that the DXE IPL PEIM
- will produce the HOB.
+ Produce the memory type information HOB.
Copyright (C) 2017-2020, Red Hat, Inc.
@@ -25,7 +23,7 @@ // of BIN hints that made sense at a particular time, for some (now likely
// unknown) workloads / boot paths.
//
-STATIC EFI_MEMORY_TYPE_INFORMATION mDefaultMemoryTypeInformation[] = {
+STATIC EFI_MEMORY_TYPE_INFORMATION mMemoryTypeInformation[] = {
{ EfiACPIMemoryNVS, 0x004 },
{ EfiACPIReclaimMemory, 0x008 },
{ EfiReservedMemoryType, 0x004 },
@@ -42,75 +40,144 @@ BuildMemTypeInfoHob ( {
BuildGuidDataHob (
&gEfiMemoryTypeInformationGuid,
- mDefaultMemoryTypeInformation,
- sizeof mDefaultMemoryTypeInformation
+ mMemoryTypeInformation,
+ sizeof mMemoryTypeInformation
);
- DEBUG ((DEBUG_INFO, "%a: default memory type information HOB built\n",
- __FUNCTION__));
}
/**
- Notification function called when EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes
- available.
+ Refresh the mMemoryTypeInformation array (which we'll turn into the
+ MemoryTypeInformation HOB) from the MemoryTypeInformation UEFI variable.
- @param[in] PeiServices Indirect reference to the PEI Services Table.
- @param[in] NotifyDescriptor Address of the notification descriptor data
- structure.
- @param[in] Ppi Address of the PPI that was installed.
+ Normally, the DXE IPL PEIM builds the HOB from the UEFI variable. But it does
+ so *transparently*. Instead, we consider the UEFI variable as a list of
+ hints, for updating our HOB defaults:
- @return Status of the notification. The status code returned from this
- function is ignored.
+ - Record types not covered in mMemoryTypeInformation are ignored. In
+ particular, this hides record types from the UEFI variable that may lead to
+ reboots without benefiting SMM security, such as EfiBootServicesData.
+
+ - Records that would lower the defaults in mMemoryTypeInformation are also
+ ignored.
+
+ @param[in] ReadOnlyVariable2 The EFI_PEI_READ_ONLY_VARIABLE2_PPI used for
+ retrieving the MemoryTypeInformation UEFI
+ variable.
**/
STATIC
-EFI_STATUS
-EFIAPI
-OnReadOnlyVariable2Available (
- IN EFI_PEI_SERVICES **PeiServices,
- IN EFI_PEI_NOTIFY_DESCRIPTOR *NotifyDescriptor,
- IN VOID *Ppi
+VOID
+RefreshMemTypeInfo (
+ IN EFI_PEI_READ_ONLY_VARIABLE2_PPI *ReadOnlyVariable2
)
{
- EFI_PEI_READ_ONLY_VARIABLE2_PPI *ReadOnlyVariable2;
- UINTN DataSize;
- EFI_STATUS Status;
-
- DEBUG ((DEBUG_VERBOSE, "%a\n", __FUNCTION__));
+ UINTN DataSize;
+ EFI_MEMORY_TYPE_INFORMATION Entries[EfiMaxMemoryType + 1];
+ EFI_STATUS Status;
+ UINTN NumEntries;
+ UINTN HobRecordIdx;
//
- // Check if the "MemoryTypeInformation" variable exists, in the
+ // Read the MemoryTypeInformation UEFI variable from the
// gEfiMemoryTypeInformationGuid namespace.
//
- ReadOnlyVariable2 = Ppi;
- DataSize = 0;
+ DataSize = sizeof Entries;
Status = ReadOnlyVariable2->GetVariable (
ReadOnlyVariable2,
EFI_MEMORY_TYPE_INFORMATION_VARIABLE_NAME,
&gEfiMemoryTypeInformationGuid,
NULL,
&DataSize,
- NULL
+ Entries
);
- switch (Status) {
- case EFI_BUFFER_TOO_SMALL:
+ if (EFI_ERROR (Status)) {
//
- // The variable exists; the DXE IPL PEIM will build the HOB from it.
+ // If the UEFI variable does not exist (EFI_NOT_FOUND), we can't use it for
+ // udpating mMemoryTypeInformation.
//
- break;
- case EFI_NOT_FOUND:
+ // If the UEFI variable exists but Entries is too small to hold it
+ // (EFI_BUFFER_TOO_SMALL), then the variable contents are arguably invalid.
+ // That's because Entries has room for every distinct EFI_MEMORY_TYPE,
+ // including the terminator record with EfiMaxMemoryType. Thus, we can't
+ // use the UEFI variable for updating mMemoryTypeInformation.
//
- // The variable does not exist; install the default memory type information
- // HOB.
+ // If the UEFI variable couldn't be read for some other reason, we
+ // similarly can't use it for udpating mMemoryTypeInformation.
//
- BuildMemTypeInfoHob ();
- break;
- default:
- DEBUG ((DEBUG_ERROR, "%a: unexpected: GetVariable(): %r\n", __FUNCTION__,
- Status));
- ASSERT (FALSE);
- CpuDeadLoop ();
- break;
+ DEBUG ((DEBUG_ERROR, "%a: GetVariable(): %r\n", __FUNCTION__, Status));
+ return;
}
+ //
+ // Sanity-check the UEFI variable size against the record size.
+ //
+ if (DataSize % sizeof Entries[0] != 0) {
+ DEBUG ((DEBUG_ERROR, "%a: invalid UEFI variable size %Lu\n", __FUNCTION__,
+ (UINT64)DataSize));
+ return;
+ }
+ NumEntries = DataSize / sizeof Entries[0];
+
+ //
+ // For each record in mMemoryTypeInformation, except the terminator record,
+ // look up the first match (if any) in the UEFI variable, based on the memory
+ // type.
+ //
+ for (HobRecordIdx = 0;
+ HobRecordIdx < ARRAY_SIZE (mMemoryTypeInformation) - 1;
+ HobRecordIdx++) {
+ EFI_MEMORY_TYPE_INFORMATION *HobRecord;
+ UINTN Idx;
+ EFI_MEMORY_TYPE_INFORMATION *VariableRecord;
+
+ HobRecord = &mMemoryTypeInformation[HobRecordIdx];
+
+ for (Idx = 0; Idx < NumEntries; Idx++) {
+ VariableRecord = &Entries[Idx];
+
+ if (VariableRecord->Type == HobRecord->Type) {
+ break;
+ }
+ }
+
+ //
+ // If there is a match, allow the UEFI variable to increase NumberOfPages.
+ //
+ if (Idx < NumEntries &&
+ HobRecord->NumberOfPages < VariableRecord->NumberOfPages) {
+ DEBUG ((DEBUG_VERBOSE, "%a: Type 0x%x: NumberOfPages 0x%x -> 0x%x\n",
+ __FUNCTION__, HobRecord->Type, HobRecord->NumberOfPages,
+ VariableRecord->NumberOfPages));
+
+ HobRecord->NumberOfPages = VariableRecord->NumberOfPages;
+ }
+ }
+}
+
+/**
+ Notification function called when EFI_PEI_READ_ONLY_VARIABLE2_PPI becomes
+ available.
+
+ @param[in] PeiServices Indirect reference to the PEI Services Table.
+ @param[in] NotifyDescriptor Address of the notification descriptor data
+ structure.
+ @param[in] Ppi Address of the PPI that was installed.
+
+ @return Status of the notification. The status code returned from this
+ function is ignored.
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+OnReadOnlyVariable2Available (
+ IN EFI_PEI_SERVICES **PeiServices,
+ IN EFI_PEI_NOTIFY_DESCRIPTOR *NotifyDescriptor,
+ IN VOID *Ppi
+ )
+{
+ DEBUG ((DEBUG_VERBOSE, "%a\n", __FUNCTION__));
+
+ RefreshMemTypeInfo (Ppi);
+ BuildMemTypeInfoHob ();
return EFI_SUCCESS;
}
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