diff options
| author |   Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
|---|---|---|
| committer | Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
| commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
| tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/edk2/OvmfPkg/SmmControl2Dxe/SmiFeatures.c | |
| parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) | |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/edk2/OvmfPkg/SmmControl2Dxe/SmiFeatures.c')
| -rw-r--r-- | roms/edk2/OvmfPkg/SmmControl2Dxe/SmiFeatures.c | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/roms/edk2/OvmfPkg/SmmControl2Dxe/SmiFeatures.c b/roms/edk2/OvmfPkg/SmmControl2Dxe/SmiFeatures.c new file mode 100644 index 000000000..c9d875543 --- /dev/null +++ b/roms/edk2/OvmfPkg/SmmControl2Dxe/SmiFeatures.c @@ -0,0 +1,262 @@ +/**@file
+ Negotiate SMI features with QEMU, and configure UefiCpuPkg/PiSmmCpuDxeSmm
+ accordingly.
+
+ Copyright (C) 2016-2017, Red Hat, Inc.
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MemEncryptSevLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PcdLib.h>
+#include <Library/QemuFwCfgLib.h>
+#include <Library/QemuFwCfgS3Lib.h>
+
+#include "SmiFeatures.h"
+
+//
+// The following bit value stands for "broadcast SMI" in the
+// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.
+//
+#define ICH9_LPC_SMI_F_BROADCAST BIT0
+//
+// The following bit value stands for "enable CPU hotplug, and inject an SMI
+// with control value ICH9_APM_CNT_CPU_HOTPLUG upon hotplug", in the
+// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.
+//
+#define ICH9_LPC_SMI_F_CPU_HOTPLUG BIT1
+
+//
+// Provides a scratch buffer (allocated in EfiReservedMemoryType type memory)
+// for the S3 boot script fragment to write to and read from.
+//
+#pragma pack (1)
+typedef union {
+ UINT64 Features;
+ UINT8 FeaturesOk;
+} SCRATCH_BUFFER;
+#pragma pack ()
+
+//
+// These carry the selector keys of the "etc/smi/requested-features" and
+// "etc/smi/features-ok" fw_cfg files from NegotiateSmiFeatures() to
+// AppendFwCfgBootScript().
+//
+STATIC FIRMWARE_CONFIG_ITEM mRequestedFeaturesItem;
+STATIC FIRMWARE_CONFIG_ITEM mFeaturesOkItem;
+
+//
+// Carries the negotiated SMI features from NegotiateSmiFeatures() to
+// AppendFwCfgBootScript().
+//
+STATIC UINT64 mSmiFeatures;
+
+/**
+ Negotiate SMI features with QEMU.
+
+ @retval FALSE If SMI feature negotiation is not supported by QEMU. This is
+ not an error, it just means that SaveSmiFeatures() should not
+ be called.
+
+ @retval TRUE SMI feature negotiation is supported, and it has completed
+ successfully as well. (Failure to negotiate is a fatal error
+ and the function never returns in that case.)
+**/
+BOOLEAN
+NegotiateSmiFeatures (
+ VOID
+ )
+{
+ FIRMWARE_CONFIG_ITEM SupportedFeaturesItem;
+ UINTN SupportedFeaturesSize;
+ UINTN RequestedFeaturesSize;
+ UINTN FeaturesOkSize;
+ UINT64 RequestedFeaturesMask;
+
+ //
+ // Look up the fw_cfg files used for feature negotiation. The selector keys
+ // of "etc/smi/requested-features" and "etc/smi/features-ok" are saved
+ // statically. If the files are missing, then QEMU doesn't support SMI
+ // feature negotiation.
+ //
+ if (RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/supported-features",
+ &SupportedFeaturesItem, &SupportedFeaturesSize)) ||
+ RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/requested-features",
+ &mRequestedFeaturesItem, &RequestedFeaturesSize)) ||
+ RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/features-ok",
+ &mFeaturesOkItem, &FeaturesOkSize))) {
+ DEBUG ((DEBUG_INFO, "%a: SMI feature negotiation unavailable\n",
+ __FUNCTION__));
+ return FALSE;
+ }
+
+ //
+ // If the files are present but their sizes disagree with us, that's a fatal
+ // error (we can't trust the behavior of SMIs either way).
+ //
+ if (SupportedFeaturesSize != sizeof mSmiFeatures ||
+ RequestedFeaturesSize != sizeof mSmiFeatures ||
+ FeaturesOkSize != sizeof (UINT8)) {
+ DEBUG ((DEBUG_ERROR, "%a: size mismatch in feature negotiation\n",
+ __FUNCTION__));
+ goto FatalError;
+ }
+
+ //
+ // Get the features supported by the host.
+ //
+ QemuFwCfgSelectItem (SupportedFeaturesItem);
+ QemuFwCfgReadBytes (sizeof mSmiFeatures, &mSmiFeatures);
+
+ //
+ // We want broadcast SMI, SMI on CPU hotplug, and nothing else.
+ //
+ RequestedFeaturesMask = ICH9_LPC_SMI_F_BROADCAST;
+ if (!MemEncryptSevIsEnabled ()) {
+ //
+ // For now, we only support hotplug with SEV disabled.
+ //
+ RequestedFeaturesMask |= ICH9_LPC_SMI_F_CPU_HOTPLUG;
+ }
+ mSmiFeatures &= RequestedFeaturesMask;
+ QemuFwCfgSelectItem (mRequestedFeaturesItem);
+ QemuFwCfgWriteBytes (sizeof mSmiFeatures, &mSmiFeatures);
+
+ //
+ // Invoke feature validation in QEMU. If the selection is accepted, the
+ // features will be locked down. If the selection is rejected, feature
+ // negotiation remains open; however we don't know what to do in that case,
+ // so that's a fatal error.
+ //
+ QemuFwCfgSelectItem (mFeaturesOkItem);
+ if (QemuFwCfgRead8 () != 1) {
+ DEBUG ((DEBUG_ERROR, "%a: negotiation failed for feature bitmap 0x%Lx\n",
+ __FUNCTION__, mSmiFeatures));
+ goto FatalError;
+ }
+
+ if ((mSmiFeatures & ICH9_LPC_SMI_F_BROADCAST) == 0) {
+ //
+ // If we can't get broadcast SMIs from QEMU, that's acceptable too,
+ // although not optimal.
+ //
+ DEBUG ((DEBUG_INFO, "%a: SMI broadcast unavailable\n", __FUNCTION__));
+ } else {
+ //
+ // Configure the traditional AP sync / SMI delivery mode for
+ // PiSmmCpuDxeSmm. Effectively, restore the UefiCpuPkg defaults, from which
+ // the original QEMU behavior (i.e., unicast SMI) used to differ.
+ //
+ if (RETURN_ERROR (PcdSet64S (PcdCpuSmmApSyncTimeout, 1000000)) ||
+ RETURN_ERROR (PcdSet8S (PcdCpuSmmSyncMode, 0x00))) {
+ DEBUG ((DEBUG_ERROR, "%a: PiSmmCpuDxeSmm PCD configuration failed\n",
+ __FUNCTION__));
+ goto FatalError;
+ }
+ DEBUG ((DEBUG_INFO, "%a: using SMI broadcast\n", __FUNCTION__));
+ }
+
+ if ((mSmiFeatures & ICH9_LPC_SMI_F_CPU_HOTPLUG) == 0) {
+ DEBUG ((DEBUG_INFO, "%a: CPU hotplug not negotiated\n", __FUNCTION__));
+ } else {
+ DEBUG ((DEBUG_INFO, "%a: CPU hotplug with SMI negotiated\n",
+ __FUNCTION__));
+ }
+
+ //
+ // Negotiation successful (although we may not have gotten the optimal
+ // feature set).
+ //
+ return TRUE;
+
+FatalError:
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+ //
+ // Keep the compiler happy.
+ //
+ return FALSE;
+}
+
+/**
+ FW_CFG_BOOT_SCRIPT_CALLBACK_FUNCTION provided to QemuFwCfgS3Lib.
+**/
+STATIC
+VOID
+EFIAPI
+AppendFwCfgBootScript (
+ IN OUT VOID *Context, OPTIONAL
+ IN OUT VOID *ExternalScratchBuffer
+ )
+{
+ SCRATCH_BUFFER *ScratchBuffer;
+ RETURN_STATUS Status;
+
+ ScratchBuffer = ExternalScratchBuffer;
+
+ //
+ // Write the negotiated feature bitmap into "etc/smi/requested-features".
+ //
+ ScratchBuffer->Features = mSmiFeatures;
+ Status = QemuFwCfgS3ScriptWriteBytes (mRequestedFeaturesItem,
+ sizeof ScratchBuffer->Features);
+ if (RETURN_ERROR (Status)) {
+ goto FatalError;
+ }
+
+ //
+ // Read back "etc/smi/features-ok". This invokes the feature validation &
+ // lockdown. (The validation succeeded at first boot.)
+ //
+ Status = QemuFwCfgS3ScriptReadBytes (mFeaturesOkItem,
+ sizeof ScratchBuffer->FeaturesOk);
+ if (RETURN_ERROR (Status)) {
+ goto FatalError;
+ }
+
+ //
+ // If "etc/smi/features-ok" read as 1, we're good. Otherwise, hang the S3
+ // resume process.
+ //
+ Status = QemuFwCfgS3ScriptCheckValue (&ScratchBuffer->FeaturesOk,
+ sizeof ScratchBuffer->FeaturesOk, MAX_UINT8, 1);
+ if (RETURN_ERROR (Status)) {
+ goto FatalError;
+ }
+
+ DEBUG ((DEBUG_VERBOSE, "%a: SMI feature negotiation boot script saved\n",
+ __FUNCTION__));
+ return;
+
+FatalError:
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
+
+
+/**
+ Append a boot script fragment that will re-select the previously negotiated
+ SMI features during S3 resume.
+**/
+VOID
+SaveSmiFeatures (
+ VOID
+ )
+{
+ RETURN_STATUS Status;
+
+ //
+ // We are already running at TPL_CALLBACK, on the stack of
+ // OnS3SaveStateInstalled(). But that's okay, we can easily queue more
+ // notification functions while executing a notification function.
+ //
+ Status = QemuFwCfgS3CallWhenBootScriptReady (AppendFwCfgBootScript, NULL,
+ sizeof (SCRATCH_BUFFER));
+ if (RETURN_ERROR (Status)) {
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+ }
+}
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