diff --git a/src/commonlib/bsd/include/commonlib/bsd/cbmem_id.h b/src/commonlib/bsd/include/commonlib/bsd/cbmem_id.h
index 0431626f2c..df0e0d0b67 100644
--- a/src/commonlib/bsd/include/commonlib/bsd/cbmem_id.h
+++ b/src/commonlib/bsd/include/commonlib/bsd/cbmem_id.h
@@ -7,6 +7,7 @@
 #define CBMEM_ID_ACPI_BERT	0x42455254
 #define CBMEM_ID_ACPI_CNVS	0x434e5653
 #define CBMEM_ID_ACPI_GNVS	0x474e5653
+#define CBMEM_ID_OPAL_S3_SCRATCH 0x3353504f /* 'OPS3' */
 #define CBMEM_ID_ACPI_HEST	0x48455354
 #define CBMEM_ID_ACPI_UCSI	0x55435349
 #define CBMEM_ID_AFTER_CAR	0xc4787a93
@@ -100,6 +101,7 @@
 	{ CBMEM_ID_ACPI_BERT,		"ACPI BERT  " }, \
 	{ CBMEM_ID_ACPI_CNVS,		"CHROMEOS NVS" }, \
 	{ CBMEM_ID_ACPI_GNVS,		"ACPI GNVS  " }, \
+	{ CBMEM_ID_OPAL_S3_SCRATCH,	"OPAL S3 SCR" }, \
 	{ CBMEM_ID_ACPI_HEST,		"ACPI HEST  " }, \
 	{ CBMEM_ID_ACPI_UCSI,		"ACPI UCSI  " }, \
 	{ CBMEM_ID_AGESA_RUNTIME,	"AGESA RSVD " }, \
diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig
index 7a701bb9d6..c049d4b124 100644
--- a/src/cpu/x86/Kconfig
+++ b/src/cpu/x86/Kconfig
@@ -196,6 +196,24 @@ config SMM_MODULE_STACK_SIZE
 	  This option determines the size of the stack within the SMM handler
 	  modules.
 
+config SMM_OPAL_S3_SCRATCH_CBMEM
+	bool
+	depends on HAVE_ACPI_RESUME
+	default n
+	help
+	  Allocate a coreboot-managed CBMEM region that can be used as a
+	  persistent (across S3) scratch buffer by SMM code performing OPAL/NVMe
+	  unlock on resume. The region is in CBMEM and therefore reserved from
+	  the OS via the memory map.
+
+config SMM_OPAL_S3_SCRATCH_SIZE
+	hex "OPAL S3 scratch size (bytes)"
+	depends on SMM_OPAL_S3_SCRATCH_CBMEM
+	default 0x4000
+	help
+	  Size of the CBMEM scratch buffer provided to the OPAL S3 unlock SMM
+	  handler. This buffer must be DMA-safe and persistent across S3.
+
 endif
 
 config SMM_LAPIC_REMAP_MITIGATION
diff --git a/src/cpu/x86/smm/smm_module_handler.c b/src/cpu/x86/smm/smm_module_handler.c
index 8bcda32b33..3f14d970d8 100644
--- a/src/cpu/x86/smm/smm_module_handler.c
+++ b/src/cpu/x86/smm/smm_module_handler.c
@@ -66,6 +66,14 @@ void smm_get_smmstore_com_buffer(uintptr_t *base, size_t *size)
 	*size = smm_runtime.smmstore_com_buffer_size;
 }
 
+#if CONFIG(SMM_OPAL_S3_SCRATCH_CBMEM)
+void smm_get_opal_s3_scratch_buffer(uintptr_t *base, size_t *size)
+{
+	*base = smm_runtime.opal_s3_scratch_base;
+	*size = smm_runtime.opal_s3_scratch_size;
+}
+#endif
+
 void smm_get_cbmemc_buffer(void **buffer_out, size_t *size_out)
 {
 	*buffer_out = smm_runtime.cbmemc;
diff --git a/src/cpu/x86/smm/smm_module_loader.c b/src/cpu/x86/smm/smm_module_loader.c
index dff2dde857..4946fe5a0f 100644
--- a/src/cpu/x86/smm/smm_module_loader.c
+++ b/src/cpu/x86/smm/smm_module_loader.c
@@ -366,6 +366,26 @@ static void setup_smihandler_params(struct smm_runtime *mod_params,
 		mod_params->smmstore_com_buffer_base = (uintptr_t)ptr;
 		mod_params->smmstore_com_buffer_size = info.block_size;
 	}
+
+#if CONFIG(SMM_OPAL_S3_SCRATCH_CBMEM)
+	/*
+	 * Provide a small, coreboot-managed CBMEM scratch region for SMM code.
+	 * CBMEM is reserved in the memory map, and persists across S3, making
+	 * it suitable for firmware-owned DMA buffers on resume. SMRAM is not
+	 * accessible to devices for DMA, so this scratch buffer must live
+	 * outside SMRAM.
+	 */
+	const size_t opal_s3_scratch_size = CONFIG_SMM_OPAL_S3_SCRATCH_SIZE;
+	void *scratch = cbmem_add(CBMEM_ID_OPAL_S3_SCRATCH, opal_s3_scratch_size);
+	if (!scratch) {
+		printk(BIOS_ERR, "SMM: Failed to allocate OPAL S3 scratch\n");
+		mod_params->opal_s3_scratch_base = 0;
+		mod_params->opal_s3_scratch_size = 0;
+	} else {
+		mod_params->opal_s3_scratch_base = (uintptr_t)scratch;
+		mod_params->opal_s3_scratch_size = opal_s3_scratch_size;
+	}
+#endif
 }
 
 static void print_region(const char *name, const struct region region)
diff --git a/src/include/cpu/x86/smm.h b/src/include/cpu/x86/smm.h
index 8c41623817..913bd37205 100644
--- a/src/include/cpu/x86/smm.h
+++ b/src/include/cpu/x86/smm.h
@@ -96,6 +96,10 @@ struct smm_runtime {
 	int smm_log_level;
 	uintptr_t smmstore_com_buffer_base;
 	size_t smmstore_com_buffer_size;
+#if CONFIG(SMM_OPAL_S3_SCRATCH_CBMEM)
+	uintptr_t opal_s3_scratch_base;
+	size_t opal_s3_scratch_size;
+#endif
 } __packed;
 
 struct smm_module_params {
@@ -238,5 +242,8 @@ bool smm_pci_resource_store_fill_resources(struct smm_pci_resource_info *slots,
 void smm_pci_resource_store_init(struct smm_runtime *smm_runtime);
 
 void smm_get_smmstore_com_buffer(uintptr_t *base, size_t *size);
+#if CONFIG(SMM_OPAL_S3_SCRATCH_CBMEM)
+void smm_get_opal_s3_scratch_buffer(uintptr_t *base, size_t *size);
+#endif
 
 #endif /* CPU_X86_SMM_H */