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-rw-r--r--src/security/intel/txt/ramstage.c41
-rw-r--r--src/security/intel/txt/txt_platform.h12
2 files changed, 46 insertions, 7 deletions
diff --git a/src/security/intel/txt/ramstage.c b/src/security/intel/txt/ramstage.c
index 263bc9daa6..f532a2fbd8 100644
--- a/src/security/intel/txt/ramstage.c
+++ b/src/security/intel/txt/ramstage.c
@@ -13,6 +13,7 @@
#include <types.h>
#include "txt.h"
+#include "txt_platform.h"
#include "txt_register.h"
#include "txt_getsec.h"
@@ -233,16 +234,42 @@ static void lockdown_intel_txt(void *unused)
printk(BIOS_INFO, "TEE-TXT: DPR capable %x\n", dpr_capable);
if (dpr_capable) {
- /* Protect 3 MiB below TSEG and lock register */
- union dpr_register dpr = {
- .lock = 1,
- .size = 3,
- .top = tseg_base / MiB,
- };
- write64((void *)TXT_DPR, dpr.raw);
+ /* Verify the DPR settings on the MCH and mirror them to TXT public space */
+ union dpr_register dpr = txt_get_chipset_dpr();
+
+ printk(BIOS_DEBUG, "TEE-TXT: MCH DPR 0x%08x\n", dpr.raw);
+
+ printk(BIOS_DEBUG, "TEE-TXT: MCH DPR base @ 0x%08x size %u MiB\n",
+ (dpr.top - dpr.size) * MiB, dpr.size);
// DPR TODO: implement SA_ENABLE_DPR in the intelblocks
+ if (!dpr.lock) {
+ printk(BIOS_ERR, "TEE-TXT: MCH DPR not locked.\n");
+ return;
+ }
+
+ if (!dpr.epm || !dpr.prs) {
+ printk(BIOS_ERR, "TEE-TXT: MCH DPR protection not active.\n");
+ return;
+ }
+
+ if (dpr.size < 3) {
+ printk(BIOS_ERR, "TEE-TXT: MCH DPR configured size is too small.\n");
+ return;
+ }
+
+ if (dpr.top * MiB != tseg_base) {
+ printk(BIOS_ERR, "TEE-TXT: MCH DPR top does not equal TSEG base.\n");
+ return;
+ }
+
+ /* Clear reserved bits */
+ dpr.prs = 0;
+ dpr.epm = 0;
+
+ write64((void *)TXT_DPR, dpr.raw);
+
printk(BIOS_INFO, "TEE-TXT: TXT.DPR 0x%08x\n",
read32((void *)TXT_DPR));
}
diff --git a/src/security/intel/txt/txt_platform.h b/src/security/intel/txt/txt_platform.h
new file mode 100644
index 0000000000..8881cab331
--- /dev/null
+++ b/src/security/intel/txt/txt_platform.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __SECURITY_INTEL_TXT_PLATFORM_H__
+#define __SECURITY_INTEL_TXT_PLATFORM_H__
+
+#include <types.h>
+#include "txt_register.h"
+
+/* Prototypes to be defined in chipset code */
+union dpr_register txt_get_chipset_dpr(void);
+
+#endif /* __SECURITY_INTEL_TXT_PLATFORM_H__ */