Merging upstream version 6.8.9.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 45 insertions, 4 deletions

diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
index d07be9d05c..ddd4efdc79 100644
--- a/arch/x86/coco/core.c
+++ b/arch/x86/coco/core.c
@@ -3,13 +3,17 @@
  * Confidential Computing Platform Capability checks
  *
  * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  *
  * Author: Tom Lendacky <thomas.lendacky@amd.com>
  */
 
 #include <linux/export.h>
 #include <linux/cc_platform.h>
+#include <linux/string.h>
+#include <linux/random.h>
 
+#include <asm/archrandom.h>
 #include <asm/coco.h>
 #include <asm/processor.h>
 
@@ -148,3 +152,40 @@ u64 cc_mkdec(u64 val)
 	}
 }
 EXPORT_SYMBOL_GPL(cc_mkdec);
+
+__init void cc_random_init(void)
+{
+	/*
+	 * The seed is 32 bytes (in units of longs), which is 256 bits, which
+	 * is the security level that the RNG is targeting.
+	 */
+	unsigned long rng_seed[32 / sizeof(long)];
+	size_t i, longs;
+
+	if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+		return;
+
+	/*
+	 * Since the CoCo threat model includes the host, the only reliable
+	 * source of entropy that can be neither observed nor manipulated is
+	 * RDRAND. Usually, RDRAND failure is considered tolerable, but since
+	 * CoCo guests have no other unobservable source of entropy, it's
+	 * important to at least ensure the RNG gets some initial random seeds.
+	 */
+	for (i = 0; i < ARRAY_SIZE(rng_seed); i += longs) {
+		longs = arch_get_random_longs(&rng_seed[i], ARRAY_SIZE(rng_seed) - i);
+
+		/*
+		 * A zero return value means that the guest doesn't have RDRAND
+		 * or the CPU is physically broken, and in both cases that
+		 * means most crypto inside of the CoCo instance will be
+		 * broken, defeating the purpose of CoCo in the first place. So
+		 * just panic here because it's absolutely unsafe to continue
+		 * executing.
+		 */
+		if (longs == 0)
+			panic("RDRAND is defective.");
+	}
+	add_device_randomness(rng_seed, sizeof(rng_seed));
+	memzero_explicit(rng_seed, sizeof(rng_seed));
+}
diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c
index 78e4132697..1655aa56a0 100644
--- a/arch/x86/coco/tdx/tdx-shared.c
+++ b/arch/x86/coco/tdx/tdx-shared.c
@@ -22,13 +22,13 @@ static unsigned long try_accept_one(phys_addr_t start, unsigned long len,
 	 */
 	switch (pg_level) {
 	case PG_LEVEL_4K:
-		page_size = 0;
+		page_size = TDX_PS_4K;
 		break;
 	case PG_LEVEL_2M:
-		page_size = 1;
+		page_size = TDX_PS_2M;
 		break;
 	case PG_LEVEL_1G:
-		page_size = 2;
+		page_size = TDX_PS_1G;
 		break;
 	default:
 		return 0;
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index cf1f13c821..c1cb903699 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -887,7 +887,7 @@ void __init tdx_early_init(void)
 	 * there.
 	 *
 	 * Intel-TDX has a secure RDMSR hypercall, but that needs to be
-	 * implemented seperately in the low level startup ASM code.
+	 * implemented separately in the low level startup ASM code.
 	 * Until that is in place, disable parallel bringup for TDX.
 	 */
 	x86_cpuinit.parallel_bringup = false;