Merge tag 'x86_sgx_for_6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

bbd9c366 · Linus Torvalds <[email protected]> · 2025-05-29 21:13:17 -07:00

Pull Intel software guard extension (SGX) updates from Dave Hansen:
 "A couple of x86/sgx changes.

  The first one is a no-brainer to use the (simple) SHA-256 library.

  For the second one, some folks doing testing noticed that SGX systems
  under memory pressure were inducing fatal machine checks at pretty
  unnerving rates, despite the SGX code having _some_ awareness of
  memory poison.

  It turns out that the SGX reclaim path was not checking for poison
  _and_ it always accesses memory to copy it around. Make sure that
  poisoned pages are not reclaimed"

* tag 'x86_sgx_for_6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sgx: Prevent attempts to reclaim poisoned pages
  x86/sgx: Use SHA-256 library API instead of crypto_shash API

Commit: bbd9c366bfb2723435e82717ebbb3398f93a1f63
Parents: b78f1293 · ed16618c

Merge commit. Changes below are compared with the first parent: b78f1293.

Changes

4 files changed · +5 −31

File	Status	Add	Del	Content
arch/x86/Kconfig	modified	+1	−2	View file
arch/x86/kernel/cpu/sgx/driver.h	modified	+0	−1	View file
arch/x86/kernel/cpu/sgx/ioctl.c	modified	+2	−28	View file
arch/x86/kernel/cpu/sgx/main.c	modified	+2	−0	View file

arch/x86/Kconfig

View file

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0be4937..ae16542 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1858,8 +1858,7 @@ endchoice
 config X86_SGX
 	bool "Software Guard eXtensions (SGX)"
 	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
-	depends on CRYPTO=y
-	depends on CRYPTO_SHA256=y
+	select CRYPTO_LIB_SHA256
 	select MMU_NOTIFIER
 	select NUMA_KEEP_MEMINFO if NUMA
 	select XARRAY_MULTI

arch/x86/kernel/cpu/sgx/driver.h

View file

diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
index 4eddb4d..30f39f9 100644
--- a/arch/x86/kernel/cpu/sgx/driver.h
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -2,7 +2,6 @@
 #ifndef __ARCH_SGX_DRIVER_H__
 #define __ARCH_SGX_DRIVER_H__
 
-#include <crypto/hash.h>
 #include <linux/kref.h>
 #include <linux/mmu_notifier.h>
 #include <linux/radix-tree.h>

arch/x86/kernel/cpu/sgx/ioctl.c

View file

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 776a201..66f1efa 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -3,6 +3,7 @@
 
 #include <asm/mman.h>
 #include <asm/sgx.h>
+#include <crypto/sha2.h>
 #include <linux/mman.h>
 #include <linux/delay.h>
 #include <linux/file.h>
@@ -463,31 +464,6 @@ static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
 	return ret;
 }
 
-static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
-			      void *hash)
-{
-	SHASH_DESC_ON_STACK(shash, tfm);
-
-	shash->tfm = tfm;
-
-	return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
-}
-
-static int sgx_get_key_hash(const void *modulus, void *hash)
-{
-	struct crypto_shash *tfm;
-	int ret;
-
-	tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
-	if (IS_ERR(tfm))
-		return PTR_ERR(tfm);
-
-	ret = __sgx_get_key_hash(tfm, modulus, hash);
-
-	crypto_free_shash(tfm);
-	return ret;
-}
-
 static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
 			 void *token)
 {
@@ -523,9 +499,7 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
 	    sgx_xfrm_reserved_mask)
 		return -EINVAL;
 
-	ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
-	if (ret)
-		return ret;
+	sha256(sigstruct->modulus, SGX_MODULUS_SIZE, (u8 *)mrsigner);
 
 	mutex_lock(&encl->lock);
 

arch/x86/kernel/cpu/sgx/main.c

View file

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 6722b2f..2de01b3 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -720,6 +720,8 @@ int arch_memory_failure(unsigned long pfn, int flags)
 		goto out;
 	}
 
+	sgx_unmark_page_reclaimable(page);
+
 	/*
 	 * TBD: Add additional plumbing to enable pre-emptive
 	 * action for asynchronous poison notification. Until