Merge tag 'x86_sgx_for_6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 sgx updates from Dave Hansen:
 "The biggest deal in this series is support for a new hardware feature
  that allows enclaves to detect and mitigate single-stepping attacks.

  There's also a minor performance tweak and a little piece of the
  kmap_atomic() -> kmap_local() transition.

  Summary:

   - Introduce a new SGX feature (Asynchrounous Exit Notification) for
     bare-metal enclaves and KVM guests to mitigate single-step attacks

   - Increase batching to speed up enclave release

   - Replace kmap/kunmap_atomic() calls"

* tag 'x86_sgx_for_6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sgx: Replace kmap/kunmap_atomic() calls
  KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest
  x86/sgx: Allow enclaves to use Asynchrounous Exit Notification
  x86/sgx: Reduce delay and interference of enclave release

3 files changed, 32 insertions, 17 deletions

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 1ec20807de1e..68f8b18d2278 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -160,8 +160,8 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
 		return ret;
 
 	pginfo.addr = encl_page->desc & PAGE_MASK;
-	pginfo.contents = (unsigned long)kmap_atomic(b.contents);
-	pcmd_page = kmap_atomic(b.pcmd);
+	pginfo.contents = (unsigned long)kmap_local_page(b.contents);
+	pcmd_page = kmap_local_page(b.pcmd);
 	pginfo.metadata = (unsigned long)pcmd_page + b.pcmd_offset;
 
 	if (secs_page)
@@ -187,8 +187,8 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
 	 */
 	pcmd_page_empty = !memchr_inv(pcmd_page, 0, PAGE_SIZE);
 
-	kunmap_atomic(pcmd_page);
-	kunmap_atomic((void *)(unsigned long)pginfo.contents);
+	kunmap_local(pcmd_page);
+	kunmap_local((void *)(unsigned long)pginfo.contents);
 
 	get_page(b.pcmd);
 	sgx_encl_put_backing(&b);
@@ -197,10 +197,10 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
 
 	if (pcmd_page_empty && !reclaimer_writing_to_pcmd(encl, pcmd_first_page)) {
 		sgx_encl_truncate_backing_page(encl, PFN_DOWN(page_pcmd_off));
-		pcmd_page = kmap_atomic(b.pcmd);
+		pcmd_page = kmap_local_page(b.pcmd);
 		if (memchr_inv(pcmd_page, 0, PAGE_SIZE))
 			pr_warn("PCMD page not empty after truncate.\n");
-		kunmap_atomic(pcmd_page);
+		kunmap_local(pcmd_page);
 	}
 
 	put_page(b.pcmd);
@@ -680,11 +680,15 @@ const struct vm_operations_struct sgx_vm_ops = {
 void sgx_encl_release(struct kref *ref)
 {
 	struct sgx_encl *encl = container_of(ref, struct sgx_encl, refcount);
+	unsigned long max_page_index = PFN_DOWN(encl->base + encl->size - 1);
 	struct sgx_va_page *va_page;
 	struct sgx_encl_page *entry;
-	unsigned long index;
+	unsigned long count = 0;
+
+	XA_STATE(xas, &encl->page_array, PFN_DOWN(encl->base));
 
-	xa_for_each(&encl->page_array, index, entry) {
+	xas_lock(&xas);
+	xas_for_each(&xas, entry, max_page_index) {
 		if (entry->epc_page) {
 			/*
 			 * The page and its radix tree entry cannot be freed
@@ -699,9 +703,20 @@ void sgx_encl_release(struct kref *ref)
 		}
 
 		kfree(entry);
-		/* Invoke scheduler to prevent soft lockups. */
-		cond_resched();
+		/*
+		 * Invoke scheduler on every XA_CHECK_SCHED iteration
+		 * to prevent soft lockups.
+		 */
+		if (!(++count % XA_CHECK_SCHED)) {
+			xas_pause(&xas);
+			xas_unlock(&xas);
+
+			cond_resched();
+
+			xas_lock(&xas);
+		}
 	}
+	xas_unlock(&xas);
 
 	xa_destroy(&encl->page_array);
 
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index da8b8ea6b063..21ca0a831b70 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -111,7 +111,7 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
 	encl->base = secs->base;
 	encl->size = secs->size;
 	encl->attributes = secs->attributes;
-	encl->attributes_mask = SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | SGX_ATTR_KSS;
+	encl->attributes_mask = SGX_ATTR_UNPRIV_MASK;
 
 	/* Set only after completion, as encl->lock has not been taken. */
 	set_bit(SGX_ENCL_CREATED, &encl->flags);
@@ -221,11 +221,11 @@ static int __sgx_encl_add_page(struct sgx_encl *encl,
 	pginfo.secs = (unsigned long)sgx_get_epc_virt_addr(encl->secs.epc_page);
 	pginfo.addr = encl_page->desc & PAGE_MASK;
 	pginfo.metadata = (unsigned long)secinfo;
-	pginfo.contents = (unsigned long)kmap_atomic(src_page);
+	pginfo.contents = (unsigned long)kmap_local_page(src_page);
 
 	ret = __eadd(&pginfo, sgx_get_epc_virt_addr(epc_page));
 
-	kunmap_atomic((void *)pginfo.contents);
+	kunmap_local((void *)pginfo.contents);
 	put_page(src_page);
 
 	return ret ? -EIO : 0;
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 0aad028f04d4..e5a37b6e9aa5 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -165,17 +165,17 @@ static int __sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot,
 	pginfo.addr = 0;
 	pginfo.secs = 0;
 
-	pginfo.contents = (unsigned long)kmap_atomic(backing->contents);
-	pginfo.metadata = (unsigned long)kmap_atomic(backing->pcmd) +
+	pginfo.contents = (unsigned long)kmap_local_page(backing->contents);
+	pginfo.metadata = (unsigned long)kmap_local_page(backing->pcmd) +
 			  backing->pcmd_offset;
 
 	ret = __ewb(&pginfo, sgx_get_epc_virt_addr(epc_page), va_slot);
 	set_page_dirty(backing->pcmd);
 	set_page_dirty(backing->contents);
 
-	kunmap_atomic((void *)(unsigned long)(pginfo.metadata -
+	kunmap_local((void *)(unsigned long)(pginfo.metadata -
 					      backing->pcmd_offset));
-	kunmap_atomic((void *)(unsigned long)pginfo.contents);
+	kunmap_local((void *)(unsigned long)pginfo.contents);
 
 	return ret;
 }