[RFC PATCH 20/21] x86/sgx: Export sgx_set_attribute() for use by KVM

[Sean Christopherson <sean.j.christopherson@intel.com>]

To prevent userspace from circumventing access to the PROVISIONKEY by
running an enclave in a VM, KVM will deny access to the PROVISIONKEY
unless userspace proves to KVM that it is allowed to access the key.
Export sgx_set_attribute() so that it may be used by KVM to verify an
SGX attribute file.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/include/asm/sgx.h             | 2 ++
 arch/x86/kernel/cpu/sgx/driver/ioctl.c | 1 +
 arch/x86/kernel/cpu/sgx/main.c         | 1 +
 arch/x86/kernel/cpu/sgx/sgx.h          | 1 -
 4 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
index f0f0176b8e2f..65c9417d3a80 100644
--- a/arch/x86/include/asm/sgx.h
+++ b/arch/x86/include/asm/sgx.h
@@ -6,6 +6,8 @@
 
 struct sgx_pageinfo;
 
+int sgx_set_attribute(u64 *allowed_attributes, unsigned int attribute_fd);
+
 #if IS_ENABLED(CONFIG_KVM_INTEL)
 int sgx_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs, int *trapnr);
 int sgx_einit(void __user *sigstruct, void __user *token,
diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
index a1cb5f772363..1b7a05cd9d02 100644
--- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
@@ -2,6 +2,7 @@
 // Copyright(c) 2016-19 Intel Corporation.
 
 #include <asm/mman.h>
+#include <asm/sgx.h>
 #include <linux/mman.h>
 #include <linux/delay.h>
 #include <linux/file.h>
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 542427c6ae9c..68e5c704378a 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -336,6 +336,7 @@ int sgx_set_attribute(u64 *allowed_attributes, unsigned int attribute_fd)
 	*allowed_attributes |= SGX_ATTR_PROVISIONKEY;
 	return 0;
 }
+EXPORT_SYMBOL_GPL(sgx_set_attribute);
 
 static void sgx_dev_release(struct device *dev)
 {
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index 3f3311024bd0..fab12cc0e7c5 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -96,6 +96,5 @@ void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce);
 __init int sgx_dev_init(const char *name, struct device *dev,
 			struct cdev *cdev, const struct file_operations *fops,
 			int minor);
-int sgx_set_attribute(u64 *allowed_attributes, unsigned int attribute_fd);
 
 #endif /* _X86_SGX_H */
-- 
2.22.0