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Subject[PATCH v15 11/23] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs
Date
SGX defines its own CPUID leaf, 0x12, along with a variable number of
sub-leafs. Sub-leafs 0 and 1 are always available if SGX is supported
and enumerate various SGX features, e.g. instruction sets and enclave
capabilities. Sub-leafs 2+ are variable, both in their existence and
in what they enumerate. Bits 3:0 of EAX report the sub-leaf type,
with the remaining bits in EAX, EBX, ECX and EDX being type-specific.
Currently, the only known sub-leaf type enumerates an EPC section. An
EPC section is simply a range of EPC memory available to software.
The "list" of varaible SGX sub-leafs is NULL-terminated, i.e. software
is expected to query CPUID until an invalid sub-leaf is encountered.

Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
arch/x86/include/asm/sgx_arch.h | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/arch/x86/include/asm/sgx_arch.h b/arch/x86/include/asm/sgx_arch.h
index d4c57154e6e6..29c37971e8b3 100644
--- a/arch/x86/include/asm/sgx_arch.h
+++ b/arch/x86/include/asm/sgx_arch.h
@@ -11,6 +11,21 @@
#include <linux/types.h>
#include <uapi/asm/sgx_errno.h>

+#define SGX_CPUID 0x12
+#define SGX_CPUID_FIRST_VARIABLE_SUB_LEAF 2
+
+/**
+ * enum sgx_sub_leaf_types - SGX CPUID variable sub-leaf types
+ * %SGX_CPUID_SUB_LEAF_INVALID: Indicates this sub-leaf is invalid.
+ * %SGX_CPUID_SUB_LEAF_EPC_SECTION: Sub-leaf enumerates an EPC section.
+ * %SGX_CPUID_SUB_LEAF_TYPE_MASK: Mask for bits containing the type.
+ */
+enum sgx_sub_leaf_types {
+ SGX_CPUID_SUB_LEAF_INVALID = 0x0,
+ SGX_CPUID_SUB_LEAF_EPC_SECTION = 0x1,
+ SGX_CPUID_SUB_LEAF_TYPE_MASK = 0xF,
+};
+
/**
* enum sgx_encls_leaves - ENCLS leaf functions
* %SGX_ECREATE: Create an enclave.
--
2.19.1
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