rune/libenclave/skeleton: xfrm should be a subset of xcr0 in different machine

Xfrm needs support the same xsave feature in encalve as in OS.
By cpuid, it can get the same value between xfrm and xcr0.
Signed-off-by: NLiang Yang <liang3.yang@intel.com>
Reviewed-by: Jia Zhang <zhang.jia@linux.alibaba.com>

rune/libenclave/internal/runtime/pal/skeleton/Makefile

@@ -24,13 +24,13 @@ endif
 
 all: $(TEST_CUSTOM_PROGS)
 
-$(OUTPUT)/liberpal-skeleton-v1.so: $(OUTPUT)/sgx_call.o $(OUTPUT)/liberpal-skeleton-v1.o $(OUTPUT)/liberpal-skeleton.o
+$(OUTPUT)/liberpal-skeleton-v1.so: $(OUTPUT)/sgx_call.o $(OUTPUT)/liberpal-skeleton-v1.o $(OUTPUT)/liberpal-skeleton.o $(OUTPUT)/sgxutils.o
 	$(CC) $(HOST_LDFLAGS) -o $@ $^
 
 $(OUTPUT)/liberpal-skeleton-v1.o: liberpal-skeleton-v1.c liberpal-skeleton.c
 	$(CC) $(HOST_CFLAGS) -c $< -o $@
 
-$(OUTPUT)/liberpal-skeleton-v2.so: $(OUTPUT)/sgx_call.o $(OUTPUT)/liberpal-skeleton-v2.o $(OUTPUT)/liberpal-skeleton.o
+$(OUTPUT)/liberpal-skeleton-v2.so: $(OUTPUT)/sgx_call.o $(OUTPUT)/liberpal-skeleton-v2.o $(OUTPUT)/liberpal-skeleton.o $(OUTPUT)/sgxutils.o
 	$(CC) $(HOST_LDFLAGS) -o $@ $^
 
 $(OUTPUT)/liberpal-skeleton-v2.o: liberpal-skeleton-v2.c liberpal-skeleton.c
@@ -39,7 +39,7 @@ $(OUTPUT)/liberpal-skeleton-v2.o: liberpal-skeleton-v2.c liberpal-skeleton.c
 $(OUTPUT)/liberpal-skeleton.o: liberpal-skeleton.c
 	$(CC) $(HOST_CFLAGS) -c $< -o $@
 
-$(OUTPUT)/liberpal-skeleton-v3.so: $(OUTPUT)/sgx_call.o $(OUTPUT)/liberpal-skeleton-v3.o $(OUTPUT)/liberpal-skeleton.o
+$(OUTPUT)/liberpal-skeleton-v3.so: $(OUTPUT)/sgx_call.o $(OUTPUT)/liberpal-skeleton-v3.o $(OUTPUT)/liberpal-skeleton.o $(OUTPUT)/sgxutils.o
 	$(CC) $(HOST_LDFLAGS) -o $@ $^
 
 $(OUTPUT)/liberpal-skeleton-v3.o: liberpal-skeleton-v3.c liberpal-skeleton.c
@@ -48,6 +48,9 @@ $(OUTPUT)/liberpal-skeleton-v3.o: liberpal-skeleton-v3.c liberpal-skeleton.c
 $(OUTPUT)/sgx_call.o: sgx_call.S
 	$(CC) $(HOST_CFLAGS) -c $< -o $@
 
+$(OUTPUT)/sgxutils.o: sgxutils.c
+	$(CC) $(HOST_CFLAGS) -c $< -o $@
+
 $(OUTPUT)/encl.bin: $(OUTPUT)/encl.elf $(OUTPUT)/sgxsign
 	$(OBJCOPY) -O binary $< $@
 
@@ -70,14 +73,15 @@ $(OUTPUT)/encl.ss: $(OUTPUT)/encl.bin $(OUTPUT)/signing_key.pem
 $(OUTPUT)/encl.token: $(OUTPUT)/encl.ss
 	sgx-tools gen-token --signature encl.ss --token $@
 
-$(OUTPUT)/sgxsign: sgxsign.c
-	$(CC) -I../include -o $@ $< -lcrypto
+$(OUTPUT)/sgxsign: sgxsign.c sgxutils.c
+	$(CC) -I../include -o $@ $^ -lcrypto
 
 EXTRA_CLEAN := \
 	$(OUTPUT)/encl.bin \
 	$(OUTPUT)/encl.elf \
 	$(OUTPUT)/encl.ss \
 	$(OUTPUT)/sgx_call.o \
+	$(OUTPUT)/sgxutils.o \
 	$(OUTPUT)/sgxsign \
 	$(OUTPUT)/liberpal-skeleton*.o \
 	$(OUTPUT)/liberpal-skeleton*.so \

rune/libenclave/internal/runtime/pal/skeleton/liberpal-skeleton.c

@@ -114,13 +114,16 @@ static bool encl_create(int dev_fd, unsigned long bin_size,
 {
 	struct sgx_enclave_create ioc;
 	int rc;
+	uint64_t xfrm;
 
 	memset(secs, 0, sizeof(*secs));
 	secs->ssa_frame_size = 1;
 	secs->attributes = SGX_ATTR_MODE64BIT;
 	if (enclave_debug)
 		secs->attributes |= SGX_ATTR_DEBUG;
-	secs->xfrm = 7;
+
+	get_sgx_xfrm_by_cpuid(&xfrm);
+	secs->xfrm = xfrm;
 
 	for (secs->size = PAGE_SIZE; secs->size < bin_size; )
 		secs->size <<= 1;

rune/libenclave/internal/runtime/pal/skeleton/sgx.h

@@ -17,6 +17,25 @@ enum sgx_page_flags {
 	SGX_PAGE_MEASURE	= 0x01,
 };
 
+#define	SGX_LEAF	0x12
+
+/**
+ *CPUID function 1
+ *ECX[26] enums general support for XSAVE
+ *ECX[27] enums XSAVE is enabled or not
+*/
+#define	XSAVE_SHIFT	26
+#define	OSXSAVE_SHIFT	27
+
+/**
+ *CPUID function 0DH, sub-function 1
+ *EAX[1] enums support for compaction extensions to XSAVE
+ */
+#define	XSAVEC_SHIFT	1
+
+/* XSAVE Feature Request Mask */
+#define	SGX_XFRM_LEGACY	0x0000000000000003ULL     /* Legacy XFRM which includes the basic feature bits required by SGX, x87 state(0x01) and SSE state(0x02) */
+
 #define SGX_MAGIC 0xA4
 
 #define SGX_IOC_ENCLAVE_CREATE \
@@ -143,4 +162,5 @@ typedef int (*sgx_enclave_exit_handler_t)(long rdi, long rsi, long rdx,
 					  void *tcs, int ret,
 					  struct sgx_enclave_exception *e);
 
+void get_sgx_xfrm_by_cpuid(uint64_t *xfrm);
 #endif /* _UAPI_ASM_X86_SGX_H */

rune/libenclave/internal/runtime/pal/skeleton/sgxsign.c

@@ -422,6 +422,7 @@ int main(int argc, char **argv)
 {
 	uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000};
 	uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060};
+	uint64_t xfrm;
 	struct sgx_sigstruct ss;
 	const char *program;
 	int opt;
@@ -465,7 +466,10 @@ int main(int argc, char **argv)
 #endif
 	if (enclave_debug)
 		ss.body.attributes |= SGX_ATTR_DEBUG;
-	ss.body.xfrm = 7;
+
+	get_sgx_xfrm_by_cpuid(&xfrm);
+	ss.body.xfrm = xfrm;
+
 	ss.body.attributes_mask = ss.body.attributes;
 
 	/* sanity check only */

rune/libenclave/internal/runtime/pal/skeleton/sgxutils.c

+#include <unistd.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include "sgx.h"
+
+static inline void cpuid(int *eax, int *ebx, int *ecx, int *edx)
+{
+#if defined(__x86_64__)
+	asm volatile ("cpuid"
+		: "=a" (*eax),
+		"=b" (*ebx),
+		"=c" (*ecx),
+		"=d" (*edx)
+		: "0" (*eax), "2" (*ecx)
+		: "memory");
+#else
+	/*on 32bit, ebx can NOT be used as PIC code*/
+	asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1"
+		: "=a" (*eax), "=r" (*ebx), "=c" (*ecx), "=d" (*edx)
+		: "0" (*eax), "2" (*ecx)
+		: "memory");
+#endif
+}
+
+static inline void __cpuid(int a[4], int b)
+{
+    a[0] = b;
+    a[2] = 0;
+    cpuid(&a[0], &a[1], &a[2], &a[3]);
+}
+
+static inline void __cpuidex(int a[4], int b, int c)
+{
+    a[0] = b;
+    a[2] = c;
+    cpuid(&a[0], &a[1], &a[2], &a[3]);
+}
+
+static inline uint64_t xgetbv(uint32_t index)
+{
+    uint32_t eax, edx;
+
+    asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */
+		: "=a" (eax), "=d" (edx)
+		: "c" (index));
+
+    return eax + ((uint64_t)edx << 32);
+}
+
+static inline uint64_t get_xcr0()
+{
+    return xgetbv(0);
+}
+
+static bool try_get_xcr0(uint64_t *value)
+{
+    int cpu_info[4] = {0, 0, 0, 0};
+
+    *value = SGX_XFRM_LEGACY;
+
+    // check if xgetbv instruction is supported
+    __cpuid(cpu_info, 1);
+    // ecx[27:26] indicate whether support xsave/xrstor, and whether enable xgetbv, xsetbv
+    if (!(cpu_info[2] & (1<<XSAVE_SHIFT)) || !(cpu_info[2] & (1<<OSXSAVE_SHIFT)))
+        return false;
+
+    *value = get_xcr0();
+
+    // check if xsavec is supported
+    // Assume that XSAVEC is always supported if XSAVE is supported
+    cpu_info[0] = cpu_info[1] = cpu_info[2] = cpu_info[3] = 0;
+    __cpuidex(cpu_info, 0xD, 1);
+    if (!(cpu_info[0] & (1<<XSAVEC_SHIFT)))
+        return false;
+
+    return true;
+}
+
+void get_sgx_xfrm_by_cpuid(uint64_t *xfrm)
+{
+    int cpu_info[4] = {0, 0, 0, 0};
+
+    __cpuidex(cpu_info, SGX_LEAF, 1);
+
+    if (false == try_get_xcr0(xfrm))
+    {
+	// if XSAVE is supported, while XSAVEC is not supported,
+	// set xfrm to legacy, because XSAVEC cannot be executed within enclave.
+	*xfrm = SGX_XFRM_LEGACY;
+    } else {
+	// If x-feature is supported and enabled by OS, we need make sure it is also supported in enclave.
+	*xfrm &= (((uint64_t)cpu_info[3] << 32) | cpu_info[2]);
+    }
+}