[PATCH v7 076/120] x86/sgx/driver: Use parsed CPUID(0x12)

[Ahmed S. Darwish]

Use parsed CPUID(0x12).0 and CPUID(0x12).1 instead of doing bitwise
operations and direct CPUID queries.

Since SGX feature availablility mandates the existence of both
CPUID(0x12).0 and CPUID(0x12).1, exit the driver early in case any one of
them is not available.

Signed-off-by: Ahmed S. Darwish <darwi@xxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/sgx/driver.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index 9268289cd9f9..c5bc3f85ad97 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -165,32 +165,33 @@ static struct miscdevice sgx_dev_enclave = {
 
 int __init sgx_drv_init(void)
 {
-	unsigned int eax, ebx, ecx, edx;
+	const struct leaf_0x12_0 *l0 = cpuid_leaf(&boot_cpu_data, 0x12);
+	const struct cpuid_regs *l0r = cpuid_leaf_raw(&boot_cpu_data, 0x12);
+	const struct cpuid_regs *l1r = cpuid_subleaf_raw(&boot_cpu_data, 0x12, 1);
 	u64 attr_mask;
 	u64 xfrm_mask;
 	int ret;
 
+	if (!l0 || !l0r || !l1r)
+		return -ENODEV;
+
 	if (!cpu_feature_enabled(X86_FEATURE_SGX_LC)) {
 		pr_info("SGX disabled: SGX launch control CPU feature is not available, /dev/sgx_enclave disabled.\n");
 		return -ENODEV;
 	}
 
-	cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx);
-
-	if (!(eax & 1))  {
+	if (!l0->sgx1) {
 		pr_info("SGX disabled: SGX1 instruction support not available, /dev/sgx_enclave disabled.\n");
 		return -ENODEV;
 	}
 
-	sgx_misc_reserved_mask = ~ebx | SGX_MISC_RESERVED_MASK;
-
-	cpuid_count(SGX_CPUID, 1, &eax, &ebx, &ecx, &edx);
+	sgx_misc_reserved_mask = ~l0r->ebx | SGX_MISC_RESERVED_MASK;
 
-	attr_mask = (((u64)ebx) << 32) + (u64)eax;
+	attr_mask = (((u64)l1r->ebx) << 32) + (u64)l1r->eax;
 	sgx_attributes_reserved_mask = ~attr_mask | SGX_ATTR_RESERVED_MASK;
 
 	if (cpu_feature_enabled(X86_FEATURE_OSXSAVE)) {
-		xfrm_mask = (((u64)edx) << 32) + (u64)ecx;
+		xfrm_mask = (((u64)l1r->edx) << 32) + (u64)l1r->ecx;
 		sgx_xfrm_reserved_mask = ~xfrm_mask;
 	}
 
-- 
2.54.0