1 // SPDX-License-Identifier: GPL-2.0
2 
3 #define pr_fmt(fmt) "smccc: KVM: " fmt
4 
5 #include <linux/arm-smccc.h>
6 #include <linux/bitmap.h>
7 #include <linux/cache.h>
8 #include <linux/kernel.h>
9 #include <linux/string.h>
10 
11 #include <asm/hypervisor.h>
12 
13 static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_after_init = { };
14 
15 void __init kvm_init_hyp_services(void)
16 {
17 	struct arm_smccc_res res;
18 	u32 val[4];
19 
20 	if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC)
21 		return;
22 
23 	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
24 	if (res.a0 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 ||
25 	    res.a1 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 ||
26 	    res.a2 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 ||
27 	    res.a3 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3)
28 		return;
29 
30 	memset(&res, 0, sizeof(res));
31 	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID, &res);
32 
33 	val[0] = lower_32_bits(res.a0);
34 	val[1] = lower_32_bits(res.a1);
35 	val[2] = lower_32_bits(res.a2);
36 	val[3] = lower_32_bits(res.a3);
37 
38 	bitmap_from_arr32(__kvm_arm_hyp_services, val, ARM_SMCCC_KVM_NUM_FUNCS);
39 
40 	pr_info("hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n",
41 		 res.a3, res.a2, res.a1, res.a0);
42 }
43 
44 bool kvm_arm_hyp_service_available(u32 func_id)
45 {
46 	if (func_id >= ARM_SMCCC_KVM_NUM_FUNCS)
47 		return false;
48 
49 	return test_bit(func_id, __kvm_arm_hyp_services);
50 }
51 EXPORT_SYMBOL_GPL(kvm_arm_hyp_service_available);
52