drivers/firmware/smccc/kvm_guest.c

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