xref: /cloud-hypervisor/hypervisor/src/kvm/aarch64/mod.rs (revision 9af2968a7dc47b89bf07ea9dc5e735084efcfa3a)
1 // Copyright © 2019 Intel Corporation
2 //
3 // SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
4 //
5 // Copyright © 2020, Microsoft Corporation
6 //
7 // Copyright 2018-2019 CrowdStrike, Inc.
8 //
9 //
10 
11 ///
12 /// Export generically-named wrappers of kvm-bindings for Unix-based platforms
13 ///
14 use crate::kvm::{KvmError, KvmResult};
15 use kvm_bindings::{
16     kvm_mp_state, kvm_one_reg, kvm_regs, KVM_REG_ARM64, KVM_REG_ARM64_SYSREG,
17     KVM_REG_ARM64_SYSREG_CRM_MASK, KVM_REG_ARM64_SYSREG_CRM_SHIFT, KVM_REG_ARM64_SYSREG_CRN_MASK,
18     KVM_REG_ARM64_SYSREG_CRN_SHIFT, KVM_REG_ARM64_SYSREG_OP0_MASK, KVM_REG_ARM64_SYSREG_OP0_SHIFT,
19     KVM_REG_ARM64_SYSREG_OP1_MASK, KVM_REG_ARM64_SYSREG_OP1_SHIFT, KVM_REG_ARM64_SYSREG_OP2_MASK,
20     KVM_REG_ARM64_SYSREG_OP2_SHIFT, KVM_REG_ARM_COPROC_MASK, KVM_REG_ARM_CORE, KVM_REG_SIZE_MASK,
21     KVM_REG_SIZE_U32, KVM_REG_SIZE_U64,
22 };
23 pub use kvm_bindings::{
24     kvm_one_reg as Register, kvm_regs as StandardRegisters, kvm_vcpu_init as VcpuInit, RegList,
25 };
26 use serde_derive::{Deserialize, Serialize};
27 pub use {kvm_ioctls::Cap, kvm_ioctls::Kvm};
28 
29 // Following are macros that help with getting the ID of a aarch64 core register.
30 // The core register are represented by the user_pt_regs structure. Look for it in
31 // arch/arm64/include/uapi/asm/ptrace.h.
32 
33 // This macro gets the offset of a structure (i.e `str`) member (i.e `field`) without having
34 // an instance of that structure.
35 #[macro_export]
36 macro_rules! offset__of {
37     ($str:ty, $($field:ident)+) => ({
38         let tmp: std::mem::MaybeUninit<$str> = std::mem::MaybeUninit::uninit();
39         let tmp = unsafe { tmp.assume_init() };
40         let base = &tmp as *const _ as usize;
41         let member =  &tmp.$($field)* as *const _ as usize;
42 
43         member - base
44     });
45 }
46 // Get the ID of a core register
47 #[macro_export]
48 macro_rules! arm64_core_reg_id {
49     ($size: tt, $offset: tt) => {
50         // The core registers of an arm64 machine are represented
51         // in kernel by the `kvm_regs` structure. This structure is a
52         // mix of 32, 64 and 128 bit fields:
53         // struct kvm_regs {
54         //     struct user_pt_regs      regs;
55         //
56         //     __u64                    sp_el1;
57         //     __u64                    elr_el1;
58         //
59         //     __u64                    spsr[KVM_NR_SPSR];
60         //
61         //     struct user_fpsimd_state fp_regs;
62         // };
63         // struct user_pt_regs {
64         //     __u64 regs[31];
65         //     __u64 sp;
66         //     __u64 pc;
67         //     __u64 pstate;
68         // };
69         // The id of a core register can be obtained like this:
70         // offset = id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE). Thus,
71         // id = KVM_REG_ARM64 | KVM_REG_SIZE_U64/KVM_REG_SIZE_U32/KVM_REG_SIZE_U128 | KVM_REG_ARM_CORE | offset
72         KVM_REG_ARM64 as u64
73             | u64::from(KVM_REG_ARM_CORE)
74             | $size
75             | (($offset / mem::size_of::<u32>()) as u64)
76     };
77 }
78 
79 // This macro computes the ID of a specific ARM64 system register similar to how
80 // the kernel C macro does.
81 // https://elixir.bootlin.com/linux/v4.20.17/source/arch/arm64/include/uapi/asm/kvm.h#L203
82 #[macro_export]
83 macro_rules! arm64_sys_reg {
84     ($name: tt, $op0: tt, $op1: tt, $crn: tt, $crm: tt, $op2: tt) => {
85         pub const $name: u64 = KVM_REG_ARM64 as u64
86             | KVM_REG_SIZE_U64 as u64
87             | KVM_REG_ARM64_SYSREG as u64
88             | ((($op0 as u64) << KVM_REG_ARM64_SYSREG_OP0_SHIFT)
89                 & KVM_REG_ARM64_SYSREG_OP0_MASK as u64)
90             | ((($op1 as u64) << KVM_REG_ARM64_SYSREG_OP1_SHIFT)
91                 & KVM_REG_ARM64_SYSREG_OP1_MASK as u64)
92             | ((($crn as u64) << KVM_REG_ARM64_SYSREG_CRN_SHIFT)
93                 & KVM_REG_ARM64_SYSREG_CRN_MASK as u64)
94             | ((($crm as u64) << KVM_REG_ARM64_SYSREG_CRM_SHIFT)
95                 & KVM_REG_ARM64_SYSREG_CRM_MASK as u64)
96             | ((($op2 as u64) << KVM_REG_ARM64_SYSREG_OP2_SHIFT)
97                 & KVM_REG_ARM64_SYSREG_OP2_MASK as u64);
98     };
99 }
100 
101 // Constant imported from the Linux kernel:
102 // https://elixir.bootlin.com/linux/v4.20.17/source/arch/arm64/include/asm/sysreg.h#L135
103 arm64_sys_reg!(MPIDR_EL1, 3, 0, 0, 0, 5);
104 
105 /// Specifies whether a particular register is a system register or not.
106 /// The kernel splits the registers on aarch64 in core registers and system registers.
107 /// So, below we get the system registers by checking that they are not core registers.
108 ///
109 /// # Arguments
110 ///
111 /// * `regid` - The index of the register we are checking.
112 pub fn is_system_register(regid: u64) -> bool {
113     if (regid & KVM_REG_ARM_COPROC_MASK as u64) == KVM_REG_ARM_CORE as u64 {
114         return false;
115     }
116 
117     let size = regid & KVM_REG_SIZE_MASK;
118     if size != KVM_REG_SIZE_U32 && size != KVM_REG_SIZE_U64 {
119         panic!("Unexpected register size for system register {}", size);
120     }
121     true
122 }
123 
124 pub fn check_required_kvm_extensions(kvm: &Kvm) -> KvmResult<()> {
125     if !kvm.check_extension(Cap::SignalMsi) {
126         return Err(KvmError::CapabilityMissing(Cap::SignalMsi));
127     }
128     if !kvm.check_extension(Cap::OneReg) {
129         return Err(KvmError::CapabilityMissing(Cap::OneReg));
130     }
131     Ok(())
132 }
133 
134 #[derive(Clone, Default, Serialize, Deserialize)]
135 pub struct VcpuKvmState {
136     pub mp_state: kvm_mp_state,
137     pub core_regs: kvm_regs,
138     pub sys_regs: Vec<kvm_one_reg>,
139     // We will be using the mpidr for passing it to the VmState.
140     // The VmState will give this away for saving restoring the icc and redistributor
141     // registers.
142     pub mpidr: u64,
143 }
144