xref: /cloud-hypervisor/hypervisor/src/kvm/aarch64/mod.rs (revision b440cb7d2330770cd415b63544a371d4caa2db3a)
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 pub mod gic;
12 
13 use crate::kvm::{KvmError, KvmResult};
14 use kvm_bindings::{
15     kvm_mp_state, kvm_one_reg, kvm_regs, KVM_REG_ARM64, KVM_REG_ARM64_SYSREG,
16     KVM_REG_ARM64_SYSREG_CRM_MASK, KVM_REG_ARM64_SYSREG_CRM_SHIFT, KVM_REG_ARM64_SYSREG_CRN_MASK,
17     KVM_REG_ARM64_SYSREG_CRN_SHIFT, KVM_REG_ARM64_SYSREG_OP0_MASK, KVM_REG_ARM64_SYSREG_OP0_SHIFT,
18     KVM_REG_ARM64_SYSREG_OP1_MASK, KVM_REG_ARM64_SYSREG_OP1_SHIFT, KVM_REG_ARM64_SYSREG_OP2_MASK,
19     KVM_REG_ARM64_SYSREG_OP2_SHIFT, KVM_REG_ARM_COPROC_MASK, KVM_REG_ARM_CORE, KVM_REG_SIZE_MASK,
20     KVM_REG_SIZE_U32, KVM_REG_SIZE_U64,
21 };
22 pub use kvm_bindings::{
23     kvm_one_reg as Register, kvm_regs as StandardRegisters, kvm_vcpu_init as VcpuInit, RegList,
24 };
25 use serde::{Deserialize, Serialize};
26 pub use {kvm_ioctls::Cap, kvm_ioctls::Kvm};
27 
28 // This macro gets the offset of a structure (i.e `str`) member (i.e `field`) without having
29 // an instance of that structure.
30 #[macro_export]
31 macro_rules! offset__of {
32     ($str:ty, $($field:ident)+) => ({
33         let tmp: std::mem::MaybeUninit<$str> = std::mem::MaybeUninit::uninit();
34         let base = tmp.as_ptr();
35 
36         // Avoid warnings when nesting `unsafe` blocks.
37         #[allow(unused_unsafe)]
38         // SAFETY: The pointer is valid and aligned, just not initialised. Using `addr_of` ensures
39         // that we don't actually read from `base` (which would be UB) nor create an intermediate
40         // reference.
41         let member = unsafe { core::ptr::addr_of!((*base).$($field)*) } as *const u8;
42 
43         // Avoid warnings when nesting `unsafe` blocks.
44         #[allow(unused_unsafe)]
45         // SAFETY: The two pointers are within the same allocated object `tmp`. All requirements
46         // from offset_from are upheld.
47         unsafe { member.offset_from(base as *const u8) as usize }
48     });
49 }
50 
51 // Following are macros that help with getting the ID of a aarch64 core register.
52 // The core register are represented by the user_pt_regs structure. Look for it in
53 // arch/arm64/include/uapi/asm/ptrace.h.
54 
55 // Get the ID of a core register
56 #[macro_export]
57 macro_rules! arm64_core_reg_id {
58     ($size: tt, $offset: tt) => {
59         // The core registers of an arm64 machine are represented
60         // in kernel by the `kvm_regs` structure. This structure is a
61         // mix of 32, 64 and 128 bit fields:
62         // struct kvm_regs {
63         //     struct user_pt_regs      regs;
64         //
65         //     __u64                    sp_el1;
66         //     __u64                    elr_el1;
67         //
68         //     __u64                    spsr[KVM_NR_SPSR];
69         //
70         //     struct user_fpsimd_state fp_regs;
71         // };
72         // struct user_pt_regs {
73         //     __u64 regs[31];
74         //     __u64 sp;
75         //     __u64 pc;
76         //     __u64 pstate;
77         // };
78         // The id of a core register can be obtained like this:
79         // offset = id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE). Thus,
80         // id = KVM_REG_ARM64 | KVM_REG_SIZE_U64/KVM_REG_SIZE_U32/KVM_REG_SIZE_U128 | KVM_REG_ARM_CORE | offset
81         KVM_REG_ARM64 as u64
82             | u64::from(KVM_REG_ARM_CORE)
83             | $size
84             | (($offset / mem::size_of::<u32>()) as u64)
85     };
86 }
87 
88 // This macro computes the ID of a specific ARM64 system register similar to how
89 // the kernel C macro does.
90 // https://elixir.bootlin.com/linux/v4.20.17/source/arch/arm64/include/uapi/asm/kvm.h#L203
91 #[macro_export]
92 macro_rules! arm64_sys_reg {
93     ($name: tt, $op0: tt, $op1: tt, $crn: tt, $crm: tt, $op2: tt) => {
94         pub const $name: u64 = KVM_REG_ARM64 as u64
95             | KVM_REG_SIZE_U64 as u64
96             | KVM_REG_ARM64_SYSREG as u64
97             | ((($op0 as u64) << KVM_REG_ARM64_SYSREG_OP0_SHIFT)
98                 & KVM_REG_ARM64_SYSREG_OP0_MASK as u64)
99             | ((($op1 as u64) << KVM_REG_ARM64_SYSREG_OP1_SHIFT)
100                 & KVM_REG_ARM64_SYSREG_OP1_MASK as u64)
101             | ((($crn as u64) << KVM_REG_ARM64_SYSREG_CRN_SHIFT)
102                 & KVM_REG_ARM64_SYSREG_CRN_MASK as u64)
103             | ((($crm as u64) << KVM_REG_ARM64_SYSREG_CRM_SHIFT)
104                 & KVM_REG_ARM64_SYSREG_CRM_MASK as u64)
105             | ((($op2 as u64) << KVM_REG_ARM64_SYSREG_OP2_SHIFT)
106                 & KVM_REG_ARM64_SYSREG_OP2_MASK as u64);
107     };
108 }
109 
110 // Constant imported from the Linux kernel:
111 // https://elixir.bootlin.com/linux/v4.20.17/source/arch/arm64/include/asm/sysreg.h#L135
112 arm64_sys_reg!(MPIDR_EL1, 3, 0, 0, 0, 5);
113 
114 /// Specifies whether a particular register is a system register or not.
115 /// The kernel splits the registers on aarch64 in core registers and system registers.
116 /// So, below we get the system registers by checking that they are not core registers.
117 ///
118 /// # Arguments
119 ///
120 /// * `regid` - The index of the register we are checking.
121 pub fn is_system_register(regid: u64) -> bool {
122     if (regid & KVM_REG_ARM_COPROC_MASK as u64) == KVM_REG_ARM_CORE as u64 {
123         return false;
124     }
125 
126     let size = regid & KVM_REG_SIZE_MASK;
127 
128     assert!(
129         !(size != KVM_REG_SIZE_U32 && size != KVM_REG_SIZE_U64),
130         "Unexpected register size for system register {}",
131         size
132     );
133 
134     true
135 }
136 
137 pub fn check_required_kvm_extensions(kvm: &Kvm) -> KvmResult<()> {
138     if !kvm.check_extension(Cap::SignalMsi) {
139         return Err(KvmError::CapabilityMissing(Cap::SignalMsi));
140     }
141     if !kvm.check_extension(Cap::OneReg) {
142         return Err(KvmError::CapabilityMissing(Cap::OneReg));
143     }
144     Ok(())
145 }
146 
147 #[derive(Clone, Default, Serialize, Deserialize)]
148 pub struct VcpuKvmState {
149     pub mp_state: kvm_mp_state,
150     pub core_regs: kvm_regs,
151     pub sys_regs: Vec<kvm_one_reg>,
152     // We will be using the mpidr for passing it to the VmState.
153     // The VmState will give this away for saving restoring the icc and redistributor
154     // registers.
155     pub mpidr: u64,
156 }
157