xref: /openbmc/linux/arch/arm64/include/asm/kvm_asm.h (revision ed84ef1c)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2012,2013 - ARM Ltd
4  * Author: Marc Zyngier <marc.zyngier@arm.com>
5  */
6 
7 #ifndef __ARM_KVM_ASM_H__
8 #define __ARM_KVM_ASM_H__
9 
10 #include <asm/hyp_image.h>
11 #include <asm/insn.h>
12 #include <asm/virt.h>
13 
14 #define ARM_EXIT_WITH_SERROR_BIT  31
15 #define ARM_EXCEPTION_CODE(x)	  ((x) & ~(1U << ARM_EXIT_WITH_SERROR_BIT))
16 #define ARM_EXCEPTION_IS_TRAP(x)  (ARM_EXCEPTION_CODE((x)) == ARM_EXCEPTION_TRAP)
17 #define ARM_SERROR_PENDING(x)	  !!((x) & (1U << ARM_EXIT_WITH_SERROR_BIT))
18 
19 #define ARM_EXCEPTION_IRQ	  0
20 #define ARM_EXCEPTION_EL1_SERROR  1
21 #define ARM_EXCEPTION_TRAP	  2
22 #define ARM_EXCEPTION_IL	  3
23 /* The hyp-stub will return this for any kvm_call_hyp() call */
24 #define ARM_EXCEPTION_HYP_GONE	  HVC_STUB_ERR
25 
26 #define kvm_arm_exception_type					\
27 	{ARM_EXCEPTION_IRQ,		"IRQ"		},	\
28 	{ARM_EXCEPTION_EL1_SERROR, 	"SERROR"	},	\
29 	{ARM_EXCEPTION_TRAP, 		"TRAP"		},	\
30 	{ARM_EXCEPTION_HYP_GONE,	"HYP_GONE"	}
31 
32 /*
33  * Size of the HYP vectors preamble. kvm_patch_vector_branch() generates code
34  * that jumps over this.
35  */
36 #define KVM_VECTOR_PREAMBLE	(2 * AARCH64_INSN_SIZE)
37 
38 #define KVM_HOST_SMCCC_ID(id)						\
39 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
40 			   ARM_SMCCC_SMC_64,				\
41 			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
42 			   (id))
43 
44 #define KVM_HOST_SMCCC_FUNC(name) KVM_HOST_SMCCC_ID(__KVM_HOST_SMCCC_FUNC_##name)
45 
46 #define __KVM_HOST_SMCCC_FUNC___kvm_hyp_init			0
47 #define __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run			1
48 #define __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context		2
49 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa		3
50 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid		4
51 #define __KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context		5
52 #define __KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff		6
53 #define __KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs			7
54 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config		8
55 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr		9
56 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_write_vmcr		10
57 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs		11
58 #define __KVM_HOST_SMCCC_FUNC___kvm_get_mdcr_el2		12
59 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs		13
60 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs		14
61 #define __KVM_HOST_SMCCC_FUNC___pkvm_init			15
62 #define __KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp		16
63 #define __KVM_HOST_SMCCC_FUNC___pkvm_create_private_mapping	17
64 #define __KVM_HOST_SMCCC_FUNC___pkvm_cpu_set_vector		18
65 #define __KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize		19
66 #define __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc			20
67 
68 #ifndef __ASSEMBLY__
69 
70 #include <linux/mm.h>
71 
72 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]
73 #define DECLARE_KVM_NVHE_SYM(sym)	extern char kvm_nvhe_sym(sym)[]
74 
75 /*
76  * Define a pair of symbols sharing the same name but one defined in
77  * VHE and the other in nVHE hyp implementations.
78  */
79 #define DECLARE_KVM_HYP_SYM(sym)		\
80 	DECLARE_KVM_VHE_SYM(sym);		\
81 	DECLARE_KVM_NVHE_SYM(sym)
82 
83 #define DECLARE_KVM_VHE_PER_CPU(type, sym)	\
84 	DECLARE_PER_CPU(type, sym)
85 #define DECLARE_KVM_NVHE_PER_CPU(type, sym)	\
86 	DECLARE_PER_CPU(type, kvm_nvhe_sym(sym))
87 
88 #define DECLARE_KVM_HYP_PER_CPU(type, sym)	\
89 	DECLARE_KVM_VHE_PER_CPU(type, sym);	\
90 	DECLARE_KVM_NVHE_PER_CPU(type, sym)
91 
92 /*
93  * Compute pointer to a symbol defined in nVHE percpu region.
94  * Returns NULL if percpu memory has not been allocated yet.
95  */
96 #define this_cpu_ptr_nvhe_sym(sym)	per_cpu_ptr_nvhe_sym(sym, smp_processor_id())
97 #define per_cpu_ptr_nvhe_sym(sym, cpu)						\
98 	({									\
99 		unsigned long base, off;					\
100 		base = kvm_arm_hyp_percpu_base[cpu];				\
101 		off = (unsigned long)&CHOOSE_NVHE_SYM(sym) -			\
102 		      (unsigned long)&CHOOSE_NVHE_SYM(__per_cpu_start);		\
103 		base ? (typeof(CHOOSE_NVHE_SYM(sym))*)(base + off) : NULL;	\
104 	})
105 
106 #if defined(__KVM_NVHE_HYPERVISOR__)
107 
108 #define CHOOSE_NVHE_SYM(sym)	sym
109 #define CHOOSE_HYP_SYM(sym)	CHOOSE_NVHE_SYM(sym)
110 
111 /* The nVHE hypervisor shouldn't even try to access VHE symbols */
112 extern void *__nvhe_undefined_symbol;
113 #define CHOOSE_VHE_SYM(sym)		__nvhe_undefined_symbol
114 #define this_cpu_ptr_hyp_sym(sym)	(&__nvhe_undefined_symbol)
115 #define per_cpu_ptr_hyp_sym(sym, cpu)	(&__nvhe_undefined_symbol)
116 
117 #elif defined(__KVM_VHE_HYPERVISOR__)
118 
119 #define CHOOSE_VHE_SYM(sym)	sym
120 #define CHOOSE_HYP_SYM(sym)	CHOOSE_VHE_SYM(sym)
121 
122 /* The VHE hypervisor shouldn't even try to access nVHE symbols */
123 extern void *__vhe_undefined_symbol;
124 #define CHOOSE_NVHE_SYM(sym)		__vhe_undefined_symbol
125 #define this_cpu_ptr_hyp_sym(sym)	(&__vhe_undefined_symbol)
126 #define per_cpu_ptr_hyp_sym(sym, cpu)	(&__vhe_undefined_symbol)
127 
128 #else
129 
130 /*
131  * BIG FAT WARNINGS:
132  *
133  * - Don't be tempted to change the following is_kernel_in_hyp_mode()
134  *   to has_vhe(). has_vhe() is implemented as a *final* capability,
135  *   while this is used early at boot time, when the capabilities are
136  *   not final yet....
137  *
138  * - Don't let the nVHE hypervisor have access to this, as it will
139  *   pick the *wrong* symbol (yes, it runs at EL2...).
140  */
141 #define CHOOSE_HYP_SYM(sym)		(is_kernel_in_hyp_mode()	\
142 					   ? CHOOSE_VHE_SYM(sym)	\
143 					   : CHOOSE_NVHE_SYM(sym))
144 
145 #define this_cpu_ptr_hyp_sym(sym)	(is_kernel_in_hyp_mode()	\
146 					   ? this_cpu_ptr(&sym)		\
147 					   : this_cpu_ptr_nvhe_sym(sym))
148 
149 #define per_cpu_ptr_hyp_sym(sym, cpu)	(is_kernel_in_hyp_mode()	\
150 					   ? per_cpu_ptr(&sym, cpu)	\
151 					   : per_cpu_ptr_nvhe_sym(sym, cpu))
152 
153 #define CHOOSE_VHE_SYM(sym)	sym
154 #define CHOOSE_NVHE_SYM(sym)	kvm_nvhe_sym(sym)
155 
156 #endif
157 
158 struct kvm_nvhe_init_params {
159 	unsigned long mair_el2;
160 	unsigned long tcr_el2;
161 	unsigned long tpidr_el2;
162 	unsigned long stack_hyp_va;
163 	phys_addr_t pgd_pa;
164 	unsigned long hcr_el2;
165 	unsigned long vttbr;
166 	unsigned long vtcr;
167 };
168 
169 /* Translate a kernel address @ptr into its equivalent linear mapping */
170 #define kvm_ksym_ref(ptr)						\
171 	({								\
172 		void *val = (ptr);					\
173 		if (!is_kernel_in_hyp_mode())				\
174 			val = lm_alias((ptr));				\
175 		val;							\
176 	 })
177 #define kvm_ksym_ref_nvhe(sym)	kvm_ksym_ref(kvm_nvhe_sym(sym))
178 
179 struct kvm;
180 struct kvm_vcpu;
181 struct kvm_s2_mmu;
182 
183 DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
184 DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
185 #define __kvm_hyp_init		CHOOSE_NVHE_SYM(__kvm_hyp_init)
186 #define __kvm_hyp_vector	CHOOSE_HYP_SYM(__kvm_hyp_vector)
187 
188 extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
189 DECLARE_KVM_NVHE_SYM(__per_cpu_start);
190 DECLARE_KVM_NVHE_SYM(__per_cpu_end);
191 
192 DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
193 #define __bp_harden_hyp_vecs	CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
194 
195 extern void __kvm_flush_vm_context(void);
196 extern void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu);
197 extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
198 				     int level);
199 extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
200 
201 extern void __kvm_timer_set_cntvoff(u64 cntvoff);
202 
203 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
204 
205 extern void __kvm_adjust_pc(struct kvm_vcpu *vcpu);
206 
207 extern u64 __vgic_v3_get_gic_config(void);
208 extern u64 __vgic_v3_read_vmcr(void);
209 extern void __vgic_v3_write_vmcr(u32 vmcr);
210 extern void __vgic_v3_init_lrs(void);
211 
212 extern u64 __kvm_get_mdcr_el2(void);
213 
214 #define __KVM_EXTABLE(from, to)						\
215 	"	.pushsection	__kvm_ex_table, \"a\"\n"		\
216 	"	.align		3\n"					\
217 	"	.long		(" #from " - .), (" #to " - .)\n"	\
218 	"	.popsection\n"
219 
220 
221 #define __kvm_at(at_op, addr)						\
222 ( { 									\
223 	int __kvm_at_err = 0;						\
224 	u64 spsr, elr;							\
225 	asm volatile(							\
226 	"	mrs	%1, spsr_el2\n"					\
227 	"	mrs	%2, elr_el2\n"					\
228 	"1:	at	"at_op", %3\n"					\
229 	"	isb\n"							\
230 	"	b	9f\n"						\
231 	"2:	msr	spsr_el2, %1\n"					\
232 	"	msr	elr_el2, %2\n"					\
233 	"	mov	%w0, %4\n"					\
234 	"9:\n"								\
235 	__KVM_EXTABLE(1b, 2b)						\
236 	: "+r" (__kvm_at_err), "=&r" (spsr), "=&r" (elr)		\
237 	: "r" (addr), "i" (-EFAULT));					\
238 	__kvm_at_err;							\
239 } )
240 
241 
242 #else /* __ASSEMBLY__ */
243 
244 .macro get_host_ctxt reg, tmp
245 	adr_this_cpu \reg, kvm_host_data, \tmp
246 	add	\reg, \reg, #HOST_DATA_CONTEXT
247 .endm
248 
249 .macro get_vcpu_ptr vcpu, ctxt
250 	get_host_ctxt \ctxt, \vcpu
251 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
252 .endm
253 
254 .macro get_loaded_vcpu vcpu, ctxt
255 	adr_this_cpu \ctxt, kvm_hyp_ctxt, \vcpu
256 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
257 .endm
258 
259 .macro set_loaded_vcpu vcpu, ctxt, tmp
260 	adr_this_cpu \ctxt, kvm_hyp_ctxt, \tmp
261 	str	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
262 .endm
263 
264 /*
265  * KVM extable for unexpected exceptions.
266  * In the same format _asm_extable, but output to a different section so that
267  * it can be mapped to EL2. The KVM version is not sorted. The caller must
268  * ensure:
269  * x18 has the hypervisor value to allow any Shadow-Call-Stack instrumented
270  * code to write to it, and that SPSR_EL2 and ELR_EL2 are restored by the fixup.
271  */
272 .macro	_kvm_extable, from, to
273 	.pushsection	__kvm_ex_table, "a"
274 	.align		3
275 	.long		(\from - .), (\to - .)
276 	.popsection
277 .endm
278 
279 #define CPU_XREG_OFFSET(x)	(CPU_USER_PT_REGS + 8*x)
280 #define CPU_LR_OFFSET		CPU_XREG_OFFSET(30)
281 #define CPU_SP_EL0_OFFSET	(CPU_LR_OFFSET + 8)
282 
283 /*
284  * We treat x18 as callee-saved as the host may use it as a platform
285  * register (e.g. for shadow call stack).
286  */
287 .macro save_callee_saved_regs ctxt
288 	str	x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
289 	stp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
290 	stp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
291 	stp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
292 	stp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
293 	stp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
294 	stp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
295 .endm
296 
297 .macro restore_callee_saved_regs ctxt
298 	// We require \ctxt is not x18-x28
299 	ldr	x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
300 	ldp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
301 	ldp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
302 	ldp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
303 	ldp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
304 	ldp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
305 	ldp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
306 .endm
307 
308 .macro save_sp_el0 ctxt, tmp
309 	mrs	\tmp,	sp_el0
310 	str	\tmp,	[\ctxt, #CPU_SP_EL0_OFFSET]
311 .endm
312 
313 .macro restore_sp_el0 ctxt, tmp
314 	ldr	\tmp,	  [\ctxt, #CPU_SP_EL0_OFFSET]
315 	msr	sp_el0, \tmp
316 .endm
317 
318 #endif
319 
320 #endif /* __ARM_KVM_ASM_H__ */
321