xref: /linux/arch/arm64/include/asm/kvm_asm.h (revision 6562c9acb43ac69ba5a956b0c3911b883d90541f)
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 
48 #ifndef __ASSEMBLY__
49 
50 #include <linux/mm.h>
51 
52 enum __kvm_host_smccc_func {
53 	/* Hypercalls available only prior to pKVM finalisation */
54 	/* __KVM_HOST_SMCCC_FUNC___kvm_hyp_init */
55 	__KVM_HOST_SMCCC_FUNC___kvm_get_mdcr_el2 = __KVM_HOST_SMCCC_FUNC___kvm_hyp_init + 1,
56 	__KVM_HOST_SMCCC_FUNC___pkvm_init,
57 	__KVM_HOST_SMCCC_FUNC___pkvm_create_private_mapping,
58 	__KVM_HOST_SMCCC_FUNC___pkvm_cpu_set_vector,
59 	__KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs,
60 	__KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs,
61 	__KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config,
62 	__KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize,
63 
64 	/* Hypercalls available after pKVM finalisation */
65 	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp,
66 	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp,
67 	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
68 	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
69 	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
70 	__KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa,
71 	__KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid,
72 	__KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context,
73 	__KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff,
74 	__KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr,
75 	__KVM_HOST_SMCCC_FUNC___vgic_v3_write_vmcr,
76 	__KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs,
77 	__KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs,
78 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_init_traps,
79 };
80 
81 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]
82 #define DECLARE_KVM_NVHE_SYM(sym)	extern char kvm_nvhe_sym(sym)[]
83 
84 /*
85  * Define a pair of symbols sharing the same name but one defined in
86  * VHE and the other in nVHE hyp implementations.
87  */
88 #define DECLARE_KVM_HYP_SYM(sym)		\
89 	DECLARE_KVM_VHE_SYM(sym);		\
90 	DECLARE_KVM_NVHE_SYM(sym)
91 
92 #define DECLARE_KVM_VHE_PER_CPU(type, sym)	\
93 	DECLARE_PER_CPU(type, sym)
94 #define DECLARE_KVM_NVHE_PER_CPU(type, sym)	\
95 	DECLARE_PER_CPU(type, kvm_nvhe_sym(sym))
96 
97 #define DECLARE_KVM_HYP_PER_CPU(type, sym)	\
98 	DECLARE_KVM_VHE_PER_CPU(type, sym);	\
99 	DECLARE_KVM_NVHE_PER_CPU(type, sym)
100 
101 /*
102  * Compute pointer to a symbol defined in nVHE percpu region.
103  * Returns NULL if percpu memory has not been allocated yet.
104  */
105 #define this_cpu_ptr_nvhe_sym(sym)	per_cpu_ptr_nvhe_sym(sym, smp_processor_id())
106 #define per_cpu_ptr_nvhe_sym(sym, cpu)						\
107 	({									\
108 		unsigned long base, off;					\
109 		base = kvm_arm_hyp_percpu_base[cpu];				\
110 		off = (unsigned long)&CHOOSE_NVHE_SYM(sym) -			\
111 		      (unsigned long)&CHOOSE_NVHE_SYM(__per_cpu_start);		\
112 		base ? (typeof(CHOOSE_NVHE_SYM(sym))*)(base + off) : NULL;	\
113 	})
114 
115 #if defined(__KVM_NVHE_HYPERVISOR__)
116 
117 #define CHOOSE_NVHE_SYM(sym)	sym
118 #define CHOOSE_HYP_SYM(sym)	CHOOSE_NVHE_SYM(sym)
119 
120 /* The nVHE hypervisor shouldn't even try to access VHE symbols */
121 extern void *__nvhe_undefined_symbol;
122 #define CHOOSE_VHE_SYM(sym)		__nvhe_undefined_symbol
123 #define this_cpu_ptr_hyp_sym(sym)	(&__nvhe_undefined_symbol)
124 #define per_cpu_ptr_hyp_sym(sym, cpu)	(&__nvhe_undefined_symbol)
125 
126 #elif defined(__KVM_VHE_HYPERVISOR__)
127 
128 #define CHOOSE_VHE_SYM(sym)	sym
129 #define CHOOSE_HYP_SYM(sym)	CHOOSE_VHE_SYM(sym)
130 
131 /* The VHE hypervisor shouldn't even try to access nVHE symbols */
132 extern void *__vhe_undefined_symbol;
133 #define CHOOSE_NVHE_SYM(sym)		__vhe_undefined_symbol
134 #define this_cpu_ptr_hyp_sym(sym)	(&__vhe_undefined_symbol)
135 #define per_cpu_ptr_hyp_sym(sym, cpu)	(&__vhe_undefined_symbol)
136 
137 #else
138 
139 /*
140  * BIG FAT WARNINGS:
141  *
142  * - Don't be tempted to change the following is_kernel_in_hyp_mode()
143  *   to has_vhe(). has_vhe() is implemented as a *final* capability,
144  *   while this is used early at boot time, when the capabilities are
145  *   not final yet....
146  *
147  * - Don't let the nVHE hypervisor have access to this, as it will
148  *   pick the *wrong* symbol (yes, it runs at EL2...).
149  */
150 #define CHOOSE_HYP_SYM(sym)		(is_kernel_in_hyp_mode()	\
151 					   ? CHOOSE_VHE_SYM(sym)	\
152 					   : CHOOSE_NVHE_SYM(sym))
153 
154 #define this_cpu_ptr_hyp_sym(sym)	(is_kernel_in_hyp_mode()	\
155 					   ? this_cpu_ptr(&sym)		\
156 					   : this_cpu_ptr_nvhe_sym(sym))
157 
158 #define per_cpu_ptr_hyp_sym(sym, cpu)	(is_kernel_in_hyp_mode()	\
159 					   ? per_cpu_ptr(&sym, cpu)	\
160 					   : per_cpu_ptr_nvhe_sym(sym, cpu))
161 
162 #define CHOOSE_VHE_SYM(sym)	sym
163 #define CHOOSE_NVHE_SYM(sym)	kvm_nvhe_sym(sym)
164 
165 #endif
166 
167 struct kvm_nvhe_init_params {
168 	unsigned long mair_el2;
169 	unsigned long tcr_el2;
170 	unsigned long tpidr_el2;
171 	unsigned long stack_hyp_va;
172 	unsigned long stack_pa;
173 	phys_addr_t pgd_pa;
174 	unsigned long hcr_el2;
175 	unsigned long vttbr;
176 	unsigned long vtcr;
177 };
178 
179 /*
180  * Used by the host in EL1 to dump the nVHE hypervisor backtrace on
181  * hyp_panic() in non-protected mode.
182  *
183  * @stack_base:                 hyp VA of the hyp_stack base.
184  * @overflow_stack_base:        hyp VA of the hyp_overflow_stack base.
185  * @fp:                         hyp FP where the backtrace begins.
186  * @pc:                         hyp PC where the backtrace begins.
187  */
188 struct kvm_nvhe_stacktrace_info {
189 	unsigned long stack_base;
190 	unsigned long overflow_stack_base;
191 	unsigned long fp;
192 	unsigned long pc;
193 };
194 
195 /* Translate a kernel address @ptr into its equivalent linear mapping */
196 #define kvm_ksym_ref(ptr)						\
197 	({								\
198 		void *val = (ptr);					\
199 		if (!is_kernel_in_hyp_mode())				\
200 			val = lm_alias((ptr));				\
201 		val;							\
202 	 })
203 #define kvm_ksym_ref_nvhe(sym)	kvm_ksym_ref(kvm_nvhe_sym(sym))
204 
205 struct kvm;
206 struct kvm_vcpu;
207 struct kvm_s2_mmu;
208 
209 DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
210 DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
211 #define __kvm_hyp_init		CHOOSE_NVHE_SYM(__kvm_hyp_init)
212 #define __kvm_hyp_vector	CHOOSE_HYP_SYM(__kvm_hyp_vector)
213 
214 extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
215 DECLARE_KVM_NVHE_SYM(__per_cpu_start);
216 DECLARE_KVM_NVHE_SYM(__per_cpu_end);
217 
218 DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
219 #define __bp_harden_hyp_vecs	CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
220 
221 extern void __kvm_flush_vm_context(void);
222 extern void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu);
223 extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
224 				     int level);
225 extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
226 
227 extern void __kvm_timer_set_cntvoff(u64 cntvoff);
228 
229 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
230 
231 extern void __kvm_adjust_pc(struct kvm_vcpu *vcpu);
232 
233 extern u64 __vgic_v3_get_gic_config(void);
234 extern u64 __vgic_v3_read_vmcr(void);
235 extern void __vgic_v3_write_vmcr(u32 vmcr);
236 extern void __vgic_v3_init_lrs(void);
237 
238 extern u64 __kvm_get_mdcr_el2(void);
239 
240 #define __KVM_EXTABLE(from, to)						\
241 	"	.pushsection	__kvm_ex_table, \"a\"\n"		\
242 	"	.align		3\n"					\
243 	"	.long		(" #from " - .), (" #to " - .)\n"	\
244 	"	.popsection\n"
245 
246 
247 #define __kvm_at(at_op, addr)						\
248 ( { 									\
249 	int __kvm_at_err = 0;						\
250 	u64 spsr, elr;							\
251 	asm volatile(							\
252 	"	mrs	%1, spsr_el2\n"					\
253 	"	mrs	%2, elr_el2\n"					\
254 	"1:	at	"at_op", %3\n"					\
255 	"	isb\n"							\
256 	"	b	9f\n"						\
257 	"2:	msr	spsr_el2, %1\n"					\
258 	"	msr	elr_el2, %2\n"					\
259 	"	mov	%w0, %4\n"					\
260 	"9:\n"								\
261 	__KVM_EXTABLE(1b, 2b)						\
262 	: "+r" (__kvm_at_err), "=&r" (spsr), "=&r" (elr)		\
263 	: "r" (addr), "i" (-EFAULT));					\
264 	__kvm_at_err;							\
265 } )
266 
267 
268 #else /* __ASSEMBLY__ */
269 
270 .macro get_host_ctxt reg, tmp
271 	adr_this_cpu \reg, kvm_host_data, \tmp
272 	add	\reg, \reg, #HOST_DATA_CONTEXT
273 .endm
274 
275 .macro get_vcpu_ptr vcpu, ctxt
276 	get_host_ctxt \ctxt, \vcpu
277 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
278 .endm
279 
280 .macro get_loaded_vcpu vcpu, ctxt
281 	adr_this_cpu \ctxt, kvm_hyp_ctxt, \vcpu
282 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
283 .endm
284 
285 .macro set_loaded_vcpu vcpu, ctxt, tmp
286 	adr_this_cpu \ctxt, kvm_hyp_ctxt, \tmp
287 	str	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
288 .endm
289 
290 /*
291  * KVM extable for unexpected exceptions.
292  * Create a struct kvm_exception_table_entry output to a section that can be
293  * mapped by EL2. The table is not sorted.
294  *
295  * The caller must ensure:
296  * x18 has the hypervisor value to allow any Shadow-Call-Stack instrumented
297  * code to write to it, and that SPSR_EL2 and ELR_EL2 are restored by the fixup.
298  */
299 .macro	_kvm_extable, from, to
300 	.pushsection	__kvm_ex_table, "a"
301 	.align		3
302 	.long		(\from - .), (\to - .)
303 	.popsection
304 .endm
305 
306 #define CPU_XREG_OFFSET(x)	(CPU_USER_PT_REGS + 8*x)
307 #define CPU_LR_OFFSET		CPU_XREG_OFFSET(30)
308 #define CPU_SP_EL0_OFFSET	(CPU_LR_OFFSET + 8)
309 
310 /*
311  * We treat x18 as callee-saved as the host may use it as a platform
312  * register (e.g. for shadow call stack).
313  */
314 .macro save_callee_saved_regs ctxt
315 	str	x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
316 	stp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
317 	stp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
318 	stp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
319 	stp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
320 	stp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
321 	stp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
322 .endm
323 
324 .macro restore_callee_saved_regs ctxt
325 	// We require \ctxt is not x18-x28
326 	ldr	x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
327 	ldp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
328 	ldp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
329 	ldp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
330 	ldp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
331 	ldp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
332 	ldp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
333 .endm
334 
335 .macro save_sp_el0 ctxt, tmp
336 	mrs	\tmp,	sp_el0
337 	str	\tmp,	[\ctxt, #CPU_SP_EL0_OFFSET]
338 .endm
339 
340 .macro restore_sp_el0 ctxt, tmp
341 	ldr	\tmp,	  [\ctxt, #CPU_SP_EL0_OFFSET]
342 	msr	sp_el0, \tmp
343 .endm
344 
345 #endif
346 
347 #endif /* __ARM_KVM_ASM_H__ */
348