xref: /openbmc/linux/arch/arm64/include/asm/kvm_asm.h (revision 6354d150)
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_ipa_nsh,
72 	__KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid,
73 	__KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_range,
74 	__KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context,
75 	__KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff,
76 	__KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr,
77 	__KVM_HOST_SMCCC_FUNC___vgic_v3_write_vmcr,
78 	__KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs,
79 	__KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs,
80 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_init_traps,
81 	__KVM_HOST_SMCCC_FUNC___pkvm_init_vm,
82 	__KVM_HOST_SMCCC_FUNC___pkvm_init_vcpu,
83 	__KVM_HOST_SMCCC_FUNC___pkvm_teardown_vm,
84 };
85 
86 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]
87 #define DECLARE_KVM_NVHE_SYM(sym)	extern char kvm_nvhe_sym(sym)[]
88 
89 /*
90  * Define a pair of symbols sharing the same name but one defined in
91  * VHE and the other in nVHE hyp implementations.
92  */
93 #define DECLARE_KVM_HYP_SYM(sym)		\
94 	DECLARE_KVM_VHE_SYM(sym);		\
95 	DECLARE_KVM_NVHE_SYM(sym)
96 
97 #define DECLARE_KVM_VHE_PER_CPU(type, sym)	\
98 	DECLARE_PER_CPU(type, sym)
99 #define DECLARE_KVM_NVHE_PER_CPU(type, sym)	\
100 	DECLARE_PER_CPU(type, kvm_nvhe_sym(sym))
101 
102 #define DECLARE_KVM_HYP_PER_CPU(type, sym)	\
103 	DECLARE_KVM_VHE_PER_CPU(type, sym);	\
104 	DECLARE_KVM_NVHE_PER_CPU(type, sym)
105 
106 /*
107  * Compute pointer to a symbol defined in nVHE percpu region.
108  * Returns NULL if percpu memory has not been allocated yet.
109  */
110 #define this_cpu_ptr_nvhe_sym(sym)	per_cpu_ptr_nvhe_sym(sym, smp_processor_id())
111 #define per_cpu_ptr_nvhe_sym(sym, cpu)						\
112 	({									\
113 		unsigned long base, off;					\
114 		base = kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[cpu];		\
115 		off = (unsigned long)&CHOOSE_NVHE_SYM(sym) -			\
116 		      (unsigned long)&CHOOSE_NVHE_SYM(__per_cpu_start);		\
117 		base ? (typeof(CHOOSE_NVHE_SYM(sym))*)(base + off) : NULL;	\
118 	})
119 
120 #if defined(__KVM_NVHE_HYPERVISOR__)
121 
122 #define CHOOSE_NVHE_SYM(sym)	sym
123 #define CHOOSE_HYP_SYM(sym)	CHOOSE_NVHE_SYM(sym)
124 
125 /* The nVHE hypervisor shouldn't even try to access VHE symbols */
126 extern void *__nvhe_undefined_symbol;
127 #define CHOOSE_VHE_SYM(sym)		__nvhe_undefined_symbol
128 #define this_cpu_ptr_hyp_sym(sym)	(&__nvhe_undefined_symbol)
129 #define per_cpu_ptr_hyp_sym(sym, cpu)	(&__nvhe_undefined_symbol)
130 
131 #elif defined(__KVM_VHE_HYPERVISOR__)
132 
133 #define CHOOSE_VHE_SYM(sym)	sym
134 #define CHOOSE_HYP_SYM(sym)	CHOOSE_VHE_SYM(sym)
135 
136 /* The VHE hypervisor shouldn't even try to access nVHE symbols */
137 extern void *__vhe_undefined_symbol;
138 #define CHOOSE_NVHE_SYM(sym)		__vhe_undefined_symbol
139 #define this_cpu_ptr_hyp_sym(sym)	(&__vhe_undefined_symbol)
140 #define per_cpu_ptr_hyp_sym(sym, cpu)	(&__vhe_undefined_symbol)
141 
142 #else
143 
144 /*
145  * BIG FAT WARNINGS:
146  *
147  * - Don't be tempted to change the following is_kernel_in_hyp_mode()
148  *   to has_vhe(). has_vhe() is implemented as a *final* capability,
149  *   while this is used early at boot time, when the capabilities are
150  *   not final yet....
151  *
152  * - Don't let the nVHE hypervisor have access to this, as it will
153  *   pick the *wrong* symbol (yes, it runs at EL2...).
154  */
155 #define CHOOSE_HYP_SYM(sym)		(is_kernel_in_hyp_mode()	\
156 					   ? CHOOSE_VHE_SYM(sym)	\
157 					   : CHOOSE_NVHE_SYM(sym))
158 
159 #define this_cpu_ptr_hyp_sym(sym)	(is_kernel_in_hyp_mode()	\
160 					   ? this_cpu_ptr(&sym)		\
161 					   : this_cpu_ptr_nvhe_sym(sym))
162 
163 #define per_cpu_ptr_hyp_sym(sym, cpu)	(is_kernel_in_hyp_mode()	\
164 					   ? per_cpu_ptr(&sym, cpu)	\
165 					   : per_cpu_ptr_nvhe_sym(sym, cpu))
166 
167 #define CHOOSE_VHE_SYM(sym)	sym
168 #define CHOOSE_NVHE_SYM(sym)	kvm_nvhe_sym(sym)
169 
170 #endif
171 
172 struct kvm_nvhe_init_params {
173 	unsigned long mair_el2;
174 	unsigned long tcr_el2;
175 	unsigned long tpidr_el2;
176 	unsigned long stack_hyp_va;
177 	unsigned long stack_pa;
178 	phys_addr_t pgd_pa;
179 	unsigned long hcr_el2;
180 	unsigned long vttbr;
181 	unsigned long vtcr;
182 };
183 
184 /*
185  * Used by the host in EL1 to dump the nVHE hypervisor backtrace on
186  * hyp_panic() in non-protected mode.
187  *
188  * @stack_base:                 hyp VA of the hyp_stack base.
189  * @overflow_stack_base:        hyp VA of the hyp_overflow_stack base.
190  * @fp:                         hyp FP where the backtrace begins.
191  * @pc:                         hyp PC where the backtrace begins.
192  */
193 struct kvm_nvhe_stacktrace_info {
194 	unsigned long stack_base;
195 	unsigned long overflow_stack_base;
196 	unsigned long fp;
197 	unsigned long pc;
198 };
199 
200 /* Translate a kernel address @ptr into its equivalent linear mapping */
201 #define kvm_ksym_ref(ptr)						\
202 	({								\
203 		void *val = (ptr);					\
204 		if (!is_kernel_in_hyp_mode())				\
205 			val = lm_alias((ptr));				\
206 		val;							\
207 	 })
208 #define kvm_ksym_ref_nvhe(sym)	kvm_ksym_ref(kvm_nvhe_sym(sym))
209 
210 struct kvm;
211 struct kvm_vcpu;
212 struct kvm_s2_mmu;
213 
214 DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
215 DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
216 #define __kvm_hyp_init		CHOOSE_NVHE_SYM(__kvm_hyp_init)
217 #define __kvm_hyp_vector	CHOOSE_HYP_SYM(__kvm_hyp_vector)
218 
219 extern unsigned long kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[];
220 DECLARE_KVM_NVHE_SYM(__per_cpu_start);
221 DECLARE_KVM_NVHE_SYM(__per_cpu_end);
222 
223 DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
224 #define __bp_harden_hyp_vecs	CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
225 
226 extern void __kvm_flush_vm_context(void);
227 extern void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu);
228 extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
229 				     int level);
230 extern void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu,
231 					 phys_addr_t ipa,
232 					 int level);
233 extern void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
234 					phys_addr_t start, unsigned long pages);
235 extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
236 
237 extern void __kvm_timer_set_cntvoff(u64 cntvoff);
238 
239 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
240 
241 extern void __kvm_adjust_pc(struct kvm_vcpu *vcpu);
242 
243 extern u64 __vgic_v3_get_gic_config(void);
244 extern u64 __vgic_v3_read_vmcr(void);
245 extern void __vgic_v3_write_vmcr(u32 vmcr);
246 extern void __vgic_v3_init_lrs(void);
247 
248 extern u64 __kvm_get_mdcr_el2(void);
249 
250 #define __KVM_EXTABLE(from, to)						\
251 	"	.pushsection	__kvm_ex_table, \"a\"\n"		\
252 	"	.align		3\n"					\
253 	"	.long		(" #from " - .), (" #to " - .)\n"	\
254 	"	.popsection\n"
255 
256 
257 #define __kvm_at(at_op, addr)						\
258 ( { 									\
259 	int __kvm_at_err = 0;						\
260 	u64 spsr, elr;							\
261 	asm volatile(							\
262 	"	mrs	%1, spsr_el2\n"					\
263 	"	mrs	%2, elr_el2\n"					\
264 	"1:	at	"at_op", %3\n"					\
265 	"	isb\n"							\
266 	"	b	9f\n"						\
267 	"2:	msr	spsr_el2, %1\n"					\
268 	"	msr	elr_el2, %2\n"					\
269 	"	mov	%w0, %4\n"					\
270 	"9:\n"								\
271 	__KVM_EXTABLE(1b, 2b)						\
272 	: "+r" (__kvm_at_err), "=&r" (spsr), "=&r" (elr)		\
273 	: "r" (addr), "i" (-EFAULT));					\
274 	__kvm_at_err;							\
275 } )
276 
277 void __noreturn hyp_panic(void);
278 asmlinkage void kvm_unexpected_el2_exception(void);
279 asmlinkage void __noreturn hyp_panic(void);
280 asmlinkage void __noreturn hyp_panic_bad_stack(void);
281 asmlinkage void kvm_unexpected_el2_exception(void);
282 struct kvm_cpu_context;
283 void handle_trap(struct kvm_cpu_context *host_ctxt);
284 asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on);
285 void __noreturn __pkvm_init_finalise(void);
286 void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
287 void kvm_patch_vector_branch(struct alt_instr *alt,
288 	__le32 *origptr, __le32 *updptr, int nr_inst);
289 void kvm_get_kimage_voffset(struct alt_instr *alt,
290 	__le32 *origptr, __le32 *updptr, int nr_inst);
291 void kvm_compute_final_ctr_el0(struct alt_instr *alt,
292 	__le32 *origptr, __le32 *updptr, int nr_inst);
293 void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr, u64 elr_virt,
294 	u64 elr_phys, u64 par, uintptr_t vcpu, u64 far, u64 hpfar);
295 
296 #else /* __ASSEMBLY__ */
297 
298 .macro get_host_ctxt reg, tmp
299 	adr_this_cpu \reg, kvm_host_data, \tmp
300 	add	\reg, \reg, #HOST_DATA_CONTEXT
301 .endm
302 
303 .macro get_vcpu_ptr vcpu, ctxt
304 	get_host_ctxt \ctxt, \vcpu
305 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
306 .endm
307 
308 .macro get_loaded_vcpu vcpu, ctxt
309 	adr_this_cpu \ctxt, kvm_hyp_ctxt, \vcpu
310 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
311 .endm
312 
313 .macro set_loaded_vcpu vcpu, ctxt, tmp
314 	adr_this_cpu \ctxt, kvm_hyp_ctxt, \tmp
315 	str	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
316 .endm
317 
318 /*
319  * KVM extable for unexpected exceptions.
320  * Create a struct kvm_exception_table_entry output to a section that can be
321  * mapped by EL2. The table is not sorted.
322  *
323  * The caller must ensure:
324  * x18 has the hypervisor value to allow any Shadow-Call-Stack instrumented
325  * code to write to it, and that SPSR_EL2 and ELR_EL2 are restored by the fixup.
326  */
327 .macro	_kvm_extable, from, to
328 	.pushsection	__kvm_ex_table, "a"
329 	.align		3
330 	.long		(\from - .), (\to - .)
331 	.popsection
332 .endm
333 
334 #define CPU_XREG_OFFSET(x)	(CPU_USER_PT_REGS + 8*x)
335 #define CPU_LR_OFFSET		CPU_XREG_OFFSET(30)
336 #define CPU_SP_EL0_OFFSET	(CPU_LR_OFFSET + 8)
337 
338 /*
339  * We treat x18 as callee-saved as the host may use it as a platform
340  * register (e.g. for shadow call stack).
341  */
342 .macro save_callee_saved_regs ctxt
343 	str	x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
344 	stp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
345 	stp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
346 	stp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
347 	stp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
348 	stp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
349 	stp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
350 .endm
351 
352 .macro restore_callee_saved_regs ctxt
353 	// We require \ctxt is not x18-x28
354 	ldr	x18,      [\ctxt, #CPU_XREG_OFFSET(18)]
355 	ldp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
356 	ldp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
357 	ldp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
358 	ldp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
359 	ldp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
360 	ldp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
361 .endm
362 
363 .macro save_sp_el0 ctxt, tmp
364 	mrs	\tmp,	sp_el0
365 	str	\tmp,	[\ctxt, #CPU_SP_EL0_OFFSET]
366 .endm
367 
368 .macro restore_sp_el0 ctxt, tmp
369 	ldr	\tmp,	  [\ctxt, #CPU_SP_EL0_OFFSET]
370 	msr	sp_el0, \tmp
371 .endm
372 
373 #endif
374 
375 #endif /* __ARM_KVM_ASM_H__ */
376