summaryrefslogtreecommitdiff
path: root/arch/arm64/kvm/hyp/switch.c
blob: 75e83dd40d43b269a0ef7e6c398cb958a800b1bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
/*
 * Copyright (C) 2015 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/types.h>
#include <linux/jump_label.h>

#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
#include <asm/fpsimd.h>

static bool __hyp_text __fpsimd_enabled_nvhe(void)
{
	return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
}

static bool __hyp_text __fpsimd_enabled_vhe(void)
{
	return !!(read_sysreg(cpacr_el1) & CPACR_EL1_FPEN);
}

static hyp_alternate_select(__fpsimd_is_enabled,
			    __fpsimd_enabled_nvhe, __fpsimd_enabled_vhe,
			    ARM64_HAS_VIRT_HOST_EXTN);

bool __hyp_text __fpsimd_enabled(void)
{
	return __fpsimd_is_enabled()();
}

static void __hyp_text __activate_traps_vhe(void)
{
	u64 val;

	val = read_sysreg(cpacr_el1);
	val |= CPACR_EL1_TTA;
	val &= ~CPACR_EL1_FPEN;
	write_sysreg(val, cpacr_el1);

	write_sysreg(__kvm_hyp_vector, vbar_el1);
}

static void __hyp_text __activate_traps_nvhe(void)
{
	u64 val;

	val = CPTR_EL2_DEFAULT;
	val |= CPTR_EL2_TTA | CPTR_EL2_TFP;
	write_sysreg(val, cptr_el2);
}

static hyp_alternate_select(__activate_traps_arch,
			    __activate_traps_nvhe, __activate_traps_vhe,
			    ARM64_HAS_VIRT_HOST_EXTN);

static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
{
	u64 val;

	/*
	 * We are about to set CPTR_EL2.TFP to trap all floating point
	 * register accesses to EL2, however, the ARM ARM clearly states that
	 * traps are only taken to EL2 if the operation would not otherwise
	 * trap to EL1.  Therefore, always make sure that for 32-bit guests,
	 * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
	 * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
	 * it will cause an exception.
	 */
	val = vcpu->arch.hcr_el2;
	if (!(val & HCR_RW) && system_supports_fpsimd()) {
		write_sysreg(1 << 30, fpexc32_el2);
		isb();
	}
	write_sysreg(val, hcr_el2);
	/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
	write_sysreg(1 << 15, hstr_el2);
	/*
	 * Make sure we trap PMU access from EL0 to EL2. Also sanitize
	 * PMSELR_EL0 to make sure it never contains the cycle
	 * counter, which could make a PMXEVCNTR_EL0 access UNDEF at
	 * EL1 instead of being trapped to EL2.
	 */
	write_sysreg(0, pmselr_el0);
	write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
	__activate_traps_arch()();
}

static void __hyp_text __deactivate_traps_vhe(void)
{
	extern char vectors[];	/* kernel exception vectors */

	write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
	write_sysreg(CPACR_EL1_FPEN, cpacr_el1);
	write_sysreg(vectors, vbar_el1);
}

static void __hyp_text __deactivate_traps_nvhe(void)
{
	write_sysreg(HCR_RW, hcr_el2);
	write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
}

static hyp_alternate_select(__deactivate_traps_arch,
			    __deactivate_traps_nvhe, __deactivate_traps_vhe,
			    ARM64_HAS_VIRT_HOST_EXTN);

static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
{
	/*
	 * If we pended a virtual abort, preserve it until it gets
	 * cleared. See D1.14.3 (Virtual Interrupts) for details, but
	 * the crucial bit is "On taking a vSError interrupt,
	 * HCR_EL2.VSE is cleared to 0."
	 */
	if (vcpu->arch.hcr_el2 & HCR_VSE)
		vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);

	__deactivate_traps_arch()();
	write_sysreg(0, hstr_el2);
	write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2);
	write_sysreg(0, pmuserenr_el0);
}

static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
{
	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
	write_sysreg(kvm->arch.vttbr, vttbr_el2);
}

static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
{
	write_sysreg(0, vttbr_el2);
}

static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
{
	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
		__vgic_v3_save_state(vcpu);
	else
		__vgic_v2_save_state(vcpu);

	write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2);
}

static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
{
	u64 val;

	val = read_sysreg(hcr_el2);
	val |= 	HCR_INT_OVERRIDE;
	val |= vcpu->arch.irq_lines;
	write_sysreg(val, hcr_el2);

	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
		__vgic_v3_restore_state(vcpu);
	else
		__vgic_v2_restore_state(vcpu);
}

static bool __hyp_text __true_value(void)
{
	return true;
}

static bool __hyp_text __false_value(void)
{
	return false;
}

static hyp_alternate_select(__check_arm_834220,
			    __false_value, __true_value,
			    ARM64_WORKAROUND_834220);

static bool __hyp_text __translate_far_to_hpfar(u64 far, u64 *hpfar)
{
	u64 par, tmp;

	/*
	 * Resolve the IPA the hard way using the guest VA.
	 *
	 * Stage-1 translation already validated the memory access
	 * rights. As such, we can use the EL1 translation regime, and
	 * don't have to distinguish between EL0 and EL1 access.
	 *
	 * We do need to save/restore PAR_EL1 though, as we haven't
	 * saved the guest context yet, and we may return early...
	 */
	par = read_sysreg(par_el1);
	asm volatile("at s1e1r, %0" : : "r" (far));
	isb();

	tmp = read_sysreg(par_el1);
	write_sysreg(par, par_el1);

	if (unlikely(tmp & 1))
		return false; /* Translation failed, back to guest */

	/* Convert PAR to HPFAR format */
	*hpfar = ((tmp >> 12) & ((1UL << 36) - 1)) << 4;
	return true;
}

static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
{
	u64 esr = read_sysreg_el2(esr);
	u8 ec = ESR_ELx_EC(esr);
	u64 hpfar, far;

	vcpu->arch.fault.esr_el2 = esr;

	if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW)
		return true;

	far = read_sysreg_el2(far);

	/*
	 * The HPFAR can be invalid if the stage 2 fault did not
	 * happen during a stage 1 page table walk (the ESR_EL2.S1PTW
	 * bit is clear) and one of the two following cases are true:
	 *   1. The fault was due to a permission fault
	 *   2. The processor carries errata 834220
	 *
	 * Therefore, for all non S1PTW faults where we either have a
	 * permission fault or the errata workaround is enabled, we
	 * resolve the IPA using the AT instruction.
	 */
	if (!(esr & ESR_ELx_S1PTW) &&
	    (__check_arm_834220()() || (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) {
		if (!__translate_far_to_hpfar(far, &hpfar))
			return false;
	} else {
		hpfar = read_sysreg(hpfar_el2);
	}

	vcpu->arch.fault.far_el2 = far;
	vcpu->arch.fault.hpfar_el2 = hpfar;
	return true;
}

static void __hyp_text __skip_instr(struct kvm_vcpu *vcpu)
{
	*vcpu_pc(vcpu) = read_sysreg_el2(elr);

	if (vcpu_mode_is_32bit(vcpu)) {
		vcpu->arch.ctxt.gp_regs.regs.pstate = read_sysreg_el2(spsr);
		kvm_skip_instr32(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
		write_sysreg_el2(vcpu->arch.ctxt.gp_regs.regs.pstate, spsr);
	} else {
		*vcpu_pc(vcpu) += 4;
	}

	write_sysreg_el2(*vcpu_pc(vcpu), elr);
}

int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
{
	struct kvm_cpu_context *host_ctxt;
	struct kvm_cpu_context *guest_ctxt;
	bool fp_enabled;
	u64 exit_code;

	vcpu = kern_hyp_va(vcpu);
	write_sysreg(vcpu, tpidr_el2);

	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
	guest_ctxt = &vcpu->arch.ctxt;

	__sysreg_save_host_state(host_ctxt);
	__debug_cond_save_host_state(vcpu);

	__activate_traps(vcpu);
	__activate_vm(vcpu);

	__vgic_restore_state(vcpu);
	__timer_restore_state(vcpu);

	/*
	 * We must restore the 32-bit state before the sysregs, thanks
	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
	 */
	__sysreg32_restore_state(vcpu);
	__sysreg_restore_guest_state(guest_ctxt);
	__debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);

	/* Jump in the fire! */
again:
	exit_code = __guest_enter(vcpu, host_ctxt);
	/* And we're baaack! */

	/*
	 * We're using the raw exception code in order to only process
	 * the trap if no SError is pending. We will come back to the
	 * same PC once the SError has been injected, and replay the
	 * trapping instruction.
	 */
	if (exit_code == ARM_EXCEPTION_TRAP && !__populate_fault_info(vcpu))
		goto again;

	if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&
	    exit_code == ARM_EXCEPTION_TRAP) {
		bool valid;

		valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW &&
			kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT &&
			kvm_vcpu_dabt_isvalid(vcpu) &&
			!kvm_vcpu_dabt_isextabt(vcpu) &&
			!kvm_vcpu_dabt_iss1tw(vcpu);

		if (valid) {
			int ret = __vgic_v2_perform_cpuif_access(vcpu);

			if (ret == 1) {
				__skip_instr(vcpu);
				goto again;
			}

			if (ret == -1) {
				/* Promote an illegal access to an SError */
				__skip_instr(vcpu);
				exit_code = ARM_EXCEPTION_EL1_SERROR;
			}

			/* 0 falls through to be handler out of EL2 */
		}
	}

	fp_enabled = __fpsimd_enabled();

	__sysreg_save_guest_state(guest_ctxt);
	__sysreg32_save_state(vcpu);
	__timer_save_state(vcpu);
	__vgic_save_state(vcpu);

	__deactivate_traps(vcpu);
	__deactivate_vm(vcpu);

	__sysreg_restore_host_state(host_ctxt);

	if (fp_enabled) {
		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
		__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
	}

	__debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
	__debug_cond_restore_host_state(vcpu);

	return exit_code;
}

static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";

static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par)
{
	unsigned long str_va;

	/*
	 * Force the panic string to be loaded from the literal pool,
	 * making sure it is a kernel address and not a PC-relative
	 * reference.
	 */
	asm volatile("ldr %0, =__hyp_panic_string" : "=r" (str_va));

	__hyp_do_panic(str_va,
		       spsr,  elr,
		       read_sysreg(esr_el2),   read_sysreg_el2(far),
		       read_sysreg(hpfar_el2), par,
		       (void *)read_sysreg(tpidr_el2));
}

static void __hyp_text __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par)
{
	panic(__hyp_panic_string,
	      spsr,  elr,
	      read_sysreg_el2(esr),   read_sysreg_el2(far),
	      read_sysreg(hpfar_el2), par,
	      (void *)read_sysreg(tpidr_el2));
}

static hyp_alternate_select(__hyp_call_panic,
			    __hyp_call_panic_nvhe, __hyp_call_panic_vhe,
			    ARM64_HAS_VIRT_HOST_EXTN);

void __hyp_text __noreturn __hyp_panic(void)
{
	u64 spsr = read_sysreg_el2(spsr);
	u64 elr = read_sysreg_el2(elr);
	u64 par = read_sysreg(par_el1);

	if (read_sysreg(vttbr_el2)) {
		struct kvm_vcpu *vcpu;
		struct kvm_cpu_context *host_ctxt;

		vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2);
		host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
		__deactivate_traps(vcpu);
		__deactivate_vm(vcpu);
		__sysreg_restore_host_state(host_ctxt);
	}

	/* Call panic for real */
	__hyp_call_panic()(spsr, elr, par);

	unreachable();
}