summaryrefslogtreecommitdiff
path: root/arch/arm64/kvm/reset.c
blob: ecc40c8cd6f643301c4c3a76f9eb6933ca8350e7 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012,2013 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * Derived from arch/arm/kvm/reset.c
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/hw_breakpoint.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>

#include <kvm/arm_arch_timer.h>

#include <asm/cpufeature.h>
#include <asm/cputype.h>
#include <asm/fpsimd.h>
#include <asm/ptrace.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_mmu.h>
#include <asm/virt.h>

/* Maximum phys_shift supported for any VM on this host */
static u32 kvm_ipa_limit;

/*
 * ARMv8 Reset Values
 */
#define VCPU_RESET_PSTATE_EL1	(PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
				 PSR_F_BIT | PSR_D_BIT)

#define VCPU_RESET_PSTATE_SVC	(PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
				 PSR_AA32_I_BIT | PSR_AA32_F_BIT)

unsigned int kvm_sve_max_vl;

int kvm_arm_init_sve(void)
{
	if (system_supports_sve()) {
		kvm_sve_max_vl = sve_max_virtualisable_vl();

		/*
		 * The get_sve_reg()/set_sve_reg() ioctl interface will need
		 * to be extended with multiple register slice support in
		 * order to support vector lengths greater than
		 * VL_ARCH_MAX:
		 */
		if (WARN_ON(kvm_sve_max_vl > VL_ARCH_MAX))
			kvm_sve_max_vl = VL_ARCH_MAX;

		/*
		 * Don't even try to make use of vector lengths that
		 * aren't available on all CPUs, for now:
		 */
		if (kvm_sve_max_vl < sve_max_vl())
			pr_warn("KVM: SVE vector length for guests limited to %u bytes\n",
				kvm_sve_max_vl);
	}

	return 0;
}

static int kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
{
	if (!system_supports_sve())
		return -EINVAL;

	vcpu->arch.sve_max_vl = kvm_sve_max_vl;

	/*
	 * Userspace can still customize the vector lengths by writing
	 * KVM_REG_ARM64_SVE_VLS.  Allocation is deferred until
	 * kvm_arm_vcpu_finalize(), which freezes the configuration.
	 */
	vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_SVE;

	return 0;
}

/*
 * Finalize vcpu's maximum SVE vector length, allocating
 * vcpu->arch.sve_state as necessary.
 */
static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
{
	void *buf;
	unsigned int vl;
	size_t reg_sz;
	int ret;

	vl = vcpu->arch.sve_max_vl;

	/*
	 * Responsibility for these properties is shared between
	 * kvm_arm_init_sve(), kvm_vcpu_enable_sve() and
	 * set_sve_vls().  Double-check here just to be sure:
	 */
	if (WARN_ON(!sve_vl_valid(vl) || vl > sve_max_virtualisable_vl() ||
		    vl > VL_ARCH_MAX))
		return -EIO;

	reg_sz = vcpu_sve_state_size(vcpu);
	buf = kzalloc(reg_sz, GFP_KERNEL_ACCOUNT);
	if (!buf)
		return -ENOMEM;

	ret = kvm_share_hyp(buf, buf + reg_sz);
	if (ret) {
		kfree(buf);
		return ret;
	}
	
	vcpu->arch.sve_state = buf;
	vcpu->arch.flags |= KVM_ARM64_VCPU_SVE_FINALIZED;
	return 0;
}

int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
{
	switch (feature) {
	case KVM_ARM_VCPU_SVE:
		if (!vcpu_has_sve(vcpu))
			return -EINVAL;

		if (kvm_arm_vcpu_sve_finalized(vcpu))
			return -EPERM;

		return kvm_vcpu_finalize_sve(vcpu);
	}

	return -EINVAL;
}

bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
{
	if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
		return false;

	return true;
}

void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
	void *sve_state = vcpu->arch.sve_state;

	kvm_vcpu_unshare_task_fp(vcpu);
	kvm_unshare_hyp(vcpu, vcpu + 1);
	if (sve_state)
		kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));
	kfree(sve_state);
}

static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
{
	if (vcpu_has_sve(vcpu))
		memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu));
}

static int kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
{
	/*
	 * For now make sure that both address/generic pointer authentication
	 * features are requested by the userspace together and the system
	 * supports these capabilities.
	 */
	if (!test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
	    !test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features) ||
	    !system_has_full_ptr_auth())
		return -EINVAL;

	vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_PTRAUTH;
	return 0;
}

static bool vcpu_allowed_register_width(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu *tmp;
	bool is32bit;
	unsigned long i;

	is32bit = vcpu_has_feature(vcpu, KVM_ARM_VCPU_EL1_32BIT);
	if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1) && is32bit)
		return false;

	/* MTE is incompatible with AArch32 */
	if (kvm_has_mte(vcpu->kvm) && is32bit)
		return false;

	/* Check that the vcpus are either all 32bit or all 64bit */
	kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
		if (vcpu_has_feature(tmp, KVM_ARM_VCPU_EL1_32BIT) != is32bit)
			return false;
	}

	return true;
}

/**
 * kvm_reset_vcpu - sets core registers and sys_regs to reset value
 * @vcpu: The VCPU pointer
 *
 * This function sets the registers on the virtual CPU struct to their
 * architecturally defined reset values, except for registers whose reset is
 * deferred until kvm_arm_vcpu_finalize().
 *
 * Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT
 * ioctl or as part of handling a request issued by another VCPU in the PSCI
 * handling code.  In the first case, the VCPU will not be loaded, and in the
 * second case the VCPU will be loaded.  Because this function operates purely
 * on the memory-backed values of system registers, we want to do a full put if
 * we were loaded (handling a request) and load the values back at the end of
 * the function.  Otherwise we leave the state alone.  In both cases, we
 * disable preemption around the vcpu reset as we would otherwise race with
 * preempt notifiers which also call put/load.
 */
int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
{
	struct vcpu_reset_state reset_state;
	int ret;
	bool loaded;
	u32 pstate;

	mutex_lock(&vcpu->kvm->lock);
	reset_state = vcpu->arch.reset_state;
	WRITE_ONCE(vcpu->arch.reset_state.reset, false);
	mutex_unlock(&vcpu->kvm->lock);

	/* Reset PMU outside of the non-preemptible section */
	kvm_pmu_vcpu_reset(vcpu);

	preempt_disable();
	loaded = (vcpu->cpu != -1);
	if (loaded)
		kvm_arch_vcpu_put(vcpu);

	if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
		if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features)) {
			ret = kvm_vcpu_enable_sve(vcpu);
			if (ret)
				goto out;
		}
	} else {
		kvm_vcpu_reset_sve(vcpu);
	}

	if (test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
	    test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features)) {
		if (kvm_vcpu_enable_ptrauth(vcpu)) {
			ret = -EINVAL;
			goto out;
		}
	}

	if (!vcpu_allowed_register_width(vcpu)) {
		ret = -EINVAL;
		goto out;
	}

	switch (vcpu->arch.target) {
	default:
		if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
			pstate = VCPU_RESET_PSTATE_SVC;
		} else {
			pstate = VCPU_RESET_PSTATE_EL1;
		}

		if (kvm_vcpu_has_pmu(vcpu) && !kvm_arm_support_pmu_v3()) {
			ret = -EINVAL;
			goto out;
		}
		break;
	}

	/* Reset core registers */
	memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
	memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
	vcpu->arch.ctxt.spsr_abt = 0;
	vcpu->arch.ctxt.spsr_und = 0;
	vcpu->arch.ctxt.spsr_irq = 0;
	vcpu->arch.ctxt.spsr_fiq = 0;
	vcpu_gp_regs(vcpu)->pstate = pstate;

	/* Reset system registers */
	kvm_reset_sys_regs(vcpu);

	/*
	 * Additional reset state handling that PSCI may have imposed on us.
	 * Must be done after all the sys_reg reset.
	 */
	if (reset_state.reset) {
		unsigned long target_pc = reset_state.pc;

		/* Gracefully handle Thumb2 entry point */
		if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
			target_pc &= ~1UL;
			vcpu_set_thumb(vcpu);
		}

		/* Propagate caller endianness */
		if (reset_state.be)
			kvm_vcpu_set_be(vcpu);

		*vcpu_pc(vcpu) = target_pc;
		vcpu_set_reg(vcpu, 0, reset_state.r0);
	}

	/* Reset timer */
	ret = kvm_timer_vcpu_reset(vcpu);
out:
	if (loaded)
		kvm_arch_vcpu_load(vcpu, smp_processor_id());
	preempt_enable();
	return ret;
}

u32 get_kvm_ipa_limit(void)
{
	return kvm_ipa_limit;
}

int kvm_set_ipa_limit(void)
{
	unsigned int parange;
	u64 mmfr0;

	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
	parange = cpuid_feature_extract_unsigned_field(mmfr0,
				ID_AA64MMFR0_PARANGE_SHIFT);
	/*
	 * IPA size beyond 48 bits could not be supported
	 * on either 4K or 16K page size. Hence let's cap
	 * it to 48 bits, in case it's reported as larger
	 * on the system.
	 */
	if (PAGE_SIZE != SZ_64K)
		parange = min(parange, (unsigned int)ID_AA64MMFR0_PARANGE_48);

	/*
	 * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
	 * Stage-2. If not, things will stop very quickly.
	 */
	switch (cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_TGRAN_2_SHIFT)) {
	case ID_AA64MMFR0_TGRAN_2_SUPPORTED_NONE:
		kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
		return -EINVAL;
	case ID_AA64MMFR0_TGRAN_2_SUPPORTED_DEFAULT:
		kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
		break;
	case ID_AA64MMFR0_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_TGRAN_2_SUPPORTED_MAX:
		kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
		break;
	default:
		kvm_err("Unsupported value for TGRAN_2, giving up\n");
		return -EINVAL;
	}

	kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange);
	kvm_info("IPA Size Limit: %d bits%s\n", kvm_ipa_limit,
		 ((kvm_ipa_limit < KVM_PHYS_SHIFT) ?
		  " (Reduced IPA size, limited VM/VMM compatibility)" : ""));

	return 0;
}

int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
{
	u64 mmfr0, mmfr1;
	u32 phys_shift;

	if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
		return -EINVAL;

	phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
	if (phys_shift) {
		if (phys_shift > kvm_ipa_limit ||
		    phys_shift < ARM64_MIN_PARANGE_BITS)
			return -EINVAL;
	} else {
		phys_shift = KVM_PHYS_SHIFT;
		if (phys_shift > kvm_ipa_limit) {
			pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
				     current->comm);
			return -EINVAL;
		}
	}

	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
	mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
	kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);

	return 0;
}