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 * Derived from arch/arm/kvm/reset.c
7 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
8 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
9 */
10
11 #include <linux/errno.h>
12 #include <linux/kernel.h>
13 #include <linux/kvm_host.h>
14 #include <linux/kvm.h>
15 #include <linux/hw_breakpoint.h>
16 #include <linux/slab.h>
17 #include <linux/string.h>
18 #include <linux/types.h>
19
20 #include <kvm/arm_arch_timer.h>
21
22 #include <asm/cpufeature.h>
23 #include <asm/cputype.h>
24 #include <asm/fpsimd.h>
25 #include <asm/ptrace.h>
26 #include <asm/kvm_arm.h>
27 #include <asm/kvm_asm.h>
28 #include <asm/kvm_emulate.h>
29 #include <asm/kvm_mmu.h>
30 #include <asm/virt.h>
31
32 /* Maximum phys_shift supported for any VM on this host */
33 static u32 kvm_ipa_limit;
34
35 /*
36 * ARMv8 Reset Values
37 */
38 #define VCPU_RESET_PSTATE_EL1 (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
39 PSR_F_BIT | PSR_D_BIT)
40
41 #define VCPU_RESET_PSTATE_SVC (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
42 PSR_AA32_I_BIT | PSR_AA32_F_BIT)
43
44 unsigned int kvm_sve_max_vl;
45
kvm_arm_init_sve(void)46 int kvm_arm_init_sve(void)
47 {
48 if (system_supports_sve()) {
49 kvm_sve_max_vl = sve_max_virtualisable_vl();
50
51 /*
52 * The get_sve_reg()/set_sve_reg() ioctl interface will need
53 * to be extended with multiple register slice support in
54 * order to support vector lengths greater than
55 * VL_ARCH_MAX:
56 */
57 if (WARN_ON(kvm_sve_max_vl > VL_ARCH_MAX))
58 kvm_sve_max_vl = VL_ARCH_MAX;
59
60 /*
61 * Don't even try to make use of vector lengths that
62 * aren't available on all CPUs, for now:
63 */
64 if (kvm_sve_max_vl < sve_max_vl())
65 pr_warn("KVM: SVE vector length for guests limited to %u bytes\n",
66 kvm_sve_max_vl);
67 }
68
69 return 0;
70 }
71
kvm_vcpu_enable_sve(struct kvm_vcpu * vcpu)72 static int kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
73 {
74 if (!system_supports_sve())
75 return -EINVAL;
76
77 vcpu->arch.sve_max_vl = kvm_sve_max_vl;
78
79 /*
80 * Userspace can still customize the vector lengths by writing
81 * KVM_REG_ARM64_SVE_VLS. Allocation is deferred until
82 * kvm_arm_vcpu_finalize(), which freezes the configuration.
83 */
84 vcpu_set_flag(vcpu, GUEST_HAS_SVE);
85
86 return 0;
87 }
88
89 /*
90 * Finalize vcpu's maximum SVE vector length, allocating
91 * vcpu->arch.sve_state as necessary.
92 */
kvm_vcpu_finalize_sve(struct kvm_vcpu * vcpu)93 static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
94 {
95 void *buf;
96 unsigned int vl;
97 size_t reg_sz;
98 int ret;
99
100 vl = vcpu->arch.sve_max_vl;
101
102 /*
103 * Responsibility for these properties is shared between
104 * kvm_arm_init_sve(), kvm_vcpu_enable_sve() and
105 * set_sve_vls(). Double-check here just to be sure:
106 */
107 if (WARN_ON(!sve_vl_valid(vl) || vl > sve_max_virtualisable_vl() ||
108 vl > VL_ARCH_MAX))
109 return -EIO;
110
111 reg_sz = vcpu_sve_state_size(vcpu);
112 buf = kzalloc(reg_sz, GFP_KERNEL_ACCOUNT);
113 if (!buf)
114 return -ENOMEM;
115
116 ret = kvm_share_hyp(buf, buf + reg_sz);
117 if (ret) {
118 kfree(buf);
119 return ret;
120 }
121
122 vcpu->arch.sve_state = buf;
123 vcpu_set_flag(vcpu, VCPU_SVE_FINALIZED);
124 return 0;
125 }
126
kvm_arm_vcpu_finalize(struct kvm_vcpu * vcpu,int feature)127 int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
128 {
129 switch (feature) {
130 case KVM_ARM_VCPU_SVE:
131 if (!vcpu_has_sve(vcpu))
132 return -EINVAL;
133
134 if (kvm_arm_vcpu_sve_finalized(vcpu))
135 return -EPERM;
136
137 return kvm_vcpu_finalize_sve(vcpu);
138 }
139
140 return -EINVAL;
141 }
142
kvm_arm_vcpu_is_finalized(struct kvm_vcpu * vcpu)143 bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
144 {
145 if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
146 return false;
147
148 return true;
149 }
150
kvm_arm_vcpu_destroy(struct kvm_vcpu * vcpu)151 void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
152 {
153 void *sve_state = vcpu->arch.sve_state;
154
155 kvm_vcpu_unshare_task_fp(vcpu);
156 kvm_unshare_hyp(vcpu, vcpu + 1);
157 if (sve_state)
158 kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));
159 kfree(sve_state);
160 }
161
kvm_vcpu_reset_sve(struct kvm_vcpu * vcpu)162 static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
163 {
164 if (vcpu_has_sve(vcpu))
165 memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu));
166 }
167
kvm_vcpu_enable_ptrauth(struct kvm_vcpu * vcpu)168 static int kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
169 {
170 /*
171 * For now make sure that both address/generic pointer authentication
172 * features are requested by the userspace together and the system
173 * supports these capabilities.
174 */
175 if (!test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
176 !test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features) ||
177 !system_has_full_ptr_auth())
178 return -EINVAL;
179
180 vcpu_set_flag(vcpu, GUEST_HAS_PTRAUTH);
181 return 0;
182 }
183
184 /**
185 * kvm_set_vm_width() - set the register width for the guest
186 * @vcpu: Pointer to the vcpu being configured
187 *
188 * Set both KVM_ARCH_FLAG_EL1_32BIT and KVM_ARCH_FLAG_REG_WIDTH_CONFIGURED
189 * in the VM flags based on the vcpu's requested register width, the HW
190 * capabilities and other options (such as MTE).
191 * When REG_WIDTH_CONFIGURED is already set, the vcpu settings must be
192 * consistent with the value of the FLAG_EL1_32BIT bit in the flags.
193 *
194 * Return: 0 on success, negative error code on failure.
195 */
kvm_set_vm_width(struct kvm_vcpu * vcpu)196 static int kvm_set_vm_width(struct kvm_vcpu *vcpu)
197 {
198 struct kvm *kvm = vcpu->kvm;
199 bool is32bit;
200
201 is32bit = vcpu_has_feature(vcpu, KVM_ARM_VCPU_EL1_32BIT);
202
203 lockdep_assert_held(&kvm->lock);
204
205 if (test_bit(KVM_ARCH_FLAG_REG_WIDTH_CONFIGURED, &kvm->arch.flags)) {
206 /*
207 * The guest's register width is already configured.
208 * Make sure that the vcpu is consistent with it.
209 */
210 if (is32bit == test_bit(KVM_ARCH_FLAG_EL1_32BIT, &kvm->arch.flags))
211 return 0;
212
213 return -EINVAL;
214 }
215
216 if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1) && is32bit)
217 return -EINVAL;
218
219 /* MTE is incompatible with AArch32 */
220 if (kvm_has_mte(kvm) && is32bit)
221 return -EINVAL;
222
223 if (is32bit)
224 set_bit(KVM_ARCH_FLAG_EL1_32BIT, &kvm->arch.flags);
225
226 set_bit(KVM_ARCH_FLAG_REG_WIDTH_CONFIGURED, &kvm->arch.flags);
227
228 return 0;
229 }
230
231 /**
232 * kvm_reset_vcpu - sets core registers and sys_regs to reset value
233 * @vcpu: The VCPU pointer
234 *
235 * This function sets the registers on the virtual CPU struct to their
236 * architecturally defined reset values, except for registers whose reset is
237 * deferred until kvm_arm_vcpu_finalize().
238 *
239 * Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT
240 * ioctl or as part of handling a request issued by another VCPU in the PSCI
241 * handling code. In the first case, the VCPU will not be loaded, and in the
242 * second case the VCPU will be loaded. Because this function operates purely
243 * on the memory-backed values of system registers, we want to do a full put if
244 * we were loaded (handling a request) and load the values back at the end of
245 * the function. Otherwise we leave the state alone. In both cases, we
246 * disable preemption around the vcpu reset as we would otherwise race with
247 * preempt notifiers which also call put/load.
248 */
kvm_reset_vcpu(struct kvm_vcpu * vcpu)249 int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
250 {
251 struct vcpu_reset_state reset_state;
252 int ret;
253 bool loaded;
254 u32 pstate;
255
256 mutex_lock(&vcpu->kvm->lock);
257 ret = kvm_set_vm_width(vcpu);
258 if (!ret) {
259 reset_state = vcpu->arch.reset_state;
260 WRITE_ONCE(vcpu->arch.reset_state.reset, false);
261 }
262 mutex_unlock(&vcpu->kvm->lock);
263
264 if (ret)
265 return ret;
266
267 /* Reset PMU outside of the non-preemptible section */
268 kvm_pmu_vcpu_reset(vcpu);
269
270 preempt_disable();
271 loaded = (vcpu->cpu != -1);
272 if (loaded)
273 kvm_arch_vcpu_put(vcpu);
274
275 if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
276 if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features)) {
277 ret = kvm_vcpu_enable_sve(vcpu);
278 if (ret)
279 goto out;
280 }
281 } else {
282 kvm_vcpu_reset_sve(vcpu);
283 }
284
285 if (test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
286 test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features)) {
287 if (kvm_vcpu_enable_ptrauth(vcpu)) {
288 ret = -EINVAL;
289 goto out;
290 }
291 }
292
293 switch (vcpu->arch.target) {
294 default:
295 if (vcpu_el1_is_32bit(vcpu)) {
296 pstate = VCPU_RESET_PSTATE_SVC;
297 } else {
298 pstate = VCPU_RESET_PSTATE_EL1;
299 }
300
301 if (kvm_vcpu_has_pmu(vcpu) && !kvm_arm_support_pmu_v3()) {
302 ret = -EINVAL;
303 goto out;
304 }
305 break;
306 }
307
308 /* Reset core registers */
309 memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
310 memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
311 vcpu->arch.ctxt.spsr_abt = 0;
312 vcpu->arch.ctxt.spsr_und = 0;
313 vcpu->arch.ctxt.spsr_irq = 0;
314 vcpu->arch.ctxt.spsr_fiq = 0;
315 vcpu_gp_regs(vcpu)->pstate = pstate;
316
317 /* Reset system registers */
318 kvm_reset_sys_regs(vcpu);
319
320 /*
321 * Additional reset state handling that PSCI may have imposed on us.
322 * Must be done after all the sys_reg reset.
323 */
324 if (reset_state.reset) {
325 unsigned long target_pc = reset_state.pc;
326
327 /* Gracefully handle Thumb2 entry point */
328 if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
329 target_pc &= ~1UL;
330 vcpu_set_thumb(vcpu);
331 }
332
333 /* Propagate caller endianness */
334 if (reset_state.be)
335 kvm_vcpu_set_be(vcpu);
336
337 *vcpu_pc(vcpu) = target_pc;
338 vcpu_set_reg(vcpu, 0, reset_state.r0);
339 }
340
341 /* Reset timer */
342 ret = kvm_timer_vcpu_reset(vcpu);
343 out:
344 if (loaded)
345 kvm_arch_vcpu_load(vcpu, smp_processor_id());
346 preempt_enable();
347 return ret;
348 }
349
get_kvm_ipa_limit(void)350 u32 get_kvm_ipa_limit(void)
351 {
352 return kvm_ipa_limit;
353 }
354
kvm_set_ipa_limit(void)355 int kvm_set_ipa_limit(void)
356 {
357 unsigned int parange;
358 u64 mmfr0;
359
360 mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
361 parange = cpuid_feature_extract_unsigned_field(mmfr0,
362 ID_AA64MMFR0_EL1_PARANGE_SHIFT);
363 /*
364 * IPA size beyond 48 bits could not be supported
365 * on either 4K or 16K page size. Hence let's cap
366 * it to 48 bits, in case it's reported as larger
367 * on the system.
368 */
369 if (PAGE_SIZE != SZ_64K)
370 parange = min(parange, (unsigned int)ID_AA64MMFR0_EL1_PARANGE_48);
371
372 /*
373 * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
374 * Stage-2. If not, things will stop very quickly.
375 */
376 switch (cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_EL1_TGRAN_2_SHIFT)) {
377 case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_NONE:
378 kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
379 return -EINVAL;
380 case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_DEFAULT:
381 kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
382 break;
383 case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MAX:
384 kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
385 break;
386 default:
387 kvm_err("Unsupported value for TGRAN_2, giving up\n");
388 return -EINVAL;
389 }
390
391 kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange);
392 kvm_info("IPA Size Limit: %d bits%s\n", kvm_ipa_limit,
393 ((kvm_ipa_limit < KVM_PHYS_SHIFT) ?
394 " (Reduced IPA size, limited VM/VMM compatibility)" : ""));
395
396 return 0;
397 }
398
kvm_arm_setup_stage2(struct kvm * kvm,unsigned long type)399 int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
400 {
401 u64 mmfr0, mmfr1;
402 u32 phys_shift;
403
404 if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
405 return -EINVAL;
406
407 phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
408 if (phys_shift) {
409 if (phys_shift > kvm_ipa_limit ||
410 phys_shift < ARM64_MIN_PARANGE_BITS)
411 return -EINVAL;
412 } else {
413 phys_shift = KVM_PHYS_SHIFT;
414 if (phys_shift > kvm_ipa_limit) {
415 pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
416 current->comm);
417 return -EINVAL;
418 }
419 }
420
421 mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
422 mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
423 kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
424
425 return 0;
426 }
427