1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2015 - ARM Ltd
4 * Author: Marc Zyngier <marc.zyngier@arm.com>
5 */
6
7#include <hyp/switch.h>
8#include <hyp/sysreg-sr.h>
9
10#include <linux/arm-smccc.h>
11#include <linux/kvm_host.h>
12#include <linux/types.h>
13#include <linux/jump_label.h>
14#include <uapi/linux/psci.h>
15
16#include <kvm/arm_psci.h>
17
18#include <asm/barrier.h>
19#include <asm/cpufeature.h>
20#include <asm/kprobes.h>
21#include <asm/kvm_asm.h>
22#include <asm/kvm_emulate.h>
23#include <asm/kvm_hyp.h>
24#include <asm/kvm_mmu.h>
25#include <asm/fpsimd.h>
26#include <asm/debug-monitors.h>
27#include <asm/processor.h>
28
29#include <nvhe/fixed_config.h>
30#include <nvhe/mem_protect.h>
31
32/* Non-VHE specific context */
33DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
34DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
35DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
36
37extern void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
38
39static void __activate_traps(struct kvm_vcpu *vcpu)
40{
41	u64 val;
42
43	___activate_traps(vcpu);
44	__activate_traps_common(vcpu);
45
46	val = vcpu->arch.cptr_el2;
47	val |= CPTR_EL2_TAM;	/* Same bit irrespective of E2H */
48	val |= has_hvhe() ? CPACR_EL1_TTA : CPTR_EL2_TTA;
49	if (cpus_have_final_cap(ARM64_SME)) {
50		if (has_hvhe())
51			val &= ~(CPACR_EL1_SMEN_EL1EN | CPACR_EL1_SMEN_EL0EN);
52		else
53			val |= CPTR_EL2_TSM;
54	}
55
56	if (!guest_owns_fp_regs(vcpu)) {
57		if (has_hvhe())
58			val &= ~(CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN |
59				 CPACR_EL1_ZEN_EL0EN | CPACR_EL1_ZEN_EL1EN);
60		else
61			val |= CPTR_EL2_TFP | CPTR_EL2_TZ;
62
63		__activate_traps_fpsimd32(vcpu);
64	}
65
66	kvm_write_cptr_el2(val);
67	write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el2);
68
69	if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
70		struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
71
72		isb();
73		/*
74		 * At this stage, and thanks to the above isb(), S2 is
75		 * configured and enabled. We can now restore the guest's S1
76		 * configuration: SCTLR, and only then TCR.
77		 */
78		write_sysreg_el1(ctxt_sys_reg(ctxt, SCTLR_EL1),	SYS_SCTLR);
79		isb();
80		write_sysreg_el1(ctxt_sys_reg(ctxt, TCR_EL1),	SYS_TCR);
81	}
82}
83
84static void __deactivate_traps(struct kvm_vcpu *vcpu)
85{
86	extern char __kvm_hyp_host_vector[];
87
88	___deactivate_traps(vcpu);
89
90	if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
91		u64 val;
92
93		/*
94		 * Set the TCR and SCTLR registers in the exact opposite
95		 * sequence as __activate_traps (first prevent walks,
96		 * then force the MMU on). A generous sprinkling of isb()
97		 * ensure that things happen in this exact order.
98		 */
99		val = read_sysreg_el1(SYS_TCR);
100		write_sysreg_el1(val | TCR_EPD1_MASK | TCR_EPD0_MASK, SYS_TCR);
101		isb();
102		val = read_sysreg_el1(SYS_SCTLR);
103		write_sysreg_el1(val | SCTLR_ELx_M, SYS_SCTLR);
104		isb();
105	}
106
107	__deactivate_traps_common(vcpu);
108
109	write_sysreg(this_cpu_ptr(&kvm_init_params)->hcr_el2, hcr_el2);
110
111	kvm_reset_cptr_el2(vcpu);
112	write_sysreg(__kvm_hyp_host_vector, vbar_el2);
113}
114
115/* Save VGICv3 state on non-VHE systems */
116static void __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
117{
118	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
119		__vgic_v3_save_state(&vcpu->arch.vgic_cpu.vgic_v3);
120		__vgic_v3_deactivate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
121	}
122}
123
124/* Restore VGICv3 state on non-VHE systems */
125static void __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
126{
127	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
128		__vgic_v3_activate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
129		__vgic_v3_restore_state(&vcpu->arch.vgic_cpu.vgic_v3);
130	}
131}
132
133/*
134 * Disable host events, enable guest events
135 */
136#ifdef CONFIG_HW_PERF_EVENTS
137static bool __pmu_switch_to_guest(struct kvm_vcpu *vcpu)
138{
139	struct kvm_pmu_events *pmu = &vcpu->arch.pmu.events;
140
141	if (pmu->events_host)
142		write_sysreg(pmu->events_host, pmcntenclr_el0);
143
144	if (pmu->events_guest)
145		write_sysreg(pmu->events_guest, pmcntenset_el0);
146
147	return (pmu->events_host || pmu->events_guest);
148}
149
150/*
151 * Disable guest events, enable host events
152 */
153static void __pmu_switch_to_host(struct kvm_vcpu *vcpu)
154{
155	struct kvm_pmu_events *pmu = &vcpu->arch.pmu.events;
156
157	if (pmu->events_guest)
158		write_sysreg(pmu->events_guest, pmcntenclr_el0);
159
160	if (pmu->events_host)
161		write_sysreg(pmu->events_host, pmcntenset_el0);
162}
163#else
164#define __pmu_switch_to_guest(v)	({ false; })
165#define __pmu_switch_to_host(v)		do {} while (0)
166#endif
167
168/*
169 * Handler for protected VM MSR, MRS or System instruction execution in AArch64.
170 *
171 * Returns true if the hypervisor has handled the exit, and control should go
172 * back to the guest, or false if it hasn't.
173 */
174static bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code)
175{
176	/*
177	 * Make sure we handle the exit for workarounds and ptrauth
178	 * before the pKVM handling, as the latter could decide to
179	 * UNDEF.
180	 */
181	return (kvm_hyp_handle_sysreg(vcpu, exit_code) ||
182		kvm_handle_pvm_sysreg(vcpu, exit_code));
183}
184
185static const exit_handler_fn hyp_exit_handlers[] = {
186	[0 ... ESR_ELx_EC_MAX]		= NULL,
187	[ESR_ELx_EC_CP15_32]		= kvm_hyp_handle_cp15_32,
188	[ESR_ELx_EC_SYS64]		= kvm_hyp_handle_sysreg,
189	[ESR_ELx_EC_SVE]		= kvm_hyp_handle_fpsimd,
190	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,
191	[ESR_ELx_EC_IABT_LOW]		= kvm_hyp_handle_iabt_low,
192	[ESR_ELx_EC_DABT_LOW]		= kvm_hyp_handle_dabt_low,
193	[ESR_ELx_EC_WATCHPT_LOW]	= kvm_hyp_handle_watchpt_low,
194	[ESR_ELx_EC_PAC]		= kvm_hyp_handle_ptrauth,
195	[ESR_ELx_EC_MOPS]		= kvm_hyp_handle_mops,
196};
197
198static const exit_handler_fn pvm_exit_handlers[] = {
199	[0 ... ESR_ELx_EC_MAX]		= NULL,
200	[ESR_ELx_EC_SYS64]		= kvm_handle_pvm_sys64,
201	[ESR_ELx_EC_SVE]		= kvm_handle_pvm_restricted,
202	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,
203	[ESR_ELx_EC_IABT_LOW]		= kvm_hyp_handle_iabt_low,
204	[ESR_ELx_EC_DABT_LOW]		= kvm_hyp_handle_dabt_low,
205	[ESR_ELx_EC_WATCHPT_LOW]	= kvm_hyp_handle_watchpt_low,
206	[ESR_ELx_EC_PAC]		= kvm_hyp_handle_ptrauth,
207	[ESR_ELx_EC_MOPS]		= kvm_hyp_handle_mops,
208};
209
210static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu)
211{
212	if (unlikely(kvm_vm_is_protected(kern_hyp_va(vcpu->kvm))))
213		return pvm_exit_handlers;
214
215	return hyp_exit_handlers;
216}
217
218/*
219 * Some guests (e.g., protected VMs) are not be allowed to run in AArch32.
220 * The ARMv8 architecture does not give the hypervisor a mechanism to prevent a
221 * guest from dropping to AArch32 EL0 if implemented by the CPU. If the
222 * hypervisor spots a guest in such a state ensure it is handled, and don't
223 * trust the host to spot or fix it.  The check below is based on the one in
224 * kvm_arch_vcpu_ioctl_run().
225 *
226 * Returns false if the guest ran in AArch32 when it shouldn't have, and
227 * thus should exit to the host, or true if a the guest run loop can continue.
228 */
229static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code)
230{
231	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
232
233	if (kvm_vm_is_protected(kvm) && vcpu_mode_is_32bit(vcpu)) {
234		/*
235		 * As we have caught the guest red-handed, decide that it isn't
236		 * fit for purpose anymore by making the vcpu invalid. The VMM
237		 * can try and fix it by re-initializing the vcpu with
238		 * KVM_ARM_VCPU_INIT, however, this is likely not possible for
239		 * protected VMs.
240		 */
241		vcpu_clear_flag(vcpu, VCPU_INITIALIZED);
242		*exit_code &= BIT(ARM_EXIT_WITH_SERROR_BIT);
243		*exit_code |= ARM_EXCEPTION_IL;
244	}
245}
246
247/* Switch to the guest for legacy non-VHE systems */
248int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
249{
250	struct kvm_cpu_context *host_ctxt;
251	struct kvm_cpu_context *guest_ctxt;
252	struct kvm_s2_mmu *mmu;
253	bool pmu_switch_needed;
254	u64 exit_code;
255
256	/*
257	 * Having IRQs masked via PMR when entering the guest means the GIC
258	 * will not signal the CPU of interrupts of lower priority, and the
259	 * only way to get out will be via guest exceptions.
260	 * Naturally, we want to avoid this.
261	 */
262	if (system_uses_irq_prio_masking()) {
263		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
264		pmr_sync();
265	}
266
267	host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
268	host_ctxt->__hyp_running_vcpu = vcpu;
269	guest_ctxt = &vcpu->arch.ctxt;
270
271	pmu_switch_needed = __pmu_switch_to_guest(vcpu);
272
273	__sysreg_save_state_nvhe(host_ctxt);
274	/*
275	 * We must flush and disable the SPE buffer for nVHE, as
276	 * the translation regime(EL1&0) is going to be loaded with
277	 * that of the guest. And we must do this before we change the
278	 * translation regime to EL2 (via MDCR_EL2_E2PB == 0) and
279	 * before we load guest Stage1.
280	 */
281	__debug_save_host_buffers_nvhe(vcpu);
282
283	/*
284	 * We're about to restore some new MMU state. Make sure
285	 * ongoing page-table walks that have started before we
286	 * trapped to EL2 have completed. This also synchronises the
287	 * above disabling of SPE and TRBE.
288	 *
289	 * See DDI0487I.a D8.1.5 "Out-of-context translation regimes",
290	 * rule R_LFHQG and subsequent information statements.
291	 */
292	dsb(nsh);
293
294	__kvm_adjust_pc(vcpu);
295
296	/*
297	 * We must restore the 32-bit state before the sysregs, thanks
298	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
299	 *
300	 * Also, and in order to be able to deal with erratum #1319537 (A57)
301	 * and #1319367 (A72), we must ensure that all VM-related sysreg are
302	 * restored before we enable S2 translation.
303	 */
304	__sysreg32_restore_state(vcpu);
305	__sysreg_restore_state_nvhe(guest_ctxt);
306
307	mmu = kern_hyp_va(vcpu->arch.hw_mmu);
308	__load_stage2(mmu, kern_hyp_va(mmu->arch));
309	__activate_traps(vcpu);
310
311	__hyp_vgic_restore_state(vcpu);
312	__timer_enable_traps(vcpu);
313
314	__debug_switch_to_guest(vcpu);
315
316	do {
317		/* Jump in the fire! */
318		exit_code = __guest_enter(vcpu);
319
320		/* And we're baaack! */
321	} while (fixup_guest_exit(vcpu, &exit_code));
322
323	__sysreg_save_state_nvhe(guest_ctxt);
324	__sysreg32_save_state(vcpu);
325	__timer_disable_traps(vcpu);
326	__hyp_vgic_save_state(vcpu);
327
328	/*
329	 * Same thing as before the guest run: we're about to switch
330	 * the MMU context, so let's make sure we don't have any
331	 * ongoing EL1&0 translations.
332	 */
333	dsb(nsh);
334
335	__deactivate_traps(vcpu);
336	__load_host_stage2();
337
338	__sysreg_restore_state_nvhe(host_ctxt);
339
340	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED)
341		__fpsimd_save_fpexc32(vcpu);
342
343	__debug_switch_to_host(vcpu);
344	/*
345	 * This must come after restoring the host sysregs, since a non-VHE
346	 * system may enable SPE here and make use of the TTBRs.
347	 */
348	__debug_restore_host_buffers_nvhe(vcpu);
349
350	if (pmu_switch_needed)
351		__pmu_switch_to_host(vcpu);
352
353	/* Returning to host will clear PSR.I, remask PMR if needed */
354	if (system_uses_irq_prio_masking())
355		gic_write_pmr(GIC_PRIO_IRQOFF);
356
357	host_ctxt->__hyp_running_vcpu = NULL;
358
359	return exit_code;
360}
361
362asmlinkage void __noreturn hyp_panic(void)
363{
364	u64 spsr = read_sysreg_el2(SYS_SPSR);
365	u64 elr = read_sysreg_el2(SYS_ELR);
366	u64 par = read_sysreg_par();
367	struct kvm_cpu_context *host_ctxt;
368	struct kvm_vcpu *vcpu;
369
370	host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
371	vcpu = host_ctxt->__hyp_running_vcpu;
372
373	if (vcpu) {
374		__timer_disable_traps(vcpu);
375		__deactivate_traps(vcpu);
376		__load_host_stage2();
377		__sysreg_restore_state_nvhe(host_ctxt);
378	}
379
380	/* Prepare to dump kvm nvhe hyp stacktrace */
381	kvm_nvhe_prepare_backtrace((unsigned long)__builtin_frame_address(0),
382				   _THIS_IP_);
383
384	__hyp_do_panic(host_ctxt, spsr, elr, par);
385	unreachable();
386}
387
388asmlinkage void __noreturn hyp_panic_bad_stack(void)
389{
390	hyp_panic();
391}
392
393asmlinkage void kvm_unexpected_el2_exception(void)
394{
395	__kvm_unexpected_el2_exception();
396}
397