1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012,2013 - ARM Ltd
4 * Author: Marc Zyngier <marc.zyngier@arm.com>
6 * Derived from arch/arm/kvm/handle_exit.c:
7 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
8 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
11 #include <linux/kvm.h>
12 #include <linux/kvm_host.h>
15 #include <asm/exception.h>
16 #include <asm/kvm_asm.h>
17 #include <asm/kvm_emulate.h>
18 #include <asm/kvm_mmu.h>
19 #include <asm/debug-monitors.h>
20 #include <asm/traps.h>
22 #include <kvm/arm_hypercalls.h>
24 #define CREATE_TRACE_POINTS
25 #include "trace_handle_exit.h"
27 typedef int (*exit_handle_fn)(struct kvm_vcpu *);
29 static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr)
31 if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(NULL, esr))
32 kvm_inject_vabt(vcpu);
35 static int handle_hvc(struct kvm_vcpu *vcpu)
39 trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0),
40 kvm_vcpu_hvc_get_imm(vcpu));
41 vcpu->stat.hvc_exit_stat++;
43 ret = kvm_hvc_call_handler(vcpu);
45 vcpu_set_reg(vcpu, 0, ~0UL);
52 static int handle_smc(struct kvm_vcpu *vcpu)
55 * "If an SMC instruction executed at Non-secure EL1 is
56 * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
57 * Trap exception, not a Secure Monitor Call exception [...]"
59 * We need to advance the PC after the trap, as it would
60 * otherwise return to the same address...
62 vcpu_set_reg(vcpu, 0, ~0UL);
68 * Guest access to FP/ASIMD registers are routed to this handler only
69 * when the system doesn't support FP/ASIMD.
71 static int handle_no_fpsimd(struct kvm_vcpu *vcpu)
73 kvm_inject_undefined(vcpu);
78 * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
79 * instruction executed by a guest
81 * @vcpu: the vcpu pointer
83 * WFE: Yield the CPU and come back to this vcpu when the scheduler
85 * WFI: Simply call kvm_vcpu_block(), which will halt execution of
86 * world-switches and schedule other host processes until there is an
87 * incoming IRQ or FIQ to the VM.
89 static int kvm_handle_wfx(struct kvm_vcpu *vcpu)
91 if (kvm_vcpu_get_esr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
92 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
93 vcpu->stat.wfe_exit_stat++;
94 kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
96 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
97 vcpu->stat.wfi_exit_stat++;
99 kvm_clear_request(KVM_REQ_UNHALT, vcpu);
108 * kvm_handle_guest_debug - handle a debug exception instruction
110 * @vcpu: the vcpu pointer
112 * We route all debug exceptions through the same handler. If both the
113 * guest and host are using the same debug facilities it will be up to
114 * userspace to re-inject the correct exception for guest delivery.
116 * @return: 0 (while setting vcpu->run->exit_reason), -1 for error
118 static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu)
120 struct kvm_run *run = vcpu->run;
121 u32 esr = kvm_vcpu_get_esr(vcpu);
124 run->exit_reason = KVM_EXIT_DEBUG;
125 run->debug.arch.hsr = esr;
127 switch (ESR_ELx_EC(esr)) {
128 case ESR_ELx_EC_WATCHPT_LOW:
129 run->debug.arch.far = vcpu->arch.fault.far_el2;
131 case ESR_ELx_EC_SOFTSTP_LOW:
132 case ESR_ELx_EC_BREAKPT_LOW:
133 case ESR_ELx_EC_BKPT32:
134 case ESR_ELx_EC_BRK64:
137 kvm_err("%s: un-handled case esr: %#08x\n",
138 __func__, (unsigned int) esr);
146 static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu)
148 u32 esr = kvm_vcpu_get_esr(vcpu);
150 kvm_pr_unimpl("Unknown exception class: esr: %#08x -- %s\n",
151 esr, esr_get_class_string(esr));
153 kvm_inject_undefined(vcpu);
157 static int handle_sve(struct kvm_vcpu *vcpu)
159 /* Until SVE is supported for guests: */
160 kvm_inject_undefined(vcpu);
165 * Guest usage of a ptrauth instruction (which the guest EL1 did not turn into
166 * a NOP). If we get here, it is that we didn't fixup ptrauth on exit, and all
167 * that we can do is give the guest an UNDEF.
169 static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu)
171 kvm_inject_undefined(vcpu);
175 static exit_handle_fn arm_exit_handlers[] = {
176 [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec,
177 [ESR_ELx_EC_WFx] = kvm_handle_wfx,
178 [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32,
179 [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64,
180 [ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32,
181 [ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store,
182 [ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64,
183 [ESR_ELx_EC_HVC32] = handle_hvc,
184 [ESR_ELx_EC_SMC32] = handle_smc,
185 [ESR_ELx_EC_HVC64] = handle_hvc,
186 [ESR_ELx_EC_SMC64] = handle_smc,
187 [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg,
188 [ESR_ELx_EC_SVE] = handle_sve,
189 [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort,
190 [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort,
191 [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
192 [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
193 [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
194 [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug,
195 [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug,
196 [ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd,
197 [ESR_ELx_EC_PAC] = kvm_handle_ptrauth,
200 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
202 u32 esr = kvm_vcpu_get_esr(vcpu);
203 u8 esr_ec = ESR_ELx_EC(esr);
205 return arm_exit_handlers[esr_ec];
209 * We may be single-stepping an emulated instruction. If the emulation
210 * has been completed in the kernel, we can return to userspace with a
211 * KVM_EXIT_DEBUG, otherwise userspace needs to complete its
214 static int handle_trap_exceptions(struct kvm_vcpu *vcpu)
219 * See ARM ARM B1.14.1: "Hyp traps on instructions
220 * that fail their condition code check"
222 if (!kvm_condition_valid(vcpu)) {
226 exit_handle_fn exit_handler;
228 exit_handler = kvm_get_exit_handler(vcpu);
229 handled = exit_handler(vcpu);
236 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
237 * proper exit to userspace.
239 int handle_exit(struct kvm_vcpu *vcpu, int exception_index)
241 struct kvm_run *run = vcpu->run;
243 exception_index = ARM_EXCEPTION_CODE(exception_index);
245 switch (exception_index) {
246 case ARM_EXCEPTION_IRQ:
248 case ARM_EXCEPTION_EL1_SERROR:
250 case ARM_EXCEPTION_TRAP:
251 return handle_trap_exceptions(vcpu);
252 case ARM_EXCEPTION_HYP_GONE:
254 * EL2 has been reset to the hyp-stub. This happens when a guest
255 * is pre-empted by kvm_reboot()'s shutdown call.
257 run->exit_reason = KVM_EXIT_FAIL_ENTRY;
259 case ARM_EXCEPTION_IL:
261 * We attempted an illegal exception return. Guest state must
262 * have been corrupted somehow. Give up.
264 run->exit_reason = KVM_EXIT_FAIL_ENTRY;
267 kvm_pr_unimpl("Unsupported exception type: %d",
269 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
274 /* For exit types that need handling before we can be preempted */
275 void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index)
277 if (ARM_SERROR_PENDING(exception_index)) {
278 if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) {
279 u64 disr = kvm_vcpu_get_disr(vcpu);
281 kvm_handle_guest_serror(vcpu, disr_to_esr(disr));
283 kvm_inject_vabt(vcpu);
289 exception_index = ARM_EXCEPTION_CODE(exception_index);
291 if (exception_index == ARM_EXCEPTION_EL1_SERROR)
292 kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu));
295 void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr, u64 elr,
296 u64 par, uintptr_t vcpu,
297 u64 far, u64 hpfar) {
298 u64 elr_in_kimg = __phys_to_kimg(__hyp_pa(elr));
299 u64 hyp_offset = elr_in_kimg - kaslr_offset() - elr;
300 u64 mode = spsr & PSR_MODE_MASK;
303 * The nVHE hyp symbols are not included by kallsyms to avoid issues
304 * with aliasing. That means that the symbols cannot be printed with the
305 * "%pS" format specifier, so fall back to the vmlinux address if
306 * there's no better option.
308 if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) {
309 kvm_err("Invalid host exception to nVHE hyp!\n");
310 } else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
311 (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) {
312 struct bug_entry *bug = find_bug(elr_in_kimg);
313 const char *file = NULL;
314 unsigned int line = 0;
316 /* All hyp bugs, including warnings, are treated as fatal. */
318 bug_get_file_line(bug, &file, &line);
321 kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
323 kvm_err("nVHE hyp BUG at: %016llx!\n", elr + hyp_offset);
325 kvm_err("nVHE hyp panic at: %016llx!\n", elr + hyp_offset);
329 * Hyp has panicked and we're going to handle that by panicking the
330 * kernel. The kernel offset will be revealed in the panic so we're
331 * also safe to reveal the hyp offset as a debugging aid for translating
332 * hyp VAs to vmlinux addresses.
334 kvm_err("Hyp Offset: 0x%llx\n", hyp_offset);
336 panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%016lx\n",
337 spsr, elr, esr, far, hpfar, par, vcpu);