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_halt(), 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++;
107 * kvm_handle_guest_debug - handle a debug exception instruction
109 * @vcpu: the vcpu pointer
111 * We route all debug exceptions through the same handler. If both the
112 * guest and host are using the same debug facilities it will be up to
113 * userspace to re-inject the correct exception for guest delivery.
115 * @return: 0 (while setting vcpu->run->exit_reason)
117 static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu)
119 struct kvm_run *run = vcpu->run;
120 u32 esr = kvm_vcpu_get_esr(vcpu);
122 run->exit_reason = KVM_EXIT_DEBUG;
123 run->debug.arch.hsr = esr;
125 if (ESR_ELx_EC(esr) == ESR_ELx_EC_WATCHPT_LOW)
126 run->debug.arch.far = vcpu->arch.fault.far_el2;
131 static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu)
133 u32 esr = kvm_vcpu_get_esr(vcpu);
135 kvm_pr_unimpl("Unknown exception class: esr: %#08x -- %s\n",
136 esr, esr_get_class_string(esr));
138 kvm_inject_undefined(vcpu);
143 * Guest access to SVE registers should be routed to this handler only
144 * when the system doesn't support SVE.
146 static int handle_sve(struct kvm_vcpu *vcpu)
148 kvm_inject_undefined(vcpu);
153 * Guest usage of a ptrauth instruction (which the guest EL1 did not turn into
154 * a NOP). If we get here, it is that we didn't fixup ptrauth on exit, and all
155 * that we can do is give the guest an UNDEF.
157 static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu)
159 kvm_inject_undefined(vcpu);
163 static exit_handle_fn arm_exit_handlers[] = {
164 [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec,
165 [ESR_ELx_EC_WFx] = kvm_handle_wfx,
166 [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32,
167 [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64,
168 [ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32,
169 [ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store,
170 [ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64,
171 [ESR_ELx_EC_HVC32] = handle_hvc,
172 [ESR_ELx_EC_SMC32] = handle_smc,
173 [ESR_ELx_EC_HVC64] = handle_hvc,
174 [ESR_ELx_EC_SMC64] = handle_smc,
175 [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg,
176 [ESR_ELx_EC_SVE] = handle_sve,
177 [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort,
178 [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort,
179 [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
180 [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
181 [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
182 [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug,
183 [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug,
184 [ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd,
185 [ESR_ELx_EC_PAC] = kvm_handle_ptrauth,
188 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
190 u32 esr = kvm_vcpu_get_esr(vcpu);
191 u8 esr_ec = ESR_ELx_EC(esr);
193 return arm_exit_handlers[esr_ec];
197 * We may be single-stepping an emulated instruction. If the emulation
198 * has been completed in the kernel, we can return to userspace with a
199 * KVM_EXIT_DEBUG, otherwise userspace needs to complete its
202 static int handle_trap_exceptions(struct kvm_vcpu *vcpu)
207 * See ARM ARM B1.14.1: "Hyp traps on instructions
208 * that fail their condition code check"
210 if (!kvm_condition_valid(vcpu)) {
214 exit_handle_fn exit_handler;
216 exit_handler = kvm_get_exit_handler(vcpu);
217 handled = exit_handler(vcpu);
224 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
225 * proper exit to userspace.
227 int handle_exit(struct kvm_vcpu *vcpu, int exception_index)
229 struct kvm_run *run = vcpu->run;
231 if (ARM_SERROR_PENDING(exception_index)) {
233 * The SError is handled by handle_exit_early(). If the guest
234 * survives it will re-execute the original instruction.
239 exception_index = ARM_EXCEPTION_CODE(exception_index);
241 switch (exception_index) {
242 case ARM_EXCEPTION_IRQ:
244 case ARM_EXCEPTION_EL1_SERROR:
246 case ARM_EXCEPTION_TRAP:
247 return handle_trap_exceptions(vcpu);
248 case ARM_EXCEPTION_HYP_GONE:
250 * EL2 has been reset to the hyp-stub. This happens when a guest
251 * is pre-empted by kvm_reboot()'s shutdown call.
253 run->exit_reason = KVM_EXIT_FAIL_ENTRY;
255 case ARM_EXCEPTION_IL:
257 * We attempted an illegal exception return. Guest state must
258 * have been corrupted somehow. Give up.
260 run->exit_reason = KVM_EXIT_FAIL_ENTRY;
263 kvm_pr_unimpl("Unsupported exception type: %d",
265 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
270 /* For exit types that need handling before we can be preempted */
271 void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index)
273 if (ARM_SERROR_PENDING(exception_index)) {
274 if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) {
275 u64 disr = kvm_vcpu_get_disr(vcpu);
277 kvm_handle_guest_serror(vcpu, disr_to_esr(disr));
279 kvm_inject_vabt(vcpu);
285 exception_index = ARM_EXCEPTION_CODE(exception_index);
287 if (exception_index == ARM_EXCEPTION_EL1_SERROR)
288 kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu));
291 void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
292 u64 elr_virt, u64 elr_phys,
293 u64 par, uintptr_t vcpu,
294 u64 far, u64 hpfar) {
295 u64 elr_in_kimg = __phys_to_kimg(elr_phys);
296 u64 hyp_offset = elr_in_kimg - kaslr_offset() - elr_virt;
297 u64 mode = spsr & PSR_MODE_MASK;
300 * The nVHE hyp symbols are not included by kallsyms to avoid issues
301 * with aliasing. That means that the symbols cannot be printed with the
302 * "%pS" format specifier, so fall back to the vmlinux address if
303 * there's no better option.
305 if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) {
306 kvm_err("Invalid host exception to nVHE hyp!\n");
307 } else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
308 (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) {
309 const char *file = NULL;
310 unsigned int line = 0;
312 /* All hyp bugs, including warnings, are treated as fatal. */
313 if (!is_protected_kvm_enabled() ||
314 IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {
315 struct bug_entry *bug = find_bug(elr_in_kimg);
318 bug_get_file_line(bug, &file, &line);
322 kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
324 kvm_err("nVHE hyp BUG at: %016llx!\n", elr_virt + hyp_offset);
326 kvm_err("nVHE hyp panic at: %016llx!\n", elr_virt + hyp_offset);
330 * Hyp has panicked and we're going to handle that by panicking the
331 * kernel. The kernel offset will be revealed in the panic so we're
332 * also safe to reveal the hyp offset as a debugging aid for translating
333 * hyp VAs to vmlinux addresses.
335 kvm_err("Hyp Offset: 0x%llx\n", hyp_offset);
337 panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%016lx\n",
338 spsr, elr_virt, esr, far, hpfar, par, vcpu);