1 files changed, 315 insertions, 0 deletions
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
new file mode 100644
index 000000000..e5e741bff
--- /dev/null
+++ b/arch/arm64/kvm/handle_exit.c
@@ -0,0 +1,315 @@
+/*
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Derived from arch/arm/kvm/handle_exit.c:
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+
+#include <kvm/arm_psci.h>
+
+#include <asm/esr.h>
+#include <asm/exception.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_coproc.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_mmu.h>
+#include <asm/debug-monitors.h>
+#include <asm/traps.h>
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
+typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
+
+static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr)
+{
+	if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(NULL, esr))
+		kvm_inject_vabt(vcpu);
+}
+
+static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	int ret;
+
+	trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0),
+			    kvm_vcpu_hvc_get_imm(vcpu));
+	vcpu->stat.hvc_exit_stat++;
+
+	ret = kvm_hvc_call_handler(vcpu);
+	if (ret < 0) {
+		vcpu_set_reg(vcpu, 0, ~0UL);
+		return 1;
+	}
+
+	return ret;
+}
+
+static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	/*
+	 * "If an SMC instruction executed at Non-secure EL1 is
+	 * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
+	 * Trap exception, not a Secure Monitor Call exception [...]"
+	 *
+	 * We need to advance the PC after the trap, as it would
+	 * otherwise return to the same address...
+	 */
+	vcpu_set_reg(vcpu, 0, ~0UL);
+	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+	return 1;
+}
+
+/*
+ * Guest access to FP/ASIMD registers are routed to this handler only
+ * when the system doesn't support FP/ASIMD.
+ */
+static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	kvm_inject_undefined(vcpu);
+	return 1;
+}
+
+/**
+ * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
+ *		    instruction executed by a guest
+ *
+ * @vcpu:	the vcpu pointer
+ *
+ * WFE: Yield the CPU and come back to this vcpu when the scheduler
+ * decides to.
+ * WFI: Simply call kvm_vcpu_block(), which will halt execution of
+ * world-switches and schedule other host processes until there is an
+ * incoming IRQ or FIQ to the VM.
+ */
+static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
+		trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
+		vcpu->stat.wfe_exit_stat++;
+		kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
+	} else {
+		trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
+		vcpu->stat.wfi_exit_stat++;
+		kvm_vcpu_block(vcpu);
+		kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+	}
+
+	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+
+	return 1;
+}
+
+/**
+ * kvm_handle_guest_debug - handle a debug exception instruction
+ *
+ * @vcpu:	the vcpu pointer
+ * @run:	access to the kvm_run structure for results
+ *
+ * We route all debug exceptions through the same handler. If both the
+ * guest and host are using the same debug facilities it will be up to
+ * userspace to re-inject the correct exception for guest delivery.
+ *
+ * @return: 0 (while setting run->exit_reason), -1 for error
+ */
+static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	u32 hsr = kvm_vcpu_get_hsr(vcpu);
+	int ret = 0;
+
+	run->exit_reason = KVM_EXIT_DEBUG;
+	run->debug.arch.hsr = hsr;
+
+	switch (ESR_ELx_EC(hsr)) {
+	case ESR_ELx_EC_WATCHPT_LOW:
+		run->debug.arch.far = vcpu->arch.fault.far_el2;
+		/* fall through */
+	case ESR_ELx_EC_SOFTSTP_LOW:
+	case ESR_ELx_EC_BREAKPT_LOW:
+	case ESR_ELx_EC_BKPT32:
+	case ESR_ELx_EC_BRK64:
+		break;
+	default:
+		kvm_err("%s: un-handled case hsr: %#08x\n",
+			__func__, (unsigned int) hsr);
+		ret = -1;
+		break;
+	}
+
+	return ret;
+}
+
+static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	u32 hsr = kvm_vcpu_get_hsr(vcpu);
+
+	kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n",
+		      hsr, esr_get_class_string(hsr));
+
+	kvm_inject_undefined(vcpu);
+	return 1;
+}
+
+static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	/* Until SVE is supported for guests: */
+	kvm_inject_undefined(vcpu);
+	return 1;
+}
+
+static exit_handle_fn arm_exit_handlers[] = {
+	[0 ... ESR_ELx_EC_MAX]	= kvm_handle_unknown_ec,
+	[ESR_ELx_EC_WFx]	= kvm_handle_wfx,
+	[ESR_ELx_EC_CP15_32]	= kvm_handle_cp15_32,
+	[ESR_ELx_EC_CP15_64]	= kvm_handle_cp15_64,
+	[ESR_ELx_EC_CP14_MR]	= kvm_handle_cp14_32,
+	[ESR_ELx_EC_CP14_LS]	= kvm_handle_cp14_load_store,
+	[ESR_ELx_EC_CP14_64]	= kvm_handle_cp14_64,
+	[ESR_ELx_EC_HVC32]	= handle_hvc,
+	[ESR_ELx_EC_SMC32]	= handle_smc,
+	[ESR_ELx_EC_HVC64]	= handle_hvc,
+	[ESR_ELx_EC_SMC64]	= handle_smc,
+	[ESR_ELx_EC_SYS64]	= kvm_handle_sys_reg,
+	[ESR_ELx_EC_SVE]	= handle_sve,
+	[ESR_ELx_EC_IABT_LOW]	= kvm_handle_guest_abort,
+	[ESR_ELx_EC_DABT_LOW]	= kvm_handle_guest_abort,
+	[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
+	[ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
+	[ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
+	[ESR_ELx_EC_BKPT32]	= kvm_handle_guest_debug,
+	[ESR_ELx_EC_BRK64]	= kvm_handle_guest_debug,
+	[ESR_ELx_EC_FP_ASIMD]	= handle_no_fpsimd,
+};
+
+static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
+{
+	u32 hsr = kvm_vcpu_get_hsr(vcpu);
+	u8 hsr_ec = ESR_ELx_EC(hsr);
+
+	return arm_exit_handlers[hsr_ec];
+}
+
+/*
+ * We may be single-stepping an emulated instruction. If the emulation
+ * has been completed in the kernel, we can return to userspace with a
+ * KVM_EXIT_DEBUG, otherwise userspace needs to complete its
+ * emulation first.
+ */
+static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	int handled;
+
+	/*
+	 * See ARM ARM B1.14.1: "Hyp traps on instructions
+	 * that fail their condition code check"
+	 */
+	if (!kvm_condition_valid(vcpu)) {
+		kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+		handled = 1;
+	} else {
+		exit_handle_fn exit_handler;
+
+		exit_handler = kvm_get_exit_handler(vcpu);
+		handled = exit_handler(vcpu, run);
+	}
+
+	/*
+	 * kvm_arm_handle_step_debug() sets the exit_reason on the kvm_run
+	 * structure if we need to return to userspace.
+	 */
+	if (handled > 0 && kvm_arm_handle_step_debug(vcpu, run))
+		handled = 0;
+
+	return handled;
+}
+
+/*
+ * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
+ * proper exit to userspace.
+ */
+int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
+		       int exception_index)
+{
+	if (ARM_SERROR_PENDING(exception_index)) {
+		u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu));
+
+		/*
+		 * HVC/SMC already have an adjusted PC, which we need
+		 * to correct in order to return to after having
+		 * injected the SError.
+		 */
+		if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 ||
+		    hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) {
+			u32 adj =  kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
+			*vcpu_pc(vcpu) -= adj;
+		}
+
+		return 1;
+	}
+
+	exception_index = ARM_EXCEPTION_CODE(exception_index);
+
+	switch (exception_index) {
+	case ARM_EXCEPTION_IRQ:
+		return 1;
+	case ARM_EXCEPTION_EL1_SERROR:
+		/* We may still need to return for single-step */
+		if (!(*vcpu_cpsr(vcpu) & DBG_SPSR_SS)
+			&& kvm_arm_handle_step_debug(vcpu, run))
+			return 0;
+		else
+			return 1;
+	case ARM_EXCEPTION_TRAP:
+		return handle_trap_exceptions(vcpu, run);
+	case ARM_EXCEPTION_HYP_GONE:
+		/*
+		 * EL2 has been reset to the hyp-stub. This happens when a guest
+		 * is pre-empted by kvm_reboot()'s shutdown call.
+		 */
+		run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+		return 0;
+	default:
+		kvm_pr_unimpl("Unsupported exception type: %d",
+			      exception_index);
+		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+		return 0;
+	}
+}
+
+/* For exit types that need handling before we can be preempted */
+void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run,
+		       int exception_index)
+{
+	if (ARM_SERROR_PENDING(exception_index)) {
+		if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) {
+			u64 disr = kvm_vcpu_get_disr(vcpu);
+
+			kvm_handle_guest_serror(vcpu, disr_to_esr(disr));
+		} else {
+			kvm_inject_vabt(vcpu);
+		}
+
+		return;
+	}
+
+	exception_index = ARM_EXCEPTION_CODE(exception_index);
+
+	if (exception_index == ARM_EXCEPTION_EL1_SERROR)
+		kvm_handle_guest_serror(vcpu, kvm_vcpu_get_hsr(vcpu));
+}