arm64: KVM: fault injection into a guest

Implement the injection of a fault (undefined, data abort or
prefetch abort) into a 64bit guest.

Reviewed-by: Christopher Covington <cov@codeaurora.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 126 insertions, 0 deletions

diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
new file mode 100644
index 000000000000..54f656271266
--- /dev/null
+++ b/arch/arm64/kvm/inject_fault.c
@@ -0,0 +1,126 @@
+/*
+ * Fault injection for 64bit guests.
+ *
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Based on arch/arm/kvm/emulate.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_host.h>
+#include <asm/kvm_emulate.h>
+#include <asm/esr.h>
+
+#define PSTATE_FAULT_BITS_64    (PSR_MODE_EL1h | PSR_A_BIT | PSR_F_BIT | \
+                                 PSR_I_BIT | PSR_D_BIT)
+#define EL1_EXCEPT_SYNC_OFFSET  0x200
+
+static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
+{
+        unsigned long cpsr = *vcpu_cpsr(vcpu);
+        bool is_aarch32;
+        u32 esr = 0;
+
+        is_aarch32 = vcpu_mode_is_32bit(vcpu);
+
+        *vcpu_spsr(vcpu) = cpsr;
+        *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
+
+        *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+        *vcpu_pc(vcpu) = vcpu_sys_reg(vcpu, VBAR_EL1) + EL1_EXCEPT_SYNC_OFFSET;
+
+        vcpu_sys_reg(vcpu, FAR_EL1) = addr;
+
+        /*
+         * Build an {i,d}abort, depending on the level and the
+         * instruction set. Report an external synchronous abort.
+         */
+        if (kvm_vcpu_trap_il_is32bit(vcpu))
+                esr |= ESR_EL1_IL;
+
+        /*
+         * Here, the guest runs in AArch64 mode when in EL1. If we get
+         * an AArch32 fault, it means we managed to trap an EL0 fault.
+         */
+        if (is_aarch32 || (cpsr & PSR_MODE_MASK) == PSR_MODE_EL0t)
+                esr |= (ESR_EL1_EC_IABT_EL0 << ESR_EL1_EC_SHIFT);
+        else
+                esr |= (ESR_EL1_EC_IABT_EL1 << ESR_EL1_EC_SHIFT);
+
+        if (!is_iabt)
+                esr |= ESR_EL1_EC_DABT_EL0;
+
+        vcpu_sys_reg(vcpu, ESR_EL1) = esr | ESR_EL2_EC_xABT_xFSR_EXTABT;
+}
+
+static void inject_undef64(struct kvm_vcpu *vcpu)
+{
+        unsigned long cpsr = *vcpu_cpsr(vcpu);
+        u32 esr = (ESR_EL1_EC_UNKNOWN << ESR_EL1_EC_SHIFT);
+
+        *vcpu_spsr(vcpu) = cpsr;
+        *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
+
+        *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+        *vcpu_pc(vcpu) = vcpu_sys_reg(vcpu, VBAR_EL1) + EL1_EXCEPT_SYNC_OFFSET;
+
+        /*
+         * Build an unknown exception, depending on the instruction
+         * set.
+         */
+        if (kvm_vcpu_trap_il_is32bit(vcpu))
+                esr |= ESR_EL1_IL;
+
+        vcpu_sys_reg(vcpu, ESR_EL1) = esr;
+}
+
+/**
+ * kvm_inject_dabt - inject a data abort into the guest
+ * @vcpu: The VCPU to receive the undefined exception
+ * @addr: The address to report in the DFAR
+ *
+ * It is assumed that this code is called from the VCPU thread and that the
+ * VCPU therefore is not currently executing guest code.
+ */
+void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
+{
+        inject_abt64(vcpu, false, addr);
+}
+
+/**
+ * kvm_inject_pabt - inject a prefetch abort into the guest
+ * @vcpu: The VCPU to receive the undefined exception
+ * @addr: The address to report in the DFAR
+ *
+ * It is assumed that this code is called from the VCPU thread and that the
+ * VCPU therefore is not currently executing guest code.
+ */
+void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr)
+{
+        inject_abt64(vcpu, true, addr);
+}
+
+/**
+ * kvm_inject_undefined - inject an undefined instruction into the guest
+ *
+ * It is assumed that this code is called from the VCPU thread and that the
+ * VCPU therefore is not currently executing guest code.
+ */
+void kvm_inject_undefined(struct kvm_vcpu *vcpu)
+{
+        inject_undef64(vcpu);
+}