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-rw-r--r--arch/arm/kvm/emulate.c373
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diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
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+/*
+ * 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, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <linux/mm.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_emulate.h>
+#include <trace/events/kvm.h>
+
+#include "trace.h"
+
+#define VCPU_NR_MODES 6
+#define VCPU_REG_OFFSET_USR 0
+#define VCPU_REG_OFFSET_FIQ 1
+#define VCPU_REG_OFFSET_IRQ 2
+#define VCPU_REG_OFFSET_SVC 3
+#define VCPU_REG_OFFSET_ABT 4
+#define VCPU_REG_OFFSET_UND 5
+#define REG_OFFSET(_reg) \
+ (offsetof(struct kvm_regs, _reg) / sizeof(u32))
+
+#define USR_REG_OFFSET(_num) REG_OFFSET(usr_regs.uregs[_num])
+
+static const unsigned long vcpu_reg_offsets[VCPU_NR_MODES][15] = {
+ /* USR/SYS Registers */
+ [VCPU_REG_OFFSET_USR] = {
+ USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+ USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+ USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+ USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+ USR_REG_OFFSET(12), USR_REG_OFFSET(13), USR_REG_OFFSET(14),
+ },
+
+ /* FIQ Registers */
+ [VCPU_REG_OFFSET_FIQ] = {
+ USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+ USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+ USR_REG_OFFSET(6), USR_REG_OFFSET(7),
+ REG_OFFSET(fiq_regs[0]), /* r8 */
+ REG_OFFSET(fiq_regs[1]), /* r9 */
+ REG_OFFSET(fiq_regs[2]), /* r10 */
+ REG_OFFSET(fiq_regs[3]), /* r11 */
+ REG_OFFSET(fiq_regs[4]), /* r12 */
+ REG_OFFSET(fiq_regs[5]), /* r13 */
+ REG_OFFSET(fiq_regs[6]), /* r14 */
+ },
+
+ /* IRQ Registers */
+ [VCPU_REG_OFFSET_IRQ] = {
+ USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+ USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+ USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+ USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+ USR_REG_OFFSET(12),
+ REG_OFFSET(irq_regs[0]), /* r13 */
+ REG_OFFSET(irq_regs[1]), /* r14 */
+ },
+
+ /* SVC Registers */
+ [VCPU_REG_OFFSET_SVC] = {
+ USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+ USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+ USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+ USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+ USR_REG_OFFSET(12),
+ REG_OFFSET(svc_regs[0]), /* r13 */
+ REG_OFFSET(svc_regs[1]), /* r14 */
+ },
+
+ /* ABT Registers */
+ [VCPU_REG_OFFSET_ABT] = {
+ USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+ USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+ USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+ USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+ USR_REG_OFFSET(12),
+ REG_OFFSET(abt_regs[0]), /* r13 */
+ REG_OFFSET(abt_regs[1]), /* r14 */
+ },
+
+ /* UND Registers */
+ [VCPU_REG_OFFSET_UND] = {
+ USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+ USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+ USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+ USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+ USR_REG_OFFSET(12),
+ REG_OFFSET(und_regs[0]), /* r13 */
+ REG_OFFSET(und_regs[1]), /* r14 */
+ },
+};
+
+/*
+ * Return a pointer to the register number valid in the current mode of
+ * the virtual CPU.
+ */
+u32 *vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num)
+{
+ u32 *reg_array = (u32 *)&vcpu->arch.regs;
+ u32 mode = *vcpu_cpsr(vcpu) & MODE_MASK;
+
+ switch (mode) {
+ case USR_MODE...SVC_MODE:
+ mode &= ~MODE32_BIT; /* 0 ... 3 */
+ break;
+
+ case ABT_MODE:
+ mode = VCPU_REG_OFFSET_ABT;
+ break;
+
+ case UND_MODE:
+ mode = VCPU_REG_OFFSET_UND;
+ break;
+
+ case SYSTEM_MODE:
+ mode = VCPU_REG_OFFSET_USR;
+ break;
+
+ default:
+ BUG();
+ }
+
+ return reg_array + vcpu_reg_offsets[mode][reg_num];
+}
+
+/*
+ * Return the SPSR for the current mode of the virtual CPU.
+ */
+u32 *vcpu_spsr(struct kvm_vcpu *vcpu)
+{
+ u32 mode = *vcpu_cpsr(vcpu) & MODE_MASK;
+ switch (mode) {
+ case SVC_MODE:
+ return &vcpu->arch.regs.KVM_ARM_SVC_spsr;
+ case ABT_MODE:
+ return &vcpu->arch.regs.KVM_ARM_ABT_spsr;
+ case UND_MODE:
+ return &vcpu->arch.regs.KVM_ARM_UND_spsr;
+ case IRQ_MODE:
+ return &vcpu->arch.regs.KVM_ARM_IRQ_spsr;
+ case FIQ_MODE:
+ return &vcpu->arch.regs.KVM_ARM_FIQ_spsr;
+ default:
+ BUG();
+ }
+}
+
+/**
+ * kvm_handle_wfi - handle a wait-for-interrupts instruction executed by a guest
+ * @vcpu: the vcpu pointer
+ * @run: the kvm_run structure pointer
+ *
+ * Simply sets the wait_for_interrupts flag on the vcpu structure, which will
+ * halt execution of world-switches and schedule other host processes until
+ * there is an incoming IRQ or FIQ to the VM.
+ */
+int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ trace_kvm_wfi(*vcpu_pc(vcpu));
+ kvm_vcpu_block(vcpu);
+ return 1;
+}
+
+/**
+ * adjust_itstate - adjust ITSTATE when emulating instructions in IT-block
+ * @vcpu: The VCPU pointer
+ *
+ * When exceptions occur while instructions are executed in Thumb IF-THEN
+ * blocks, the ITSTATE field of the CPSR is not advanved (updated), so we have
+ * to do this little bit of work manually. The fields map like this:
+ *
+ * IT[7:0] -> CPSR[26:25],CPSR[15:10]
+ */
+static void kvm_adjust_itstate(struct kvm_vcpu *vcpu)
+{
+ unsigned long itbits, cond;
+ unsigned long cpsr = *vcpu_cpsr(vcpu);
+ bool is_arm = !(cpsr & PSR_T_BIT);
+
+ BUG_ON(is_arm && (cpsr & PSR_IT_MASK));
+
+ if (!(cpsr & PSR_IT_MASK))
+ return;
+
+ cond = (cpsr & 0xe000) >> 13;
+ itbits = (cpsr & 0x1c00) >> (10 - 2);
+ itbits |= (cpsr & (0x3 << 25)) >> 25;
+
+ /* Perform ITAdvance (see page A-52 in ARM DDI 0406C) */
+ if ((itbits & 0x7) == 0)
+ itbits = cond = 0;
+ else
+ itbits = (itbits << 1) & 0x1f;
+
+ cpsr &= ~PSR_IT_MASK;
+ cpsr |= cond << 13;
+ cpsr |= (itbits & 0x1c) << (10 - 2);
+ cpsr |= (itbits & 0x3) << 25;
+ *vcpu_cpsr(vcpu) = cpsr;
+}
+
+/**
+ * kvm_skip_instr - skip a trapped instruction and proceed to the next
+ * @vcpu: The vcpu pointer
+ */
+void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr)
+{
+ bool is_thumb;
+
+ is_thumb = !!(*vcpu_cpsr(vcpu) & PSR_T_BIT);
+ if (is_thumb && !is_wide_instr)
+ *vcpu_pc(vcpu) += 2;
+ else
+ *vcpu_pc(vcpu) += 4;
+ kvm_adjust_itstate(vcpu);
+}
+
+
+/******************************************************************************
+ * Inject exceptions into the guest
+ */
+
+static u32 exc_vector_base(struct kvm_vcpu *vcpu)
+{
+ u32 sctlr = vcpu->arch.cp15[c1_SCTLR];
+ u32 vbar = vcpu->arch.cp15[c12_VBAR];
+
+ if (sctlr & SCTLR_V)
+ return 0xffff0000;
+ else /* always have security exceptions */
+ return vbar;
+}
+
+/**
+ * kvm_inject_undefined - inject an undefined exception into the guest
+ * @vcpu: The VCPU to receive the undefined exception
+ *
+ * It is assumed that this code is called from the VCPU thread and that the
+ * VCPU therefore is not currently executing guest code.
+ *
+ * Modelled after TakeUndefInstrException() pseudocode.
+ */
+void kvm_inject_undefined(struct kvm_vcpu *vcpu)
+{
+ u32 new_lr_value;
+ u32 new_spsr_value;
+ u32 cpsr = *vcpu_cpsr(vcpu);
+ u32 sctlr = vcpu->arch.cp15[c1_SCTLR];
+ bool is_thumb = (cpsr & PSR_T_BIT);
+ u32 vect_offset = 4;
+ u32 return_offset = (is_thumb) ? 2 : 4;
+
+ new_spsr_value = cpsr;
+ new_lr_value = *vcpu_pc(vcpu) - return_offset;
+
+ *vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | UND_MODE;
+ *vcpu_cpsr(vcpu) |= PSR_I_BIT;
+ *vcpu_cpsr(vcpu) &= ~(PSR_IT_MASK | PSR_J_BIT | PSR_E_BIT | PSR_T_BIT);
+
+ if (sctlr & SCTLR_TE)
+ *vcpu_cpsr(vcpu) |= PSR_T_BIT;
+ if (sctlr & SCTLR_EE)
+ *vcpu_cpsr(vcpu) |= PSR_E_BIT;
+
+ /* Note: These now point to UND banked copies */
+ *vcpu_spsr(vcpu) = cpsr;
+ *vcpu_reg(vcpu, 14) = new_lr_value;
+
+ /* Branch to exception vector */
+ *vcpu_pc(vcpu) = exc_vector_base(vcpu) + vect_offset;
+}
+
+/*
+ * Modelled after TakeDataAbortException() and TakePrefetchAbortException
+ * pseudocode.
+ */
+static void inject_abt(struct kvm_vcpu *vcpu, bool is_pabt, unsigned long addr)
+{
+ u32 new_lr_value;
+ u32 new_spsr_value;
+ u32 cpsr = *vcpu_cpsr(vcpu);
+ u32 sctlr = vcpu->arch.cp15[c1_SCTLR];
+ bool is_thumb = (cpsr & PSR_T_BIT);
+ u32 vect_offset;
+ u32 return_offset = (is_thumb) ? 4 : 0;
+ bool is_lpae;
+
+ new_spsr_value = cpsr;
+ new_lr_value = *vcpu_pc(vcpu) + return_offset;
+
+ *vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | ABT_MODE;
+ *vcpu_cpsr(vcpu) |= PSR_I_BIT | PSR_A_BIT;
+ *vcpu_cpsr(vcpu) &= ~(PSR_IT_MASK | PSR_J_BIT | PSR_E_BIT | PSR_T_BIT);
+
+ if (sctlr & SCTLR_TE)
+ *vcpu_cpsr(vcpu) |= PSR_T_BIT;
+ if (sctlr & SCTLR_EE)
+ *vcpu_cpsr(vcpu) |= PSR_E_BIT;
+
+ /* Note: These now point to ABT banked copies */
+ *vcpu_spsr(vcpu) = cpsr;
+ *vcpu_reg(vcpu, 14) = new_lr_value;
+
+ if (is_pabt)
+ vect_offset = 12;
+ else
+ vect_offset = 16;
+
+ /* Branch to exception vector */
+ *vcpu_pc(vcpu) = exc_vector_base(vcpu) + vect_offset;
+
+ if (is_pabt) {
+ /* Set DFAR and DFSR */
+ vcpu->arch.cp15[c6_IFAR] = addr;
+ is_lpae = (vcpu->arch.cp15[c2_TTBCR] >> 31);
+ /* Always give debug fault for now - should give guest a clue */
+ if (is_lpae)
+ vcpu->arch.cp15[c5_IFSR] = 1 << 9 | 0x22;
+ else
+ vcpu->arch.cp15[c5_IFSR] = 2;
+ } else { /* !iabt */
+ /* Set DFAR and DFSR */
+ vcpu->arch.cp15[c6_DFAR] = addr;
+ is_lpae = (vcpu->arch.cp15[c2_TTBCR] >> 31);
+ /* Always give debug fault for now - should give guest a clue */
+ if (is_lpae)
+ vcpu->arch.cp15[c5_DFSR] = 1 << 9 | 0x22;
+ else
+ vcpu->arch.cp15[c5_DFSR] = 2;
+ }
+
+}
+
+/**
+ * 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_abt(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_abt(vcpu, true, addr);
+}