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51e22c571f
commit 20e8175d24 upstream.
KVM doesn't follow the SMCCC when it comes to unimplemented calls,
and inject an UNDEF instead of returning an error. Since firmware
calls are now used for security mitigation, they are becoming more
common, and the undef is counter productive.
Instead, let's follow the SMCCC which states that -1 must be returned
to the caller when getting an unknown function number.
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
179 lines
4.8 KiB
C
179 lines
4.8 KiB
C
/*
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* Copyright (C) 2012 - Virtual Open Systems and Columbia University
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* Author: Christoffer Dall <c.dall@virtualopensystems.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <linux/kvm.h>
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#include <linux/kvm_host.h>
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#include <asm/kvm_emulate.h>
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#include <asm/kvm_coproc.h>
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#include <asm/kvm_mmu.h>
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#include <asm/kvm_psci.h>
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#include <trace/events/kvm.h>
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#include "trace.h"
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typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
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static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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int ret;
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trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
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kvm_vcpu_hvc_get_imm(vcpu));
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vcpu->stat.hvc_exit_stat++;
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ret = kvm_psci_call(vcpu);
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if (ret < 0) {
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vcpu_set_reg(vcpu, 0, ~0UL);
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return 1;
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}
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return ret;
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}
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static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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/*
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* "If an SMC instruction executed at Non-secure EL1 is
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* trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
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* Trap exception, not a Secure Monitor Call exception [...]"
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*
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* We need to advance the PC after the trap, as it would
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* otherwise return to the same address...
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*/
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vcpu_set_reg(vcpu, 0, ~0UL);
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kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
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return 1;
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}
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/**
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* kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
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* @vcpu: the vcpu pointer
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* @run: the kvm_run structure pointer
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*
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* WFE: Yield the CPU and come back to this vcpu when the scheduler
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* decides to.
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* WFI: Simply call kvm_vcpu_block(), which will halt execution of
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* world-switches and schedule other host processes until there is an
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* incoming IRQ or FIQ to the VM.
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*/
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static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
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trace_kvm_wfx(*vcpu_pc(vcpu), true);
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vcpu->stat.wfe_exit_stat++;
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kvm_vcpu_on_spin(vcpu);
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} else {
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trace_kvm_wfx(*vcpu_pc(vcpu), false);
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vcpu->stat.wfi_exit_stat++;
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kvm_vcpu_block(vcpu);
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}
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kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
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return 1;
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}
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static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
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{
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u32 hsr = kvm_vcpu_get_hsr(vcpu);
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kvm_pr_unimpl("Unknown exception class: hsr: %#08x\n",
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hsr);
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kvm_inject_undefined(vcpu);
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return 1;
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}
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static exit_handle_fn arm_exit_handlers[] = {
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[0 ... HSR_EC_MAX] = kvm_handle_unknown_ec,
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[HSR_EC_WFI] = kvm_handle_wfx,
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[HSR_EC_CP15_32] = kvm_handle_cp15_32,
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[HSR_EC_CP15_64] = kvm_handle_cp15_64,
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[HSR_EC_CP14_MR] = kvm_handle_cp14_32,
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[HSR_EC_CP14_LS] = kvm_handle_cp14_load_store,
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[HSR_EC_CP14_64] = kvm_handle_cp14_64,
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[HSR_EC_CP_0_13] = kvm_handle_cp_0_13_access,
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[HSR_EC_CP10_ID] = kvm_handle_cp10_id,
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[HSR_EC_HVC] = handle_hvc,
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[HSR_EC_SMC] = handle_smc,
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[HSR_EC_IABT] = kvm_handle_guest_abort,
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[HSR_EC_DABT] = kvm_handle_guest_abort,
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};
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static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
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{
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u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
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return arm_exit_handlers[hsr_ec];
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}
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/*
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* Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
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* proper exit to userspace.
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*/
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int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
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int exception_index)
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{
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exit_handle_fn exit_handler;
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if (ARM_ABORT_PENDING(exception_index)) {
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u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
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/*
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* HVC/SMC already have an adjusted PC, which we need
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* to correct in order to return to after having
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* injected the abort.
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*/
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if (hsr_ec == HSR_EC_HVC || hsr_ec == HSR_EC_SMC) {
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u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
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*vcpu_pc(vcpu) -= adj;
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}
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kvm_inject_vabt(vcpu);
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return 1;
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}
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exception_index = ARM_EXCEPTION_CODE(exception_index);
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switch (exception_index) {
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case ARM_EXCEPTION_IRQ:
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return 1;
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case ARM_EXCEPTION_HVC:
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/*
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* See ARM ARM B1.14.1: "Hyp traps on instructions
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* that fail their condition code check"
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*/
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if (!kvm_condition_valid(vcpu)) {
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kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
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return 1;
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}
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exit_handler = kvm_get_exit_handler(vcpu);
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return exit_handler(vcpu, run);
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case ARM_EXCEPTION_DATA_ABORT:
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kvm_inject_vabt(vcpu);
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return 1;
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default:
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kvm_pr_unimpl("Unsupported exception type: %d",
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exception_index);
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run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
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return 0;
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}
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}
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