diff options
| author | James Hogan <james.hogan@imgtec.com> | 2015-02-06 16:03:57 +0000 |
|---|---|---|
| committer | James Hogan <james.hogan@imgtec.com> | 2015-03-27 21:25:07 +0000 |
| commit | 0a5604272d80c985f87de959f0bb7e36fd53d3c7 (patch) | |
| tree | 391bbee989a6ab6ab22d7b4b32a0b7850602d5be /arch/mips/kvm/trap_emul.c | |
| parent | 64bedffe496820dbb6b53302d80dd0f04db33d8e (diff) | |
MIPS: KVM: Handle TRAP exceptions from guest kernel
Trap instructions are used by Linux to implement BUG_ON(), however KVM
doesn't pass trap exceptions on to the guest if they occur in guest
kernel mode, instead triggering an internal error "Exception Code: 13,
not yet handled". The guest kernel then doesn't get a chance to print
the usual BUG message and stack trace.
Implement handling of the trap exception so that it gets passed to the
guest and the user is left with a more useful log message.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Diffstat (limited to 'arch/mips/kvm/trap_emul.c')
| -rw-r--r-- | arch/mips/kvm/trap_emul.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c index 4372cc86650c..dc019950e243 100644 --- a/arch/mips/kvm/trap_emul.c +++ b/arch/mips/kvm/trap_emul.c @@ -330,6 +330,24 @@ static int kvm_trap_emul_handle_break(struct kvm_vcpu *vcpu) return ret; } +static int kvm_trap_emul_handle_trap(struct kvm_vcpu *vcpu) +{ + struct kvm_run *run = vcpu->run; + uint32_t __user *opc = (uint32_t __user *)vcpu->arch.pc; + unsigned long cause = vcpu->arch.host_cp0_cause; + enum emulation_result er = EMULATE_DONE; + int ret = RESUME_GUEST; + + er = kvm_mips_emulate_trap_exc(cause, opc, run, vcpu); + if (er == EMULATE_DONE) { + ret = RESUME_GUEST; + } else { + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + ret = RESUME_HOST; + } + return ret; +} + static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu) { struct kvm_run *run = vcpu->run; @@ -497,6 +515,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = { .handle_syscall = kvm_trap_emul_handle_syscall, .handle_res_inst = kvm_trap_emul_handle_res_inst, .handle_break = kvm_trap_emul_handle_break, + .handle_trap = kvm_trap_emul_handle_trap, .handle_msa_disabled = kvm_trap_emul_handle_msa_disabled, .vm_init = kvm_trap_emul_vm_init, |