KVM: s390: Add operation exception interception handler

This commit introduces code that handles operation exception
interceptions. With this handler we can emulate instructions by using
illegal opcodes.

Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 37b9017..093ea14 100644 (file)
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -255,6 +255,7 @@ struct kvm_vcpu_stat {
        u32 instruction_stctg;
        u32 exit_program_interruption;
        u32 exit_instr_and_program;
+       u32 exit_operation_exception;
        u32 deliver_external_call;
        u32 deliver_emergency_signal;
        u32 deliver_service_signal;

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 2e6b54e..09c13db 100644 (file)
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -349,6 +349,15 @@ static int handle_partial_execution(struct kvm_vcpu *vcpu)
        return -EOPNOTSUPP;
 }
 
+static int handle_operexc(struct kvm_vcpu *vcpu)
+{
+       vcpu->stat.exit_operation_exception++;
+       trace_kvm_s390_handle_operexc(vcpu, vcpu->arch.sie_block->ipa,
+                                     vcpu->arch.sie_block->ipb);
+
+       return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
+}
+
 int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
 {
        if (kvm_is_ucontrol(vcpu->kvm))
@@ -370,6 +379,8 @@ int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
                return handle_validity(vcpu);
        case 0x28:
                return handle_stop(vcpu);
+       case 0x2c:
+               return handle_operexc(vcpu);
        case 0x38:
                return handle_partial_execution(vcpu);
        default:

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 6d8ec3a..f0addec 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -63,6 +63,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
        { "exit_instruction", VCPU_STAT(exit_instruction) },
        { "exit_program_interruption", VCPU_STAT(exit_program_interruption) },
        { "exit_instr_and_program_int", VCPU_STAT(exit_instr_and_program) },
+       { "exit_operation_exception", VCPU_STAT(exit_operation_exception) },
        { "halt_successful_poll", VCPU_STAT(halt_successful_poll) },
        { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) },
        { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) },

diff --git a/arch/s390/kvm/trace.h b/arch/s390/kvm/trace.h
index 916834d..90d26a6 100644 (file)
--- a/arch/s390/kvm/trace.h
+++ b/arch/s390/kvm/trace.h
@@ -412,6 +412,27 @@ TRACE_EVENT(kvm_s390_handle_stsi,
                           __entry->addr)
        );
 
+TRACE_EVENT(kvm_s390_handle_operexc,
+           TP_PROTO(VCPU_PROTO_COMMON, __u16 ipa, __u32 ipb),
+           TP_ARGS(VCPU_ARGS_COMMON, ipa, ipb),
+
+           TP_STRUCT__entry(
+                   VCPU_FIELD_COMMON
+                   __field(__u64, instruction)
+                   ),
+
+           TP_fast_assign(
+                   VCPU_ASSIGN_COMMON
+                   __entry->instruction = ((__u64)ipa << 48) |
+                   ((__u64)ipb << 16);
+                   ),
+
+           VCPU_TP_PRINTK("operation exception on instruction %016llx (%s)",
+                          __entry->instruction,
+                          __print_symbolic(icpt_insn_decoder(__entry->instruction),
+                                           icpt_insn_codes))
+       );
+
 #endif /* _TRACE_KVM_H */
 
 /* This part must be outside protection */