KVM: s390: use switch vs jump table in intercept.c

Instead of having huge jump tables for function selection,
let's use normal switch/case statements for the instruction
handlers in intercept.c We can now also get rid of
intercept_handler_t.

This allows the compiler to make the right decision depending
on the situation (e.g. avoid jump-tables for thunks).

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 9c7d707158622e7f0743570db60599fa95a9de3b..07c6e81163bf5e248c1b744f69b75548aeae5d44 100644 (file)
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -22,22 +22,6 @@
 #include "trace.h"
 #include "trace-s390.h"
 
-
-static const intercept_handler_t instruction_handlers[256] = {
-       [0x01] = kvm_s390_handle_01,
-       [0x82] = kvm_s390_handle_lpsw,
-       [0x83] = kvm_s390_handle_diag,
-       [0xaa] = kvm_s390_handle_aa,
-       [0xae] = kvm_s390_handle_sigp,
-       [0xb2] = kvm_s390_handle_b2,
-       [0xb6] = kvm_s390_handle_stctl,
-       [0xb7] = kvm_s390_handle_lctl,
-       [0xb9] = kvm_s390_handle_b9,
-       [0xe3] = kvm_s390_handle_e3,
-       [0xe5] = kvm_s390_handle_e5,
-       [0xeb] = kvm_s390_handle_eb,
-};
-
 u8 kvm_s390_get_ilen(struct kvm_vcpu *vcpu)
 {
        struct kvm_s390_sie_block *sie_block = vcpu->arch.sie_block;
@@ -129,16 +113,39 @@ static int handle_validity(struct kvm_vcpu *vcpu)
 
 static int handle_instruction(struct kvm_vcpu *vcpu)
 {
-       intercept_handler_t handler;
-
        vcpu->stat.exit_instruction++;
        trace_kvm_s390_intercept_instruction(vcpu,
                                             vcpu->arch.sie_block->ipa,
                                             vcpu->arch.sie_block->ipb);
-       handler = instruction_handlers[vcpu->arch.sie_block->ipa >> 8];
-       if (handler)
-               return handler(vcpu);
-       return -EOPNOTSUPP;
+
+       switch (vcpu->arch.sie_block->ipa >> 8) {
+       case 0x01:
+               return kvm_s390_handle_01(vcpu);
+       case 0x82:
+               return kvm_s390_handle_lpsw(vcpu);
+       case 0x83:
+               return kvm_s390_handle_diag(vcpu);
+       case 0xaa:
+               return kvm_s390_handle_aa(vcpu);
+       case 0xae:
+               return kvm_s390_handle_sigp(vcpu);
+       case 0xb2:
+               return kvm_s390_handle_b2(vcpu);
+       case 0xb6:
+               return kvm_s390_handle_stctl(vcpu);
+       case 0xb7:
+               return kvm_s390_handle_lctl(vcpu);
+       case 0xb9:
+               return kvm_s390_handle_b9(vcpu);
+       case 0xe3:
+               return kvm_s390_handle_e3(vcpu);
+       case 0xe5:
+               return kvm_s390_handle_e5(vcpu);
+       case 0xeb:
+               return kvm_s390_handle_eb(vcpu);
+       default:
+               return -EOPNOTSUPP;
+       }
 }
 
 static int inject_prog_on_prog_intercept(struct kvm_vcpu *vcpu)

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index bd31b37b0e6f83905e7204b2eb439050aaeb1187..3c0a975c2477ea2a1aa8acd03d363ef766ab3740 100644 (file)
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -19,8 +19,6 @@
 #include <asm/processor.h>
 #include <asm/sclp.h>
 
-typedef int (*intercept_handler_t)(struct kvm_vcpu *vcpu);
-
 /* Transactional Memory Execution related macros */
 #define IS_TE_ENABLED(vcpu)    ((vcpu->arch.sie_block->ecb & ECB_TE))
 #define TDB_FORMAT1            1