From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Tue, 6 Feb 2018 10:19:28 +0000
Subject: KVM: s390: use switch vs jump table in intercept.c
Git-commit: cb7485da3ed1ac4ef6c71d4b2b715f8b87f118c8
Patch-mainline: v4.16-rc4
References: jsc#SLE-6412
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>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
arch/s390/kvm/intercept.c | 51 +++++++++++++++++++++++++++--------------------
arch/s390/kvm/kvm-s390.h | 2 --
2 files changed, 29 insertions(+), 24 deletions(-)
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 9c7d70715862..07c6e81163bf 100644
--- 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 0dc992011f48..79b720887cb0 100644
--- 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