KVM: PPC: Emulator: clean up instruction parsing
Instructions on PPC are pretty similarly encoded. So instead of
every instruction emulation code decoding the instruction fields
itself, we can move that code to more generic places and rely on
the compiler to optimize the unused bits away.
This has 2 advantages. It makes the code smaller and it makes the
code less error prone, as the instruction fields are always
available, so accidental misusage is reduced.
Functionally, this patch doesn't change anything.
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 904412b..e14f7b2 100644
--- a/arch/powerpc/kvm/booke_emulate.c
+++ b/arch/powerpc/kvm/booke_emulate.c
@@ -40,8 +40,8 @@
unsigned int inst, int *advance)
{
int emulated = EMULATE_DONE;
- int rs;
- int rt;
+ int rs = get_rs(inst);
+ int rt = get_rt(inst);
switch (get_op(inst)) {
case 19:
@@ -62,19 +62,16 @@
switch (get_xop(inst)) {
case OP_31_XOP_MFMSR:
- rt = get_rt(inst);
kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->msr);
kvmppc_set_exit_type(vcpu, EMULATED_MFMSR_EXITS);
break;
case OP_31_XOP_MTMSR:
- rs = get_rs(inst);
kvmppc_set_exit_type(vcpu, EMULATED_MTMSR_EXITS);
kvmppc_set_msr(vcpu, kvmppc_get_gpr(vcpu, rs));
break;
case OP_31_XOP_WRTEE:
- rs = get_rs(inst);
vcpu->arch.shared->msr = (vcpu->arch.shared->msr & ~MSR_EE)
| (kvmppc_get_gpr(vcpu, rs) & MSR_EE);
kvmppc_set_exit_type(vcpu, EMULATED_WRTEE_EXITS);