KVM: PPC: Book3S PR: Refactor program interrupt related code into separate function

The function kvmppc_handle_exit_pr() is quite huge and thus hard to read,
and even contains a "spaghetti-code"-like goto between the different case
labels of the big switch statement. This can be made much more readable
by moving the code related to injecting program interrupts / instruction
emulation into a separate function instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 1482961..d4dfc0c 100644 (file)
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -902,6 +902,69 @@ static void kvmppc_clear_debug(struct kvm_vcpu *vcpu)
        }
 }
 
+static int kvmppc_exit_pr_progint(struct kvm_run *run, struct kvm_vcpu *vcpu,
+                                 unsigned int exit_nr)
+{
+       enum emulation_result er;
+       ulong flags;
+       u32 last_inst;
+       int emul, r;
+
+       /*
+        * shadow_srr1 only contains valid flags if we came here via a program
+        * exception. The other exceptions (emulation assist, FP unavailable,
+        * etc.) do not provide flags in SRR1, so use an illegal-instruction
+        * exception when injecting a program interrupt into the guest.
+        */
+       if (exit_nr == BOOK3S_INTERRUPT_PROGRAM)
+               flags = vcpu->arch.shadow_srr1 & 0x1f0000ull;
+       else
+               flags = SRR1_PROGILL;
+
+       emul = kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst);
+       if (emul != EMULATE_DONE)
+               return RESUME_GUEST;
+
+       if (kvmppc_get_msr(vcpu) & MSR_PR) {
+#ifdef EXIT_DEBUG
+               pr_info("Userspace triggered 0x700 exception at\n 0x%lx (0x%x)\n",
+                       kvmppc_get_pc(vcpu), last_inst);
+#endif
+               if ((last_inst & 0xff0007ff) != (INS_DCBZ & 0xfffffff7)) {
+                       kvmppc_core_queue_program(vcpu, flags);
+                       return RESUME_GUEST;
+               }
+       }
+
+       vcpu->stat.emulated_inst_exits++;
+       er = kvmppc_emulate_instruction(run, vcpu);
+       switch (er) {
+       case EMULATE_DONE:
+               r = RESUME_GUEST_NV;
+               break;
+       case EMULATE_AGAIN:
+               r = RESUME_GUEST;
+               break;
+       case EMULATE_FAIL:
+               pr_crit("%s: emulation at %lx failed (%08x)\n",
+                       __func__, kvmppc_get_pc(vcpu), last_inst);
+               kvmppc_core_queue_program(vcpu, flags);
+               r = RESUME_GUEST;
+               break;
+       case EMULATE_DO_MMIO:
+               run->exit_reason = KVM_EXIT_MMIO;
+               r = RESUME_HOST_NV;
+               break;
+       case EMULATE_EXIT_USER:
+               r = RESUME_HOST_NV;
+               break;
+       default:
+               BUG();
+       }
+
+       return r;
+}
+
 int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu,
                          unsigned int exit_nr)
 {
@@ -1044,71 +1107,8 @@ int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu,
                break;
        case BOOK3S_INTERRUPT_PROGRAM:
        case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
-       {
-               enum emulation_result er;
-               ulong flags;
-               u32 last_inst;
-               int emul;
-
-program_interrupt:
-               /*
-                * shadow_srr1 only contains valid flags if we came here via
-                * a program exception. The other exceptions (emulation assist,
-                * FP unavailable, etc.) do not provide flags in SRR1, so use
-                * an illegal-instruction exception when injecting a program
-                * interrupt into the guest.
-                */
-               if (exit_nr == BOOK3S_INTERRUPT_PROGRAM)
-                       flags = vcpu->arch.shadow_srr1 & 0x1f0000ull;
-               else
-                       flags = SRR1_PROGILL;
-
-               emul = kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst);
-               if (emul != EMULATE_DONE) {
-                       r = RESUME_GUEST;
-                       break;
-               }
-
-               if (kvmppc_get_msr(vcpu) & MSR_PR) {
-#ifdef EXIT_DEBUG
-                       pr_info("Userspace triggered 0x700 exception at\n 0x%lx (0x%x)\n",
-                               kvmppc_get_pc(vcpu), last_inst);
-#endif
-                       if ((last_inst & 0xff0007ff) !=
-                           (INS_DCBZ & 0xfffffff7)) {
-                               kvmppc_core_queue_program(vcpu, flags);
-                               r = RESUME_GUEST;
-                               break;
-                       }
-               }
-
-               vcpu->stat.emulated_inst_exits++;
-               er = kvmppc_emulate_instruction(run, vcpu);
-               switch (er) {
-               case EMULATE_DONE:
-                       r = RESUME_GUEST_NV;
-                       break;
-               case EMULATE_AGAIN:
-                       r = RESUME_GUEST;
-                       break;
-               case EMULATE_FAIL:
-                       printk(KERN_CRIT "%s: emulation at %lx failed (%08x)\n",
-                              __func__, kvmppc_get_pc(vcpu), last_inst);
-                       kvmppc_core_queue_program(vcpu, flags);
-                       r = RESUME_GUEST;
-                       break;
-               case EMULATE_DO_MMIO:
-                       run->exit_reason = KVM_EXIT_MMIO;
-                       r = RESUME_HOST_NV;
-                       break;
-               case EMULATE_EXIT_USER:
-                       r = RESUME_HOST_NV;
-                       break;
-               default:
-                       BUG();
-               }
+               r = kvmppc_exit_pr_progint(run, vcpu, exit_nr);
                break;
-       }
        case BOOK3S_INTERRUPT_SYSCALL:
        {
                u32 last_sc;
@@ -1185,7 +1185,7 @@ program_interrupt:
                        emul = kvmppc_get_last_inst(vcpu, INST_GENERIC,
                                                    &last_inst);
                        if (emul == EMULATE_DONE)
-                               goto program_interrupt;
+                               r = kvmppc_exit_pr_progint(run, vcpu, exit_nr);
                        else
                                r = RESUME_GUEST;