KVM: PPC: Book3s: Remove kvmppc_read_inst() function

In the context of replacing kvmppc_ld() function calls with a version of
kvmppc_get_last_inst() which allow to fail, Alex Graf suggested this:

"If we get EMULATE_AGAIN, we just have to make sure we go back into the guest.
No need to inject an ISI into  the guest - it'll do that all by itself.
With an error returning kvmppc_get_last_inst we can just use completely
get rid of kvmppc_read_inst() and only use kvmppc_get_last_inst() instead."

As a intermediate step get rid of kvmppc_read_inst() and only use kvmppc_ld()
instead.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 34 insertions, 51 deletions

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index e40765f8cbad..e76aec38ec21 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -710,42 +710,6 @@ static void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac)
 #endif
 }
 
-static int kvmppc_read_inst(struct kvm_vcpu *vcpu)
-{
-        ulong srr0 = kvmppc_get_pc(vcpu);
-        u32 last_inst = kvmppc_get_last_inst(vcpu);
-        int ret;
-
-        ret = kvmppc_ld(vcpu, &srr0, sizeof(u32), &last_inst, false);
-        if (ret == -ENOENT) {
-                ulong msr = kvmppc_get_msr(vcpu);
-
-                msr = kvmppc_set_field(msr, 33, 33, 1);
-                msr = kvmppc_set_field(msr, 34, 36, 0);
-                msr = kvmppc_set_field(msr, 42, 47, 0);
-                kvmppc_set_msr_fast(vcpu, msr);
-                kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_INST_STORAGE);
-                return EMULATE_AGAIN;
-        }
-
-        return EMULATE_DONE;
-}
-
-static int kvmppc_check_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr)
-{
-
-        /* Need to do paired single emulation? */
-        if (!(vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE))
-                return EMULATE_DONE;
-
-        /* Read out the instruction */
-        if (kvmppc_read_inst(vcpu) == EMULATE_DONE)
-                /* Need to emulate */
-                return EMULATE_FAIL;
-
-        return EMULATE_AGAIN;
-}
-
 /* Handle external providers (FPU, Altivec, VSX) */
 static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
                              ulong msr)
@@ -1149,31 +1113,49 @@ program_interrupt:
         case BOOK3S_INTERRUPT_VSX:
         {
                 int ext_msr = 0;
+                int emul;
+                ulong pc;
+                u32 last_inst;
+
+                if (vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE) {
+                        /* Do paired single instruction emulation */
+                        pc = kvmppc_get_pc(vcpu);
+                        last_inst = kvmppc_get_last_inst(vcpu);
+                        emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst,
+                                         false);
+                        if (emul == EMULATE_DONE)
+                                goto program_interrupt;
+                        else
+                                r = RESUME_GUEST;
 
-                switch (exit_nr) {
-                case BOOK3S_INTERRUPT_FP_UNAVAIL: ext_msr = MSR_FP;  break;
-                case BOOK3S_INTERRUPT_ALTIVEC:    ext_msr = MSR_VEC; break;
-                case BOOK3S_INTERRUPT_VSX:        ext_msr = MSR_VSX; break;
+                        break;
                 }
 
-                switch (kvmppc_check_ext(vcpu, exit_nr)) {
-                case EMULATE_DONE:
-                        /* everything ok - let's enable the ext */
-                        r = kvmppc_handle_ext(vcpu, exit_nr, ext_msr);
+                /* Enable external provider */
+                switch (exit_nr) {
+                case BOOK3S_INTERRUPT_FP_UNAVAIL:
+                        ext_msr = MSR_FP;
                         break;
-                case EMULATE_FAIL:
-                        /* we need to emulate this instruction */
-                        goto program_interrupt;
+
+                case BOOK3S_INTERRUPT_ALTIVEC:
+                        ext_msr = MSR_VEC;
                         break;
-                default:
-                        /* nothing to worry about - go again */
+
+                case BOOK3S_INTERRUPT_VSX:
+                        ext_msr = MSR_VSX;
                         break;
                 }
+
+                r = kvmppc_handle_ext(vcpu, exit_nr, ext_msr);
                 break;
         }
         case BOOK3S_INTERRUPT_ALIGNMENT:
-                if (kvmppc_read_inst(vcpu) == EMULATE_DONE) {
-                        u32 last_inst = kvmppc_get_last_inst(vcpu);
+        {
+                ulong pc = kvmppc_get_pc(vcpu);
+                u32 last_inst = kvmppc_get_last_inst(vcpu);
+                int emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst, false);
+
+                if (emul == EMULATE_DONE) {
                         u32 dsisr;
                         u64 dar;
 
@@ -1187,6 +1169,7 @@ program_interrupt:
                 }
                 r = RESUME_GUEST;
                 break;
+        }
 #ifdef CONFIG_PPC_BOOK3S_64
         case BOOK3S_INTERRUPT_FAC_UNAVAIL:
                 kvmppc_handle_fac(vcpu, vcpu->arch.shadow_fscr >> 56);