On 28.06.14 00:49, Mihai Caraman wrote:
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.cara...@freescale.com>
---
v4:
  - new patch

  arch/powerpc/kvm/book3s_pr.c | 85 ++++++++++++++++++--------------------------
  1 file changed, 35 insertions(+), 50 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 15fd6c2..d247d88 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -665,42 +665,6 @@ 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)
@@ -1101,31 +1065,51 @@ program_interrupt:
        case BOOK3S_INTERRUPT_VSX:
        {
                int ext_msr = 0;
+               int emul;
+               ulong pc;
+               u32 last_inst;
- 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;
-               }
+               if (!(vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE)) {

Please make paired single emulation the unusual, if()'ed case, not the normal exit path :).


Alex
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