Am 03.07.2014 um 18:18 schrieb "mihai.caraman@freescale.com" <mihai.caraman@=
freescale.com>:

quoted

-----Original Message-----
From: Alexander Graf [mailto:agraf@suse.de]
Sent: Thursday, July 03, 2014 4:37 PM
To: Caraman Mihai Claudiu-B02008; kvm-ppc@vger.kernel.org
Cc: kvm@vger.kernel.org; linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 3/5 v4] KVM: PPC: Book3s: Remove kvmppc_read_inst()
function
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On 28.06.14 00:49, Mihai Caraman wrote:
In the context of replacing kvmppc_ld() function calls with a version

of

quoted

kvmppc_get_last_inst() which allow to fail, Alex Graf suggested this:
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"If we get EMULATE_AGAIN, we just have to make sure we go back into the

guest.

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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."

quoted

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

kvmppc_ld()

quoted

instead.
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Signed-off-by: Mihai Caraman <redacted>
---
v4:
 - new patch
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 arch/powerpc/kvm/book3s_pr.c | 85 ++++++++++++++++++-----------------

---------

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 1 file changed, 35 insertions(+), 50 deletions(-)
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diff --git a/arch/powerpc/kvm/book3s_pr.c

b/arch/powerpc/kvm/book3s_pr.c

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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)

quoted

 #endif
 }
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-static int kvmppc_read_inst(struct kvm_vcpu *vcpu)
-{
-    ulong srr0 =3D kvmppc_get_pc(vcpu);
-    u32 last_inst =3D kvmppc_get_last_inst(vcpu);
-    int ret;
-
-    ret =3D kvmppc_ld(vcpu, &srr0, sizeof(u32), &last_inst, false);
-    if (ret =3D=3D -ENOENT) {
-        ulong msr =3D kvmppc_get_msr(vcpu);
-
-        msr =3D kvmppc_set_field(msr, 33, 33, 1);
-        msr =3D kvmppc_set_field(msr, 34, 36, 0);
-        msr =3D kvmppc_set_field(msr, 42, 47, 0);
-        kvmppc_set_msr_fast(vcpu, msr);
-        kvmppc_book3s_queue_irqprio(vcpu,

BOOK3S_INTERRUPT_INST_STORAGE);

quoted

-        return EMULATE_AGAIN;
-    }
-
-    return EMULATE_DONE;
-}
-
-static int kvmppc_check_ext(struct kvm_vcpu *vcpu, unsigned int

exit_nr)

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-{
-
-    /* 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) =3D=3D 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,

quoted

                  ulong msr)

@@ -1101,31 +1065,51 @@ program_interrupt:
     case BOOK3S_INTERRUPT_VSX:
     {
         int ext_msr =3D 0;
+        int emul;
+        ulong pc;
+        u32 last_inst;

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-        switch (exit_nr) {
-        case BOOK3S_INTERRUPT_FP_UNAVAIL: ext_msr =3D MSR_FP;  break;
-        case BOOK3S_INTERRUPT_ALTIVEC: ext_msr =3D MSR_VEC; break;
-        case BOOK3S_INTERRUPT_VSX:        ext_msr =3D MSR_VSX; break;
-        }
+        if (!(vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE)) {

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

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Huh ... do you have more Book3s specific requests, it will be strange if
it will still work after all this blind changes :)

Heh :).

All I'm saying is that rather than

if (no emulation) {
  foo();
  break;
)

ps_emulation();
break;

We should do

if (ps emulation) {
  ps_emulation();
  break;
}

foo();
break;


Alex