> -----Original Message-----
> From: Alexander Graf [mailto:ag...@suse.de]
> Sent: Monday, July 15, 2013 5:02 PM
> To: Bhushan Bharat-R65777
> Cc: k...@vger.kernel.org; kvm-ppc@vger.kernel.org; Wood Scott-B07421; Yoder
> Stuart-B08248; Bhushan Bharat-R65777
> Subject: Re: [PATCH 2/5] booke: exit to guest userspace for unimplemented 
> hcalls
> in kvm
> 
> 
> On 15.07.2013, at 13:11, Bharat Bhushan wrote:
> 
> > Exit to guest user space if kvm does not implement the hcall.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com>
> > ---
> > arch/powerpc/kvm/booke.c   |   47 
> > +++++++++++++++++++++++++++++++++++++------
> > arch/powerpc/kvm/powerpc.c |    1 +
> > include/uapi/linux/kvm.h   |    1 +
> > 3 files changed, 42 insertions(+), 7 deletions(-)
> >
> > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index
> > 17722d8..c8b41b4 100644
> > --- a/arch/powerpc/kvm/booke.c
> > +++ b/arch/powerpc/kvm/booke.c
> > @@ -1005,9 +1005,25 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
> kvm_vcpu *vcpu,
> >             break;
> >
> > #ifdef CONFIG_KVM_BOOKE_HV
> > -   case BOOKE_INTERRUPT_HV_SYSCALL:
> > +   case BOOKE_INTERRUPT_HV_SYSCALL: {
> 
> This is getting large. Please extract hcall handling into its own function.
> Maybe you can merge the HV and non-HV case then too.
> 
> > +           int i;
> >             if (!(vcpu->arch.shared->msr & MSR_PR)) {
> > -                   kvmppc_set_gpr(vcpu, 3, kvmppc_kvm_pv(vcpu));
> > +                   r = kvmppc_kvm_pv(vcpu);
> > +                   if (r != EV_UNIMPLEMENTED) {
> > +                           /* except unimplemented return to guest */
> > +                           kvmppc_set_gpr(vcpu, 3, r);
> > +                           kvmppc_account_exit(vcpu, SYSCALL_EXITS);
> > +                           r = RESUME_GUEST;
> > +                           break;
> > +                   }
> > +                   /* Exit to userspace for unimplemented hcalls in kvm */
> > +                   run->epapr_hcall.nr = kvmppc_get_gpr(vcpu, 11);
> > +                   run->epapr_hcall.ret = 0;
> > +                   for (i = 0; i < 8; i++)
> > +                           run->epapr_hcall.args[i] = kvmppc_get_gpr(vcpu, 
> > 3 +
> i);
> > +                   vcpu->arch.hcall_needed = 1;
> > +                   kvmppc_account_exit(vcpu, SYSCALL_EXITS);
> > +                   r = RESUME_HOST;
> >             } else {
> >                     /*
> >                      * hcall from guest userspace -- send privileged @@ 
> > -1016,22
> > +1032,39 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu 
> > *vcpu,
> >                     kvmppc_core_queue_program(vcpu, ESR_PPR);
> >             }
> >
> > -           r = RESUME_GUEST;
> > +           run->exit_reason = KVM_EXIT_EPAPR_HCALL;


Oops, what I have done, I wanted this to be kvmppc_account_exit(vcpu, 
SYSCALL_EXITS);

s/ run->exit_reason = KVM_EXIT_EPAPR_HCALL;/ kvmppc_account_exit(vcpu, 
SYSCALL_EXITS);

-Bharat

> 
> This looks odd. Your exit reason only changes when you do the hcall exiting,
> right?
> 
> You also need to guard user space hcall exits with an ENABLE_CAP. Otherwise
> older user space will break, as it doesn't know about the exit type yet.

So the user space so make enable_cap also?

-Bharat

> 
> 
> Alex
> 
> >             break;
> > +   }
> > #else
> > -   case BOOKE_INTERRUPT_SYSCALL:
> > +   case BOOKE_INTERRUPT_SYSCALL: {
> > +           int i;
> > +           r = RESUME_GUEST;
> >             if (!(vcpu->arch.shared->msr & MSR_PR) &&
> >                 (((u32)kvmppc_get_gpr(vcpu, 0)) == KVM_SC_MAGIC_R0)) {
> >                     /* KVM PV hypercalls */
> > -                   kvmppc_set_gpr(vcpu, 3, kvmppc_kvm_pv(vcpu));
> > -                   r = RESUME_GUEST;
> > +                   r = kvmppc_kvm_pv(vcpu);
> > +                   if (r != EV_UNIMPLEMENTED) {
> > +                           /* except unimplemented return to guest */
> > +                           kvmppc_set_gpr(vcpu, 3, r);
> > +                           kvmppc_account_exit(vcpu, SYSCALL_EXITS);
> > +                           r = RESUME_GUEST;
> > +                           break;
> > +                   }
> > +                   /* Exit to userspace for unimplemented hcalls in kvm */
> > +                   run->epapr_hcall.nr = kvmppc_get_gpr(vcpu, 11);
> > +                   run->epapr_hcall.ret = 0;
> > +                   for (i = 0; i < 8; i++)
> > +                           run->epapr_hcall.args[i] = kvmppc_get_gpr(vcpu, 
> > 3 +
> i);
> > +                   vcpu->arch.hcall_needed = 1;
> > +                   run->exit_reason = KVM_EXIT_EPAPR_HCALL;
> > +                   r = RESUME_HOST;
> >             } else {
> >                     /* Guest syscalls */
> >                     kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_SYSCALL);
> >             }
> >             kvmppc_account_exit(vcpu, SYSCALL_EXITS);
> > -           r = RESUME_GUEST;
> >             break;
> > +   }
> > #endif
> >
> >     case BOOKE_INTERRUPT_DTLB_MISS: {
> > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> > index 4e05f8c..6c6199d 100644
> > --- a/arch/powerpc/kvm/powerpc.c
> > +++ b/arch/powerpc/kvm/powerpc.c
> > @@ -307,6 +307,7 @@ int kvm_dev_ioctl_check_extension(long ext)
> >     case KVM_CAP_PPC_BOOKE_SREGS:
> >     case KVM_CAP_PPC_BOOKE_WATCHDOG:
> >     case KVM_CAP_PPC_EPR:
> > +   case KVM_CAP_EXIT_EPAPR_HCALL:
> > #else
> >     case KVM_CAP_PPC_SEGSTATE:
> >     case KVM_CAP_PPC_HIOR:
> > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index
> > 01ee50e..b5266e5 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -674,6 +674,7 @@ struct kvm_ppc_smmu_info { #define
> > KVM_CAP_PPC_RTAS 91 #define KVM_CAP_IRQ_XICS 92 #define
> > KVM_CAP_ARM_EL1_32BIT 93
> > +#define KVM_CAP_EXIT_EPAPR_HCALL 94
> >
> > #ifdef KVM_CAP_IRQ_ROUTING
> >
> > --
> > 1.7.0.4
> >
> >
> > --
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> > at  http://vger.kernel.org/majordomo-info.html
> 


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