On 15.07.2013, at 17:13, Bhushan Bharat-R65777 wrote: > > >> -----Original Message----- >> From: Alexander Graf [mailto:agraf@xxxxxxx] >> Sent: Monday, July 15, 2013 8:27 PM >> To: Bhushan Bharat-R65777 >> Cc: kvm@xxxxxxxxxxxxxxx; kvm-ppc@xxxxxxxxxxxxxxx; Wood Scott-B07421; Yoder >> Stuart-B08248 >> Subject: Re: [PATCH 2/5] booke: exit to guest userspace for unimplemented hcalls >> in kvm >> >> >> On 15.07.2013, at 16:50, Bhushan Bharat-R65777 wrote: >> >>> >>> >>>> -----Original Message----- >>>> From: Alexander Graf [mailto:agraf@xxxxxxx] >>>> Sent: Monday, July 15, 2013 5:16 PM >>>> To: Bhushan Bharat-R65777 >>>> Cc: kvm@xxxxxxxxxxxxxxx; kvm-ppc@xxxxxxxxxxxxxxx; Wood Scott-B07421; >>>> Yoder >>>> Stuart-B08248 >>>> Subject: Re: [PATCH 2/5] booke: exit to guest userspace for >>>> unimplemented hcalls in kvm >>>> >>>> >>>> On 15.07.2013, at 13:38, Bhushan Bharat-R65777 wrote: >>>> >>>>> >>>>> >>>>>> -----Original Message----- >>>>>> From: Alexander Graf [mailto:agraf@xxxxxxx] >>>>>> Sent: Monday, July 15, 2013 5:02 PM >>>>>> To: Bhushan Bharat-R65777 >>>>>> Cc: kvm@xxxxxxxxxxxxxxx; kvm-ppc@xxxxxxxxxxxxxxx; 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.bhushan@xxxxxxxxxxxxx> >>>>>>> --- >>>>>>> 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? >>>> >>>> User space needs to call enable_cap on this cap, yes. Otherwise a >>>> guest can confuse user space with an hcall exit it can't handle. >>> >>> We do not have enable_cap for book3s, any specific reason why ? >> >> We do. If you enable PAPR, you get PAPR hcalls. If you enable OSI, you get OSI >> hcalls. > > Oh, We check this on book3s_PR and book3s_HV. > >> KVM hcalls on book3s don't return to user space. > > It exits, is not it? "arch/powerpc/kvm/book3s_pr.c" exits with KVM_EXIT_PAPR_HCALL. And same in book3s_pv. It doesn't even start handling the hcall if papr_enabled isn't set ;). Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
