On 15.07.2013, at 13:38, Bhushan Bharat-R65777 wrote: > > >> -----Original Message----- >> From: Alexander Graf [mailto:ag...@suse.de] >> Sent: Monday, July 15, 2013 5:02 PM >> To: Bhushan Bharat-R65777 >> Cc: kvm@vger.kernel.org; kvm-...@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?
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. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
