> -----Original Message----- > From: kvm-ppc-ow...@vger.kernel.org [mailto:kvm-ppc-ow...@vger.kernel.org] On > Behalf Of > Alexander Graf > Sent: Monday, January 09, 2012 8:15 AM > To: Liu Yu-B13201 > Cc: kvm-...@vger.kernel.org; kvm@vger.kernel.org; ga...@kernel.crashing.org; > Wood Scott- > B07421; Tabi Timur-B04825 > Subject: Re: [PATCH v2 2/3] KVM: PPC: epapr: Add idle hcall support for host > > > On 05.01.2012, at 10:07, Liu Yu wrote: > > > And add a new flag definition in kvm_ppc_pvinfo to indicate whether > > host support EV_IDLE hcall. > > > > Signed-off-by: Liu Yu <yu....@freescale.com> > > --- > > v2: > > 1. instead of adding new field in kvm_ppc_pvinfo, use flags. > > 2. expose hcall definitions to userspace > > > > arch/powerpc/include/asm/kvm_para.h | 14 ++++++++++++-- > > arch/powerpc/kvm/powerpc.c | 8 ++++++++ > > include/linux/kvm.h | 2 ++ > > 3 files changed, 22 insertions(+), 2 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/kvm_para.h > > b/arch/powerpc/include/asm/kvm_para.h > > index 50533f9..e8632b6 100644 > > --- a/arch/powerpc/include/asm/kvm_para.h > > +++ b/arch/powerpc/include/asm/kvm_para.h > > @@ -41,9 +41,19 @@ struct kvm_vcpu_arch_shared { }; > > > > #define KVM_SC_MAGIC_R0 0x4b564d21 /* "KVM!" */ > > -#define HC_VENDOR_KVM (42 << 16) > > + > > +#include <asm/epapr_hcalls.h> > > + > > +/* ePAPR Hypercall Vendor ID */ > > +#define HC_VENDOR_EPAPR (EV_EPAPR_VENDOR_ID << 16) > > +#define HC_VENDOR_KVM (EV_KVM_VENDOR_ID << 16) > > + > > +/* ePAPR Hypercall Token */ > > +#define HC_EV_IDLE EV_IDLE > > + > > +/* ePAPR Hypercall Return Codes */ > > #define HC_EV_SUCCESS 0 > > -#define HC_EV_UNIMPLEMENTED 12 > > +#define HC_EV_UNIMPLEMENTED EV_UNIMPLEMENTED > > > > #define KVM_FEATURE_MAGIC_PAGE 1 > > > > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > > index c33f6a7..1242ee1 100644 > > --- a/arch/powerpc/kvm/powerpc.c > > +++ b/arch/powerpc/kvm/powerpc.c > > @@ -81,6 +81,10 @@ int kvmppc_kvm_pv(struct kvm_vcpu *vcpu) > > > > /* Second return value is in r4 */ > > break; > > + case HC_VENDOR_EPAPR | HC_EV_IDLE: > > + r = HC_EV_SUCCESS; > > + kvm_vcpu_block(vcpu); > > Hrm. This will return on signal. So if the guest sends an idle hcall, then > user space gets a > random signal, we'll continue executing the guest CPU, getting us out of idle > even though the > guest didn't expect it, since the guest really wants to get an interrupt > after the idle hcall.
Is that a problem though? Won't it be just like a spurious interrupt where the guest would wake up, see that there is nothing to do, and then go idle again? What is your concern here? > Maybe we should just set the MSR_WE bit, so we'll get back into wait state on > next vcpu_run? > But then again that's guest visible, so I suppose a separate flag would be > better. Put a separate flag where? Stuart -- 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
