On Fri, Jan 15, 2021 at 02:01:28PM +0530, Bharata B Rao wrote: > On Wed, Jan 13, 2021 at 05:22:56PM +0100, Greg Kurz wrote: > > Hi Bharata, > > > > On Wed, 6 Jan 2021 14:29:10 +0530 > > Bharata B Rao wrote: > > > > > If KVM_CAP_RPT_INVALIDATE KVM capability is enabled, then > > > > > > - indicate the availability of H_RPT_INVALIDATE hcall to the guest via > > > ibm,hypertas-functions property. > > > - Enable the hcall > > > > > > Both the above are done only if the new sPAPR machine capability > > > cap-rpt-invalidate is set. > > > > > > Note: The KVM implementation of the hcall has been posted for upstream > > > review here: > > > https://lore.kernel.org/linuxppc-dev/20210105090557.2150104-1-bharata@linux.ibm.com/T/#t > > > > > > Update to linux-headers/linux/kvm.h here is temporary, will be > > > done via header updates once the kernel change is accepted upstream. > > > > > > Signed-off-by: Bharata B Rao > > > --- > > > > Patch looks mostly fine. A few remarks below. > > > > > hw/ppc/spapr.c | 7 ++++++ > > > hw/ppc/spapr_caps.c | 49 +++++++++++++++++++++++++++++++++++++++ > > > include/hw/ppc/spapr.h | 8 +++++-- > > > linux-headers/linux/kvm.h | 1 + > > > target/ppc/kvm.c | 12 ++++++++++ > > > target/ppc/kvm_ppc.h | 11 +++++++++ > > > 6 files changed, 86 insertions(+), 2 deletions(-) > > > > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > > > index 489cefcb81..0228083800 100644 > > > --- a/hw/ppc/spapr.c > > > +++ b/hw/ppc/spapr.c > > > @@ -890,6 +890,11 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt) > > > add_str(hypertas, "hcall-copy"); > > > add_str(hypertas, "hcall-debug"); > > > add_str(hypertas, "hcall-vphn"); > > > + if (kvm_enabled() && > > > > You shouldn't check KVM here. The capability is enough to decide if we > > should expose "hcall-rpt-invalidate" or not. FWIW we won't even reach > > this code when running with anything but KVM. > > Correct, the capability itself can be only for KVM case. Hrm.. that's kind of a problem in itself. Enabling KVM should not change the guest visible environment. > > > > > > + (spapr_get_cap(spapr, SPAPR_CAP_RPT_INVALIDATE) == SPAPR_CAP_ON)) { > > > + add_str(hypertas, "hcall-rpt-invalidate"); > > > + } > > > + > > > add_str(qemu_hypertas, "hcall-memop1"); > > > > > > if (!kvm_enabled() || kvmppc_spapr_use_multitce()) { > > > @@ -2021,6 +2026,7 @@ static const VMStateDescription vmstate_spapr = { > > > &vmstate_spapr_cap_ccf_assist, > > > &vmstate_spapr_cap_fwnmi, > > > &vmstate_spapr_fwnmi, > > > + &vmstate_spapr_cap_rpt_invalidate, > > > NULL > > > } > > > }; > > > @@ -4478,6 +4484,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data) > > > smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON; > > > smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_ON; > > > smc->default_caps.caps[SPAPR_CAP_FWNMI] = SPAPR_CAP_ON; > > > + smc->default_caps.caps[SPAPR_CAP_RPT_INVALIDATE] = SPAPR_CAP_OFF; > > > > Any reason for not enabling this for the default machine type and > > disabling it for existing machine types only ? > > If this capability is enabled, then > > 1. First level guest (L1) can off-load the TLB invalidations to the > new hcall if the platform has disabled LPCR[GTSE]. > > 2. Nested guest (L2) will switch to this new hcall rather than using > the old H_TLB_INVALIDATE hcall. > > Case 2 is optional and case 1 makes sense only if LPCR[GTSE]=off. > Hence I thought keeping it off by default and expecting the > user to turn it on only if required would be correct. > > Please note that turning this capability ON will result in the > new hcall being exposed to the guest. I hope this is the right > usage of spapr-caps? > > > > diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h > > > index 73ce2bc951..8e27f8421f 100644 > > > --- a/target/ppc/kvm_ppc.h > > > +++ b/target/ppc/kvm_ppc.h > > > @@ -24,6 +24,7 @@ void kvmppc_enable_logical_ci_hcalls(void); > > > void kvmppc_enable_set_mode_hcall(void); > > > void kvmppc_enable_clear_ref_mod_hcalls(void); > > > void kvmppc_enable_h_page_init(void); > > > +void kvmppc_enable_h_rpt_invalidate(void); > > > void kvmppc_set_papr(PowerPCCPU *cpu); > > > int kvmppc_set_compat(PowerPCCPU *cpu, uint32_t compat_pvr); > > > void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int mpic_proxy); > > > @@ -72,6 +73,7 @@ bool kvmppc_has_cap_nested_kvm_hv(void); > > > int kvmppc_set_cap_nested_kvm_hv(int enable); > > > int kvmppc_get_cap_large_decr(void); > > > int kvmppc_enable_cap_large_decr(PowerPCCPU *cpu, int enable); > > > +int kvmppc_has_cap_rpt_invalidate(void); > > > int kvmppc_enable_hwrng(void); > > > int kvmppc_put_books_sregs(PowerPCCPU *cpu); > > > PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void); > > > @@ -151,6 +153,10 @@ static inline void kvmppc_enable_h_page_init(void) > > > { > > > } > > > > > > +static inline void kvmppc_enable_h_rpt_invalidate(void) > > > +{ > > > > g_assert_not_reached() ? > > Don't see many others doing that, is that a new preferred > way? Pretty much, yes. > > Regards, > Bharata. > -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson