On Fri, May 03, 2019 at 03:53:16PM +1000, Suraj Jitindar Singh wrote: > It is now possible to use nested kvm-hv under tcg, thus allow for it to > be enabled. > > Note that nested kvm-hv requires that rc updates to ptes be done by > software, otherwise the page tables get out of sync. So disable hardware > rc updates when nested kvm-hv is enabled. > > Signed-off-by: Suraj Jitindar Singh <[email protected]> > --- > hw/ppc/spapr_caps.c | 22 ++++++++++++++++++---- > target/ppc/cpu.h | 1 + > target/ppc/mmu-radix64.c | 4 ++-- > 3 files changed, 21 insertions(+), 6 deletions(-) > > diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c > index 3278c09b0f..7fe07d83dd 100644 > --- a/hw/ppc/spapr_caps.c > +++ b/hw/ppc/spapr_caps.c > @@ -389,10 +389,7 @@ static void cap_nested_kvm_hv_apply(SpaprMachineState > *spapr, > return; > } > > - if (tcg_enabled()) { > - error_setg(errp, > - "No Nested KVM-HV support in tcg, try cap-nested-hv=off"); > - } else if (kvm_enabled()) { > + if (kvm_enabled()) { > if (!kvmppc_has_cap_nested_kvm_hv()) { > error_setg(errp, > "KVM implementation does not support Nested KVM-HV, try cap-nested-hv=off"); > @@ -400,6 +397,22 @@ static void cap_nested_kvm_hv_apply(SpaprMachineState > *spapr, > error_setg(errp, > "Error enabling cap-nested-hv with KVM, try cap-nested-hv=off"); > } > + } /* else { nothing required for tcg } */ > +} > + > +static void cap_nested_kvm_hv_cpu_apply(SpaprMachineState *spapr, > + PowerPCCPU *cpu, > + uint8_t val, Error **errp) > +{ > + CPUPPCState *env = &cpu->env; > + > + if (tcg_enabled() && val) { > + if (env->spr[SPR_PVR] != 0x004E1202) {
Hrm. Something other than an explicit PVR check would be nice (or
we'll have to keep hacking this when DD2.3 arrives).
> + error_setg(errp, "Nested KVM-HV only supported on POWER9 DD2.2, "
> + "try cap-nested-hv=off or -cpu power9_v2.2");
> + return;
> + }
> + env->disable_hw_rc_updates = true;
> }
> }
>
> @@ -544,6 +557,7 @@ SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
> .set = spapr_cap_set_bool,
> .type = "bool",
> .apply = cap_nested_kvm_hv_apply,
> + .cpu_apply = cap_nested_kvm_hv_cpu_apply,
> },
> [SPAPR_CAP_LARGE_DECREMENTER] = {
> .name = "large-decr",
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index 426015c9cd..6502e0de82 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -1237,6 +1237,7 @@ struct CPUPPCState {
> target_ulong hv_ptr, regs_ptr;
> struct hv_guest_state l2_hv, l1_saved_hv;
> struct pt_regs l2_regs, l1_saved_regs;
> + bool disable_hw_rc_updates;
> };
>
> #define SET_FIT_PERIOD(a_, b_, c_, d_) \
> diff --git a/target/ppc/mmu-radix64.c b/target/ppc/mmu-radix64.c
> index 2a8147fc38..cc06967dbe 100644
> --- a/target/ppc/mmu-radix64.c
> +++ b/target/ppc/mmu-radix64.c
> @@ -31,9 +31,9 @@
> static inline bool ppc_radix64_hw_rc_updates(CPUPPCState *env)
> {
> #ifdef CONFIG_ATOMIC64
> - return true;
> + return !env->disable_hw_rc_updates;
> #else
> - return !qemu_tcg_mttcg_enabled();
> + return !qemu_tcg_mttcg_enabled() && !env->disable_hw_rc_updates;
> #endif
> }
>
--
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
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