diff options
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/ppc/spapr.c | 5 | ||||
| -rw-r--r-- | hw/ppc/spapr_caps.c | 21 |
2 files changed, 21 insertions, 5 deletions
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index a0076e5fbd..fe8266a1d1 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -4397,7 +4397,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data) smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = 16; /* 64kiB */ smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF; smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON; - smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF; + smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_ON; spapr_caps_add_properties(smc, &error_abort); smc->irq = &spapr_irq_dual; smc->dr_phb_enabled = true; @@ -4465,8 +4465,11 @@ DEFINE_SPAPR_MACHINE(5_0, "5.0", true); */ static void spapr_machine_4_2_class_options(MachineClass *mc) { + SpaprMachineClass *smc = SPAPR_MACHINE_CLASS(mc); + spapr_machine_5_0_class_options(mc); compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len); + smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF; } DEFINE_SPAPR_MACHINE(4_2, "4.2", false); diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c index 481dfd2a27..7f933a98ed 100644 --- a/hw/ppc/spapr_caps.c +++ b/hw/ppc/spapr_caps.c @@ -485,11 +485,24 @@ static void cap_ccf_assist_apply(SpaprMachineState *spapr, uint8_t val, uint8_t kvm_val = kvmppc_get_cap_count_cache_flush_assist(); if (tcg_enabled() && val) { - /* TODO - for now only allow broken for TCG */ - error_setg(errp, -"Requested count cache flush assist capability level not supported by tcg," - " try appending -machine cap-ccf-assist=off"); + /* TCG doesn't implement anything here, but allow with a warning */ + warn_report("TCG doesn't support requested feature, cap-ccf-assist=on"); } else if (kvm_enabled() && (val > kvm_val)) { + uint8_t kvm_ibs = kvmppc_get_cap_safe_indirect_branch(); + + if (kvm_ibs == SPAPR_CAP_FIXED_CCD) { + /* + * If we don't have CCF assist on the host, the assist + * instruction is a harmless no-op. It won't correctly + * implement the cache count flush *but* if we have + * count-cache-disabled in the host, that flush is + * unnnecessary. So, specifically allow this case. This + * allows us to have better performance on POWER9 DD2.3, + * while still working on POWER9 DD2.2 and POWER8 host + * cpus. + */ + return; + } error_setg(errp, "Requested count cache flush assist capability level not supported by kvm," " try appending -machine cap-ccf-assist=off"); |