On 01/18/2018 01:01 PM, Halil Pasic wrote: > > > On 01/18/2018 09:56 AM, Christian Borntraeger wrote: >> We need to handle the bpb control on reset and migration. Normally >> stfle.82 is transparent (and the normal guest part works without >> hypervisor activity). To prevent any issues we require full >> host kernel support for this feature. >> >> Signed-off-by: Christian Borntraeger <[email protected]> >> --- >> target/s390x/cpu.c | 1 + >> target/s390x/cpu.h | 1 + >> target/s390x/cpu_features.c | 1 + >> target/s390x/cpu_features_def.h | 1 + >> target/s390x/gen-features.c | 1 + >> target/s390x/kvm.c | 14 ++++++++++++++ >> target/s390x/machine.c | 17 +++++++++++++++++ >> 7 files changed, 36 insertions(+) >> >> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c >> index ae3cee9..d2e6b9f 100644 >> --- a/target/s390x/cpu.c >> +++ b/target/s390x/cpu.c >> @@ -89,6 +89,7 @@ static void s390_cpu_reset(CPUState *s) >> CPUS390XState *env = &cpu->env; >> >> env->pfault_token = -1UL; >> + env->bpbc = false; >> scc->parent_reset(s); >> cpu->env.sigp_order = 0; >> s390_cpu_set_state(CPU_STATE_STOPPED, cpu); >> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h >> index 1a8b6b9..c0ef85d 100644 >> --- a/target/s390x/cpu.h >> +++ b/target/s390x/cpu.h >> @@ -93,6 +93,7 @@ struct CPUS390XState { >> >> uint32_t fpc; /* floating-point control register */ >> uint32_t cc_op; >> + bool bpbc; /* branch prediction blocking */ >> >> float_status fpu_status; /* passed to softfloat lib */ >> >> diff --git a/target/s390x/cpu_features.c b/target/s390x/cpu_features.c >> index 31a4676..5d1c210 100644 >> --- a/target/s390x/cpu_features.c >> +++ b/target/s390x/cpu_features.c >> @@ -89,6 +89,7 @@ static const S390FeatDef s390_features[] = { >> FEAT_INIT("msa4-base", S390_FEAT_TYPE_STFL, 77, >> "Message-security-assist-extension-4 facility (excluding subfunctions)"), >> FEAT_INIT("edat2", S390_FEAT_TYPE_STFL, 78, "Enhanced-DAT facility 2"), >> FEAT_INIT("dfppc", S390_FEAT_TYPE_STFL, 80, "Decimal-floating-point >> packed-conversion facility"), >> + FEAT_INIT("bpb", S390_FEAT_TYPE_STFL, 82, "Branch Prediction Blocking"), >> FEAT_INIT("vx", S390_FEAT_TYPE_STFL, 129, "Vector facility"), >> FEAT_INIT("iep", S390_FEAT_TYPE_STFL, 130, >> "Instruction-execution-protection facility"), >> FEAT_INIT("sea_esop2", S390_FEAT_TYPE_STFL, 131, "Side-effect-access >> facility and Enhanced-suppression-on-protection facility 2"), >> diff --git a/target/s390x/cpu_features_def.h >> b/target/s390x/cpu_features_def.h >> index 4b6d4e9..4487cfd 100644 >> --- a/target/s390x/cpu_features_def.h >> +++ b/target/s390x/cpu_features_def.h >> @@ -80,6 +80,7 @@ typedef enum { >> S390_FEAT_MSA_EXT_4, >> S390_FEAT_EDAT_2, >> S390_FEAT_DFP_PACKED_CONVERSION, >> + S390_FEAT_BPB, >> S390_FEAT_VECTOR, >> S390_FEAT_INSTRUCTION_EXEC_PROT, >> S390_FEAT_SIDE_EFFECT_ACCESS_ESOP2, >> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c >> index b24f6ad..563aced 100644 >> --- a/target/s390x/gen-features.c >> +++ b/target/s390x/gen-features.c >> @@ -352,6 +352,7 @@ static uint16_t base_GEN14_GA1[] = { >> * support these features yet. >> */ >> static uint16_t full_GEN7_GA1[] = { >> + S390_FEAT_BPB, >> S390_FEAT_SIE_F2, >> S390_FEAT_SIE_SKEY, >> S390_FEAT_SIE_GPERE, >> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c >> index 6a18a41..8736001 100644 >> --- a/target/s390x/kvm.c >> +++ b/target/s390x/kvm.c >> @@ -490,6 +490,11 @@ int kvm_arch_put_registers(CPUState *cs, int level) >> cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_GSCB; >> } >> >> + if (can_sync_regs(cs, KVM_SYNC_BPBC)) { > > This is for compat machines <= 2.7, or? Should the guest of these get the > STFLE bit 82 regardless of the outcome of kvm_check_extension(kvm_state, > KVM_CAP_S390_BPB) > if we have STFLE bit 82 in the host?
I mirror the bpbc in the env of the CPU, mostly to properly reset the bpbc value on reset. We need this here to have the up-to-date values in QEMU (on synchronize-state) and kernel (on synchronize-back). So whenever the kernel exposes this we will reset bpbc on reset.
