s390x/kvm: Handle bpb feature

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.

Cc: qemu-stable@nongnu.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20180118085628.40798-3-borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[CH: 'Branch Prediction Blocking' -> 'Branch prediction blocking']
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index ae3cee91a239422786f1754ae7d4f09ff820b4d5..d2e6b9f5c703dc187b436ab18205fb48a92ce7f7 100644 (file)
--- 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 915bccbc75918231014093ef22ce702f86853fc4..a1123ad621f42a5b2222af42049c042e891e10bf 100644 (file)
--- 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 31a4676f051093c0dee46ae27bf0d81ad826d76f..b45ef09f93bba2950bdd009a8fd885b136684928 100644 (file)
--- 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 4b6d4e9cc070040c46b154d646440e26cfb0c791..4487cfd53b6bd576722efced61f48c0c69cdb916 100644 (file)
--- 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 b24f6ada5be99bae7f959b189714d4dfe9d7bd1e..563aced35e2490a01c073b7fe4be8396e9f55fbe 100644 (file)
--- 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 6a18a413b49c79434dc89e57370f1dff4b4312cb..87360011560e1d9e855776b303095804e4d947b6 100644 (file)
--- 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)) {
+        cs->kvm_run->s.regs.bpbc = env->bpbc;
+        cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_BPBC;
+    }
+
     /* Finally the prefix */
     if (can_sync_regs(cs, KVM_SYNC_PREFIX)) {
         cs->kvm_run->s.regs.prefix = env->psa;
@@ -600,6 +605,10 @@ int kvm_arch_get_registers(CPUState *cs)
         memcpy(env->gscb, cs->kvm_run->s.regs.gscb, 32);
     }
 
+    if (can_sync_regs(cs, KVM_SYNC_BPBC)) {
+        env->bpbc = cs->kvm_run->s.regs.bpbc;
+    }
+
     /* pfault parameters */
     if (can_sync_regs(cs, KVM_SYNC_PFAULT)) {
         env->pfault_token = cs->kvm_run->s.regs.pft;
@@ -2278,6 +2287,11 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
         clear_bit(S390_FEAT_CMM_NT, model->features);
     }
 
+    /* bpb needs kernel support for migration, VSIE and reset */
+    if (!kvm_check_extension(kvm_state, KVM_CAP_S390_BPB)) {
+        clear_bit(S390_FEAT_BPB, model->features);
+    }
+
     /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
     if (pci_available) {
         set_bit(S390_FEAT_ZPCI, model->features);

diff --git a/target/s390x/machine.c b/target/s390x/machine.c
index b78f326d3a8e60a5267567150874e121c1a506e2..84b49287557136a0184a43a519a79d537e62328c 100644 (file)
--- a/target/s390x/machine.c
+++ b/target/s390x/machine.c
@@ -194,6 +194,22 @@ const VMStateDescription vmstate_gscb = {
         }
 };
 
+static bool bpbc_needed(void *opaque)
+{
+    return s390_has_feat(S390_FEAT_BPB);
+}
+
+const VMStateDescription vmstate_bpbc = {
+    .name = "cpu/bpbc",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = bpbc_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(env.bpbc, S390CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 const VMStateDescription vmstate_s390_cpu = {
     .name = "cpu",
     .post_load = cpu_post_load,
@@ -228,6 +244,7 @@ const VMStateDescription vmstate_s390_cpu = {
         &vmstate_riccb,
         &vmstate_exval,
         &vmstate_gscb,
+        &vmstate_bpbc,
         NULL
     },
 };