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>
(cherry picked from commit b073c87517d4d348c7bac0f0b35e8e83e6354d82)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.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 4db8b5409ecaf332edc6304e12379dc465721306..23053e3b6a6bb9f44712ef927861531fce907d35 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 68e6c31b4b00d4cc3c4c3d441eed91ee1d8161eb..13a6291a3c5711652a074b27d15413eac5b0ee0a 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 b03f583032ebd8e56615a72fd1fdf28904d8bcdd..2abc4ade6c22ef26556360cd48fc7fec9ec4e53e 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;
@@ -2298,6 +2307,11 @@ 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
     },
 };