[qemu-xen master] s390x/kvm: Handle bpb feature

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[qemu-xen master] s390x/kvm: Handle bpb feature

patchbot
commit 4d79c0e434110219c4de108bda9af13d927f2956
Author:     Christian Borntraeger <[hidden email]>
AuthorDate: Thu Jan 18 09:56:27 2018 +0100
Commit:     Michael Roth <[hidden email]>
CommitDate: Mon Jan 29 08:32:50 2018 -0600

    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: [hidden email]
    Signed-off-by: Christian Borntraeger <[hidden email]>
    Message-Id: <[hidden email]>
    Reviewed-by: Thomas Huth <[hidden email]>
    Reviewed-by: David Hildenbrand <[hidden email]>
    [CH: 'Branch Prediction Blocking' -> 'Branch prediction blocking']
    Signed-off-by: Cornelia Huck <[hidden email]>
   
    (cherry picked from commit b073c87517d4d348c7bac0f0b35e8e83e6354d82)
    Signed-off-by: Michael Roth <[hidden email]>
---
 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 4db8b54..23053e3 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..b45ef09 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 68e6c31..13a6291 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 b03f583..2abc4ad 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)) {
+        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 b78f326..84b4928 100644
--- 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
     },
 };
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#master

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