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Re: [qemu-s390x] [PATCH v9 3/6] s390x/kvm: enable AP instruction interpr

From: Pierre Morel
Subject: Re: [qemu-s390x] [PATCH v9 3/6] s390x/kvm: enable AP instruction interpretation for guest
Date: Tue, 2 Oct 2018 17:36:22 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1

On 27/09/2018 09:52, David Hildenbrand wrote:
On 27/09/2018 00:54, Tony Krowiak wrote:
From: Tony Krowiak <address@hidden>

Let's use the KVM_SET_DEVICE_ATTR ioctl to enable hardware
interpretation of AP instructions executed on the guest.
If the S390_FEAT_AP feature is switched on for the guest,
AP instructions must be interpreted by default; otherwise,
they will be intercepted.

This attribute setting may be overridden by a device. For example,
a device may want to provide AP instructions to the guest (i.e.,
S390_FEAT_AP turned on), but it may want to emulate them. In this
case, the AP instructions executed on the guest must be
intercepted; so when the device is realized, it must disable

Signed-off-by: Tony Krowiak <address@hidden>
  target/s390x/kvm.c | 14 ++++++++++++++
  1 file changed, 14 insertions(+)

diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 5277acd79a2c..d55d24abfd78 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -2301,6 +2301,16 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
Error **errp)
+static void kvm_s390_configure_apie(bool interpret)
+    uint64_t attr = interpret ? KVM_S390_VM_CRYPTO_ENABLE_APIE :
+                                KVM_S390_VM_CRYPTO_DISABLE_APIE;
+    if (kvm_vm_check_attr(kvm_state, KVM_S390_VM_CRYPTO, attr)) {
+            kvm_s390_set_attr(attr);

Wrong indentation, apart from that

Reviewed-by: David Hildenbrand <address@hidden>

+    }
  void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
      struct kvm_s390_vm_cpu_processor prop  = {
@@ -2350,6 +2360,10 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model, 
Error **errp)
      if (test_bit(S390_FEAT_CMM, model->features)) {
+    if (test_bit(S390_FEAT_AP, model->features)) {
+        kvm_s390_configure_apie(true);
+    }
void kvm_s390_restart_interrupt(S390CPU *cpu)

Tested-by: Pierre Morel<address@hidden>

Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany

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