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Re: [qemu-s390x] [PATCH v8 3/6] s390x/kvm: enable/disable AP instruction

From: Tony Krowiak
Subject: Re: [qemu-s390x] [PATCH v8 3/6] s390x/kvm: enable/disable AP instruction interpretation for guest
Date: Thu, 13 Sep 2018 09:55:35 -0400
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0

On 09/13/2018 01:28 AM, Thomas Huth wrote:
On 2018-09-12 22:08, Tony Krowiak wrote:
From: Tony Krowiak <address@hidden>

Let's use the KVM_SET_DEVICE_ATTR ioctl to enable or disable
hardware interpretation of AP instructions executed on the guest.
If the S390_FEAT_AP feature is installed, AP instructions will
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 |   16 ++++++++++++++++
  1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index c4bd84d..28a3900 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -2297,6 +2297,19 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
Error **errp)
+static void kvm_s390_configure_apie(int interpret)
In case you respin, maybe use "bool interpret" instead of "int interpret"?


Will do

+    uint64_t attr = KVM_S390_VM_CRYPTO_DISABLE_APIE;
+    if (interpret) {
+        attr = KVM_S390_VM_CRYPTO_ENABLE_APIE;
+    }
+    if (kvm_vm_check_attr(kvm_state, KVM_S390_VM_CRYPTO, attr)) {
+            kvm_s390_set_attr(attr);
+    }
  void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
      struct kvm_s390_vm_cpu_processor prop  = {
@@ -2346,6 +2359,9 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model, 
Error **errp)
      if (test_bit(S390_FEAT_CMM, model->features)) {
+    /* configure hardware interpretation of AP instructions */
+    kvm_s390_configure_apie(test_bit(S390_FEAT_AP, model->features));
void kvm_s390_restart_interrupt(S390CPU *cpu)

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