On 18/08/2023 13.15, Steffen Eiden wrote:
Enabling AP-passthrough(AP-pt) for PV-guest by using the new CPU
features for PV-AP-pt of KVM.
As usual QEMU first checks which CPU features are available and then
sets them if available and selected by user. An additional check is done
to verify that PV-AP can only be enabled if "regular" AP-pt is enabled
as well. Note that KVM itself does not enforce this restriction.
Signed-off-by: Steffen Eiden <sei...@linux.ibm.com>
---
...
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index a7e2cdf668..937387a768 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -2307,6 +2307,42 @@ static bool ap_enabled(const S390FeatBitmap features)
return test_bit(S390_FEAT_AP, features);
}
+static bool uv_feat_supported(void)
+{
+ return kvm_vm_check_attr(kvm_state, KVM_S390_VM_CPU_MODEL,
+ KVM_S390_VM_CPU_PROCESSOR_UV_FEAT_GUEST);
+}
+
+static int query_uv_feat_guest(S390FeatBitmap features)
+{
+ struct kvm_s390_vm_cpu_uv_feat prop = {};
+ struct kvm_device_attr attr = {
+ .group = KVM_S390_VM_CPU_MODEL,
+ .attr = KVM_S390_VM_CPU_MACHINE_UV_FEAT_GUEST,
+ .addr = (uint64_t) &prop,
+ };
+ int rc;
+
+ // AP support check is currently the only user of the UV feature test.
Cosmetical nit: QEMU coding style mandates /* ... */ comments
+ if (!(uv_feat_supported() && ap_available())) {
+ return 0;
+ }
+
+ rc = kvm_vm_ioctl(kvm_state, KVM_GET_DEVICE_ATTR, &attr);
+ if (rc) {
+ return rc;
+ }
+
+ if (prop.ap) {
+ set_bit(S390_FEAT_UV_FEAT_AP, features);
+ }
+ if (prop.ap_intr) {
+ set_bit(S390_FEAT_UV_FEAT_AP_INTR, features);
+ }
+
+ return 0;
+}
+
static int kvm_to_feat[][2] = {
{ KVM_S390_VM_CPU_FEAT_ESOP, S390_FEAT_ESOP },
{ KVM_S390_VM_CPU_FEAT_SIEF2, S390_FEAT_SIE_F2 },
@@ -2501,11 +2537,39 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model,
Error **errp)
set_bit(S390_FEAT_DIAG_318, model->features);
}
+ /* Test for Ultravisor features that influence secure guest behavior */
+ query_uv_feat_guest(model->features);
+
/* strip of features that are not part of the maximum model */
bitmap_and(model->features, model->features, model->def->full_feat,
S390_FEAT_MAX);
}
+static int configure_uv_feat_guest(const S390FeatBitmap features)
+{
+
Nit: Please remove the empty line.
+ struct kvm_s390_vm_cpu_uv_feat uv_feat = {};
+ struct kvm_device_attr attribute = {
+ .group = KVM_S390_VM_CPU_MODEL,
+ .attr = KVM_S390_VM_CPU_PROCESSOR_UV_FEAT_GUEST,
+ .addr = (__u64) &uv_feat,
+ };
+
+ // AP support check is currently the only user of the UV feature test.
Nit: /* ... */ comment, please
+ if (!(uv_feat_supported() && ap_enabled(features))) {
+ return 0;
+ }
+
+ if (test_bit(S390_FEAT_UV_FEAT_AP, features)) {
+ uv_feat.ap = 1;
+ }
+ if (test_bit(S390_FEAT_UV_FEAT_AP_INTR, features)) {
+ uv_feat.ap_intr = 1;
+ }
+
+ return kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attribute);
+}
+
static void kvm_s390_configure_apie(bool interpret)
{
uint64_t attr = interpret ? KVM_S390_VM_CRYPTO_ENABLE_APIE :
@@ -2569,6 +2633,13 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model,
Error **errp)
if (ap_enabled(model->features)) {
kvm_s390_configure_apie(true);
}
+
+ /* configure UV-features for the guest indicated via query / test_bit */
+ rc = configure_uv_feat_guest(model->features);
+ if (rc) {
+ error_setg(errp, "KVM: Error configuring CPU UV features %d", rc);
+ return;
+ }
}
void kvm_s390_restart_interrupt(S390CPU *cpu)
With the nits fixed:
Reviewed-by: Thomas Huth <th...@redhat.com>
