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target/s390x: AP-passthrough for PV guests

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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.

Reviewed-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Message-ID: <20230823142219.1046522-6-seiden@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Steffen Eiden 2023-08-23 16:22:19 +02:00 • committed by Thomas Huth
parent 354383c122
commit 5ac951519c
5 changed files with 79 additions and 0 deletions
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70
target/s390x/kvm/kvm.c
View file

@ -2299,6 +2299,42 @@ 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 */
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 },
@ -2493,11 +2529,38 @@ 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)
{
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 */
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 :
@ -2561,6 +2624,13 @@ 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)