qemu-kvm/kvm-target-s390x-AP-passthrough-for-PV-guests.patch

From 885d04faf5edb787341aab6917fd2de743e029ac Mon Sep 17 00:00:00 2001
From: Steffen Eiden <seiden@linux.ibm.com>
Date: Wed, 23 Aug 2023 16:22:19 +0200
Subject: [PATCH 5/5] target/s390x: AP-passthrough for PV guests
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RH-Author: Thomas Huth <thuth@redhat.com>
RH-MergeRequest: 321: Enable Secure Execution Crypto Passthrough for KVM on s390x
RH-Bugzilla: 2111390
RH-Acked-by: Cédric Le Goater <clg@redhat.com>
RH-Commit: [5/5] 9bf3dfd78fb030a22db7bb756a2cb7f54a0a8d82

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>
(cherry picked from commit 5ac951519c23d9eaf7dc9e2dcbcbc7d9a745ffe7)

Conflicts:
	target/s390x/gen-features.c
	(simple contextual conflict due to missing S390_FEAT_PAIE)
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 target/s390x/cpu_features.h         |  1 +
 target/s390x/cpu_features_def.h.inc |  4 ++
 target/s390x/cpu_models.c           |  2 +
 target/s390x/gen-features.c         |  2 +
 target/s390x/kvm/kvm.c              | 70 +++++++++++++++++++++++++++++
 5 files changed, 79 insertions(+)

diff --git a/target/s390x/cpu_features.h b/target/s390x/cpu_features.h
index 87463f064d..a9bd68a2e1 100644
--- a/target/s390x/cpu_features.h
+++ b/target/s390x/cpu_features.h
@@ -43,6 +43,7 @@ typedef enum {
     S390_FEAT_TYPE_KDSA,
     S390_FEAT_TYPE_SORTL,
     S390_FEAT_TYPE_DFLTCC,
+    S390_FEAT_TYPE_UV_FEAT_GUEST,
 } S390FeatType;
 
 /* Definition of a CPU feature */
diff --git a/target/s390x/cpu_features_def.h.inc b/target/s390x/cpu_features_def.h.inc
index e86662bb3b..aa1f51f2a8 100644
--- a/target/s390x/cpu_features_def.h.inc
+++ b/target/s390x/cpu_features_def.h.inc
@@ -378,3 +378,7 @@ DEF_FEAT(DEFLATE_GHDT, "dfltcc-gdht", DFLTCC, 1, "DFLTCC GDHT")
 DEF_FEAT(DEFLATE_CMPR, "dfltcc-cmpr", DFLTCC, 2, "DFLTCC CMPR")
 DEF_FEAT(DEFLATE_XPND, "dfltcc-xpnd", DFLTCC, 4, "DFLTCC XPND")
 DEF_FEAT(DEFLATE_F0, "dfltcc-f0", DFLTCC, 192, "DFLTCC format 0 parameter-block")
+
+/* Features exposed via the UV-CALL instruction */
+DEF_FEAT(UV_FEAT_AP, "appv", UV_FEAT_GUEST, 4, "AP instructions installed for secure guests")
+DEF_FEAT(UV_FEAT_AP_INTR, "appvi", UV_FEAT_GUEST, 5, "AP instructions interruption support for secure guests")
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 11e06cc51f..454485e706 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -467,6 +467,8 @@ static void check_consistency(const S390CPUModel *model)
         { S390_FEAT_DIAG_318, S390_FEAT_EXTENDED_LENGTH_SCCB },
         { S390_FEAT_NNPA, S390_FEAT_VECTOR },
         { S390_FEAT_RDP, S390_FEAT_LOCAL_TLB_CLEARING },
+        { S390_FEAT_UV_FEAT_AP, S390_FEAT_AP },
+        { S390_FEAT_UV_FEAT_AP_INTR, S390_FEAT_UV_FEAT_AP },
     };
     int i;
 
diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
index 7cb1a6ec10..b789288c82 100644
--- a/target/s390x/gen-features.c
+++ b/target/s390x/gen-features.c
@@ -575,6 +575,8 @@ static uint16_t full_GEN16_GA1[] = {
     S390_FEAT_BEAR_ENH,
     S390_FEAT_RDP,
     S390_FEAT_PAI,
+    S390_FEAT_UV_FEAT_AP,
+    S390_FEAT_UV_FEAT_AP_INTR,
 };
 
 
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index eb8ca4c780..a963866ef4 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -2308,6 +2308,42 @@ 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 },
@@ -2502,11 +2538,38 @@ 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 :
@@ -2578,6 +2641,13 @@ 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)
-- 
2.41.0