KVM: s390: mechanism to enable guest zPCI Interpretation

The guest must have access to certain facilities in order to allow
interpretive execution of zPCI instructions and adapter event
notifications.  However, there are some cases where a guest might
disable interpretation -- provide a mechanism via which we can defer
enabling the associated zPCI interpretation facilities until the guest
indicates it wishes to use them.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606203325.110625-15-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index c1518a505060011a920194d76a9e849c84013baa..8e381603b6a787fbe05d95d76e7154b1ebb9468f 100644 (file)
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -254,7 +254,10 @@ struct kvm_s390_sie_block {
 #define ECB2_IEP       0x20
 #define ECB2_PFMFI     0x08
 #define ECB2_ESCA      0x04
+#define ECB2_ZPCI_LSI  0x02
        __u8    ecb2;                   /* 0x0062 */
+#define ECB3_AISI      0x20
+#define ECB3_AISII     0x10
 #define ECB3_DEA 0x08
 #define ECB3_AES 0x04
 #define ECB3_RI  0x01
@@ -940,6 +943,7 @@ struct kvm_arch{
        int use_cmma;
        int use_pfmfi;
        int use_skf;
+       int use_zpci_interp;
        int user_cpu_state_ctrl;
        int user_sigp;
        int user_stsi;

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index d96c9be0480bf88f47f61665b5de236def35d4c1..a66da3f661140273701f3680c834cdac08846fff 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1031,6 +1031,42 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
        return 0;
 }
 
+static void kvm_s390_vcpu_pci_setup(struct kvm_vcpu *vcpu)
+{
+       /* Only set the ECB bits after guest requests zPCI interpretation */
+       if (!vcpu->kvm->arch.use_zpci_interp)
+               return;
+
+       vcpu->arch.sie_block->ecb2 |= ECB2_ZPCI_LSI;
+       vcpu->arch.sie_block->ecb3 |= ECB3_AISII + ECB3_AISI;
+}
+
+void kvm_s390_vcpu_pci_enable_interp(struct kvm *kvm)
+{
+       struct kvm_vcpu *vcpu;
+       unsigned long i;
+
+       lockdep_assert_held(&kvm->lock);
+
+       if (!kvm_s390_pci_interp_allowed())
+               return;
+
+       /*
+        * If host is configured for PCI and the necessary facilities are
+        * available, turn on interpretation for the life of this guest
+        */
+       kvm->arch.use_zpci_interp = 1;
+
+       kvm_s390_vcpu_block_all(kvm);
+
+       kvm_for_each_vcpu(i, vcpu, kvm) {
+               kvm_s390_vcpu_pci_setup(vcpu);
+               kvm_s390_sync_request(KVM_REQ_VSIE_RESTART, vcpu);
+       }
+
+       kvm_s390_vcpu_unblock_all(kvm);
+}
+
 static void kvm_s390_sync_request_broadcast(struct kvm *kvm, int req)
 {
        unsigned long cx;
@@ -3336,6 +3372,8 @@ static int kvm_s390_vcpu_setup(struct kvm_vcpu *vcpu)
 
        kvm_s390_vcpu_crypto_setup(vcpu);
 
+       kvm_s390_vcpu_pci_setup(vcpu);
+
        mutex_lock(&vcpu->kvm->lock);
        if (kvm_s390_pv_is_protected(vcpu->kvm)) {
                rc = kvm_s390_pv_create_cpu(vcpu, &uvrc, &uvrrc);

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 497d52a83c7827515c71cb4f4c29e3e5e3db8aac..975cffaf13de6786fc43eac8c9fec2cfae7c1c3a 100644 (file)
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -507,6 +507,16 @@ void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu,
  */
 void kvm_s390_vcpu_crypto_reset_all(struct kvm *kvm);
 
+/**
+ * kvm_s390_vcpu_pci_enable_interp
+ *
+ * Set the associated PCI attributes for each vcpu to allow for zPCI Load/Store
+ * interpretation as well as adapter interruption forwarding.
+ *
+ * @kvm: the KVM guest
+ */
+void kvm_s390_vcpu_pci_enable_interp(struct kvm *kvm);
+
 /**
  * diag9c_forwarding_hz
  *