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From:   Matthew Rosato <mjrosato@linux.ibm.com>
To:     linux-s390@vger.kernel.org
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Subject: [PATCH v7 14/22] KVM: s390: mechanism to enable guest zPCI Interpretation
Date:   Fri, 13 May 2022 15:15:01 -0400
Message-Id: <20220513191509.272897-15-mjrosato@linux.ibm.com>
In-Reply-To: <20220513191509.272897-1-mjrosato@linux.ibm.com>
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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>
---
 arch/s390/include/asm/kvm_host.h |  4 ++++
 arch/s390/kvm/kvm-s390.c         | 38 ++++++++++++++++++++++++++++++++
 arch/s390/kvm/kvm-s390.h         | 10 +++++++++
 3 files changed, 52 insertions(+)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index c1518a505060..8e381603b6a7 100644
--- 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 5a0fbfd19c4a..0797661732cc 100644
--- 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 host is configured for PCI and the necessary facilities are
+	 * available, turn on interpretation for the life of this guest
+	 */
+	if (!kvm_s390_pci_interp_allowed())
+		return;
+
+	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;
@@ -3340,6 +3376,8 @@ 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 497d52a83c78..975cffaf13de 100644
--- 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
  *
-- 
2.27.0