4 files changed, 32 insertions, 2 deletions

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 8e5daf7a76ce..876173ca815f 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -28,7 +28,7 @@
 
 #define KVM_S390_BSCA_CPU_SLOTS 64
 #define KVM_S390_ESCA_CPU_SLOTS 248
-#define KVM_MAX_VCPUS KVM_S390_ESCA_CPU_SLOTS
+#define KVM_MAX_VCPUS 255
 #define KVM_USER_MEM_SLOTS 32
 
 /*
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 353e0b78e667..be4db07f70d3 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -42,6 +42,7 @@ static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
 	if (!(atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_ECALL_PEND))
 		return 0;
 
+	BUG_ON(!kvm_s390_use_sca_entries());
 	read_lock(&vcpu->kvm->arch.sca_lock);
 	if (vcpu->kvm->arch.use_esca) {
 		struct esca_block *sca = vcpu->kvm->arch.sca;
@@ -70,6 +71,7 @@ static int sca_inject_ext_call(struct kvm_vcpu *vcpu, int src_id)
 {
 	int expect, rc;
 
+	BUG_ON(!kvm_s390_use_sca_entries());
 	read_lock(&vcpu->kvm->arch.sca_lock);
 	if (vcpu->kvm->arch.use_esca) {
 		struct esca_block *sca = vcpu->kvm->arch.sca;
@@ -111,6 +113,8 @@ static void sca_clear_ext_call(struct kvm_vcpu *vcpu)
 	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
 	int rc, expect;
 
+	if (!kvm_s390_use_sca_entries())
+		return;
 	atomic_andnot(CPUSTAT_ECALL_PEND, li->cpuflags);
 	read_lock(&vcpu->kvm->arch.sca_lock);
 	if (vcpu->kvm->arch.use_esca) {
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 892abf4653a8..3a628eb3156f 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -376,7 +376,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_NR_VCPUS:
 	case KVM_CAP_MAX_VCPUS:
 		r = KVM_S390_BSCA_CPU_SLOTS;
-		if (sclp.has_esca && sclp.has_64bscao)
+		if (!kvm_s390_use_sca_entries())
+			r = KVM_MAX_VCPUS;
+		else if (sclp.has_esca && sclp.has_64bscao)
 			r = KVM_S390_ESCA_CPU_SLOTS;
 		break;
 	case KVM_CAP_NR_MEMSLOTS:
@@ -1553,6 +1555,8 @@ static int __kvm_ucontrol_vcpu_init(struct kvm_vcpu *vcpu)
 
 static void sca_del_vcpu(struct kvm_vcpu *vcpu)
 {
+	if (!kvm_s390_use_sca_entries())
+		return;
 	read_lock(&vcpu->kvm->arch.sca_lock);
 	if (vcpu->kvm->arch.use_esca) {
 		struct esca_block *sca = vcpu->kvm->arch.sca;
@@ -1570,6 +1574,13 @@ static void sca_del_vcpu(struct kvm_vcpu *vcpu)
 
 static void sca_add_vcpu(struct kvm_vcpu *vcpu)
 {
+	if (!kvm_s390_use_sca_entries()) {
+		struct bsca_block *sca = vcpu->kvm->arch.sca;
+
+		/* we still need the basic sca for the ipte control */
+		vcpu->arch.sie_block->scaoh = (__u32)(((__u64)sca) >> 32);
+		vcpu->arch.sie_block->scaol = (__u32)(__u64)sca;
+	}
 	read_lock(&vcpu->kvm->arch.sca_lock);
 	if (vcpu->kvm->arch.use_esca) {
 		struct esca_block *sca = vcpu->kvm->arch.sca;
@@ -1650,6 +1661,11 @@ static int sca_can_add_vcpu(struct kvm *kvm, unsigned int id)
 {
 	int rc;
 
+	if (!kvm_s390_use_sca_entries()) {
+		if (id < KVM_MAX_VCPUS)
+			return true;
+		return false;
+	}
 	if (id < KVM_S390_BSCA_CPU_SLOTS)
 		return true;
 	if (!sclp.has_esca || !sclp.has_64bscao)
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 9995cab41950..3a4e97f1a9e6 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -20,6 +20,7 @@
 #include <linux/kvm_host.h>
 #include <asm/facility.h>
 #include <asm/processor.h>
+#include <asm/sclp.h>
 
 typedef int (*intercept_handler_t)(struct kvm_vcpu *vcpu);
 
@@ -387,4 +388,13 @@ static inline union ipte_control *kvm_s390_get_ipte_control(struct kvm *kvm)
 
 	return &sca->ipte_control;
 }
+static inline int kvm_s390_use_sca_entries(void)
+{
+	/*
+	 * Without SIGP interpretation, only SRS interpretation (if available)
+	 * might use the entries. By not setting the entries and keeping them
+	 * invalid, hardware will not access them but intercept.
+	 */
+	return sclp.has_sigpif;
+}
 #endif