[S390] use gmap address spaces for kvm guest images

This patch switches kvm from using (Qemu's) user address space to
Martin's gmap address space. This way QEMU does not have to use a
linker script in order to fit large guests at low addresses in its
address space.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/kvm_host.h

@@ -227,6 +227,7 @@ struct kvm_vcpu_arch {
 		struct cpuid	cpu_id;
 		u64		stidp_data;
 	};
+	struct gmap *gmap;
 };
 
 struct kvm_vm_stat {
@@ -237,6 +238,7 @@ struct kvm_arch{
 	struct sca_block *sca;
 	debug_info_t *dbf;
 	struct kvm_s390_float_interrupt float_int;
+	struct gmap *gmap;
 };
 
 extern int sie64a(struct kvm_s390_sie_block *, unsigned long *);

arch/s390/kvm/intercept.c

@@ -160,6 +160,7 @@ static int handle_stop(struct kvm_vcpu *vcpu)
 
 static int handle_validity(struct kvm_vcpu *vcpu)
 {
+	unsigned long vmaddr;
 	int viwhy = vcpu->arch.sie_block->ipb >> 16;
 	int rc;
 
@@ -170,12 +171,27 @@ static int handle_validity(struct kvm_vcpu *vcpu)
 			 vcpu->arch.sie_block->gmsor +
 			 vcpu->arch.sie_block->prefix,
 			 2*PAGE_SIZE);
-		if (rc)
+		if (rc) {
 			/* user will receive sigsegv, exit to user */
 			rc = -EOPNOTSUPP;
+			goto out;
+		}
+		vmaddr = gmap_fault(vcpu->arch.sie_block->prefix,
+				    vcpu->arch.gmap);
+		if (IS_ERR_VALUE(vmaddr)) {
+			rc = -EOPNOTSUPP;
+			goto out;
+		}
+		vmaddr = gmap_fault(vcpu->arch.sie_block->prefix + PAGE_SIZE,
+				    vcpu->arch.gmap);
+		if (IS_ERR_VALUE(vmaddr)) {
+			rc = -EOPNOTSUPP;
+			goto out;
+		}
 	} else
 		rc = -EOPNOTSUPP;
 
+out:
 	if (rc)
 		VCPU_EVENT(vcpu, 2, "unhandled validity intercept code %d",
 			   viwhy);

arch/s390/kvm/kvm-s390.c

@@ -190,7 +190,13 @@ int kvm_arch_init_vm(struct kvm *kvm)
 	debug_register_view(kvm->arch.dbf, &debug_sprintf_view);
 	VM_EVENT(kvm, 3, "%s", "vm created");
 
+	kvm->arch.gmap = gmap_alloc(current->mm);
+	if (!kvm->arch.gmap)
+		goto out_nogmap;
+
 	return 0;
+out_nogmap:
+	debug_unregister(kvm->arch.dbf);
 out_nodbf:
 	free_page((unsigned long)(kvm->arch.sca));
 out_err:
@@ -235,11 +241,13 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 	kvm_free_vcpus(kvm);
 	free_page((unsigned long)(kvm->arch.sca));
 	debug_unregister(kvm->arch.dbf);
+	gmap_free(kvm->arch.gmap);
 }
 
 /* Section: vcpu related */
 int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 {
+	vcpu->arch.gmap = vcpu->kvm->arch.gmap;
 	return 0;
 }
 
@@ -285,7 +293,7 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
 
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 {
-	atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH);
+	atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH | CPUSTAT_SM);
 	set_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests);
 	vcpu->arch.sie_block->ecb   = 6;
 	vcpu->arch.sie_block->eca   = 0xC1002001U;
@@ -454,6 +462,7 @@ static void __vcpu_run(struct kvm_vcpu *vcpu)
 	local_irq_disable();
 	kvm_guest_enter();
 	local_irq_enable();
+	gmap_enable(vcpu->arch.gmap);
 	VCPU_EVENT(vcpu, 6, "entering sie flags %x",
 		   atomic_read(&vcpu->arch.sie_block->cpuflags));
 	if (sie64a(vcpu->arch.sie_block, vcpu->arch.guest_gprs)) {
@@ -462,6 +471,7 @@ static void __vcpu_run(struct kvm_vcpu *vcpu)
 	}
 	VCPU_EVENT(vcpu, 6, "exit sie icptcode %d",
 		   vcpu->arch.sie_block->icptcode);
+	gmap_disable(vcpu->arch.gmap);
 	local_irq_disable();
 	kvm_guest_exit();
 	local_irq_enable();
@@ -479,13 +489,6 @@ rerun_vcpu:
 		if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
 			kvm_s390_vcpu_set_mem(vcpu);
 
-	/* verify, that memory has been registered */
-	if (!vcpu->arch.sie_block->gmslm) {
-		vcpu_put(vcpu);
-		VCPU_EVENT(vcpu, 3, "%s", "no memory registered to run vcpu");
-		return -EINVAL;
-	}
-
 	if (vcpu->sigset_active)
 		sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
 
@@ -681,10 +684,10 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	if (mem->guest_phys_addr)
 		return -EINVAL;
 
-	if (mem->userspace_addr & (PAGE_SIZE - 1))
+	if (mem->userspace_addr & 0xffffful)
 		return -EINVAL;
 
-	if (mem->memory_size & (PAGE_SIZE - 1))
+	if (mem->memory_size & 0xffffful)
 		return -EINVAL;
 
 	if (!user_alloc)
@@ -698,15 +701,22 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 				struct kvm_memory_slot old,
 				int user_alloc)
 {
-	int i;
+	int i, rc;
 	struct kvm_vcpu *vcpu;
 
+
+	rc = gmap_map_segment(kvm->arch.gmap, mem->userspace_addr,
+		mem->guest_phys_addr, mem->memory_size);
+	if (rc)
+		return;
+
 	/* request update of sie control block for all available vcpus */
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		if (test_and_set_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
 			continue;
 		kvm_s390_inject_sigp_stop(vcpu, ACTION_RELOADVCPU_ON_STOP);
 	}
+	return;
 }
 
 void kvm_arch_flush_shadow(struct kvm *kvm)