KVM: s390: protvirt: Add initial vm and cpu lifecycle handling

This contains 3 main changes:
1. changes in SIE control block handling for secure guests
2. helper functions for create/destroy/unpack secure guests
3. KVM_S390_PV_COMMAND ioctl to allow userspace dealing with secure
machines

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 266 insertions, 0 deletions

diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
new file mode 100644
index 000000000000..e9e020475f4a
--- /dev/null
+++ b/arch/s390/kvm/pv.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hosting Protected Virtual Machines
+ *
+ * Copyright IBM Corp. 2019, 2020
+ *    Author(s): Janosch Frank <frankja@linux.ibm.com>
+ */
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/pagemap.h>
+#include <linux/sched/signal.h>
+#include <asm/pgalloc.h>
+#include <asm/gmap.h>
+#include <asm/uv.h>
+#include <asm/mman.h>
+#include "kvm-s390.h"
+
+int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
+{
+	int cc = 0;
+
+	if (kvm_s390_pv_cpu_get_handle(vcpu)) {
+		cc = uv_cmd_nodata(kvm_s390_pv_cpu_get_handle(vcpu),
+				   UVC_CMD_DESTROY_SEC_CPU, rc, rrc);
+
+		KVM_UV_EVENT(vcpu->kvm, 3,
+			     "PROTVIRT DESTROY VCPU %d: rc %x rrc %x",
+			     vcpu->vcpu_id, *rc, *rrc);
+		WARN_ONCE(cc, "protvirt destroy cpu failed rc %x rrc %x",
+			  *rc, *rrc);
+	}
+	/* Intended memory leak for something that should never happen. */
+	if (!cc)
+		free_pages(vcpu->arch.pv.stor_base,
+			   get_order(uv_info.guest_cpu_stor_len));
+	vcpu->arch.sie_block->pv_handle_cpu = 0;
+	vcpu->arch.sie_block->pv_handle_config = 0;
+	memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv));
+	vcpu->arch.sie_block->sdf = 0;
+	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
+
+	return cc ? EIO : 0;
+}
+
+int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
+{
+	struct uv_cb_csc uvcb = {
+		.header.cmd = UVC_CMD_CREATE_SEC_CPU,
+		.header.len = sizeof(uvcb),
+	};
+	int cc;
+
+	if (kvm_s390_pv_cpu_get_handle(vcpu))
+		return -EINVAL;
+
+	vcpu->arch.pv.stor_base = __get_free_pages(GFP_KERNEL,
+						   get_order(uv_info.guest_cpu_stor_len));
+	if (!vcpu->arch.pv.stor_base)
+		return -ENOMEM;
+
+	/* Input */
+	uvcb.guest_handle = kvm_s390_pv_get_handle(vcpu->kvm);
+	uvcb.num = vcpu->arch.sie_block->icpua;
+	uvcb.state_origin = (u64)vcpu->arch.sie_block;
+	uvcb.stor_origin = (u64)vcpu->arch.pv.stor_base;
+
+	cc = uv_call(0, (u64)&uvcb);
+	*rc = uvcb.header.rc;
+	*rrc = uvcb.header.rrc;
+	KVM_UV_EVENT(vcpu->kvm, 3,
+		     "PROTVIRT CREATE VCPU: cpu %d handle %llx rc %x rrc %x",
+		     vcpu->vcpu_id, uvcb.cpu_handle, uvcb.header.rc,
+		     uvcb.header.rrc);
+
+	if (cc) {
+		u16 dummy;
+
+		kvm_s390_pv_destroy_cpu(vcpu, &dummy, &dummy);
+		return -EIO;
+	}
+
+	/* Output */
+	vcpu->arch.pv.handle = uvcb.cpu_handle;
+	vcpu->arch.sie_block->pv_handle_cpu = uvcb.cpu_handle;
+	vcpu->arch.sie_block->pv_handle_config = kvm_s390_pv_get_handle(vcpu->kvm);
+	vcpu->arch.sie_block->sdf = 2;
+	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
+	return 0;
+}
+
+/* only free resources when the destroy was successful */
+static void kvm_s390_pv_dealloc_vm(struct kvm *kvm)
+{
+	vfree(kvm->arch.pv.stor_var);
+	free_pages(kvm->arch.pv.stor_base,
+		   get_order(uv_info.guest_base_stor_len));
+	memset(&kvm->arch.pv, 0, sizeof(kvm->arch.pv));
+}
+
+static int kvm_s390_pv_alloc_vm(struct kvm *kvm)
+{
+	unsigned long base = uv_info.guest_base_stor_len;
+	unsigned long virt = uv_info.guest_virt_var_stor_len;
+	unsigned long npages = 0, vlen = 0;
+	struct kvm_memory_slot *memslot;
+
+	kvm->arch.pv.stor_var = NULL;
+	kvm->arch.pv.stor_base = __get_free_pages(GFP_KERNEL, get_order(base));
+	if (!kvm->arch.pv.stor_base)
+		return -ENOMEM;
+
+	/*
+	 * Calculate current guest storage for allocation of the
+	 * variable storage, which is based on the length in MB.
+	 *
+	 * Slots are sorted by GFN
+	 */
+	mutex_lock(&kvm->slots_lock);
+	memslot = kvm_memslots(kvm)->memslots;
+	npages = memslot->base_gfn + memslot->npages;
+	mutex_unlock(&kvm->slots_lock);
+
+	kvm->arch.pv.guest_len = npages * PAGE_SIZE;
+
+	/* Allocate variable storage */
+	vlen = ALIGN(virt * ((npages * PAGE_SIZE) / HPAGE_SIZE), PAGE_SIZE);
+	vlen += uv_info.guest_virt_base_stor_len;
+	kvm->arch.pv.stor_var = vzalloc(vlen);
+	if (!kvm->arch.pv.stor_var)
+		goto out_err;
+	return 0;
+
+out_err:
+	kvm_s390_pv_dealloc_vm(kvm);
+	return -ENOMEM;
+}
+
+/* this should not fail, but if it does, we must not free the donated memory */
+int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
+{
+	int cc;
+
+	cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
+			   UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
+	WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
+	atomic_set(&kvm->mm->context.is_protected, 0);
+	KVM_UV_EVENT(kvm, 3, "PROTVIRT DESTROY VM: rc %x rrc %x", *rc, *rrc);
+	WARN_ONCE(cc, "protvirt destroy vm failed rc %x rrc %x", *rc, *rrc);
+	/* Inteded memory leak on "impossible" error */
+	if (!cc)
+		kvm_s390_pv_dealloc_vm(kvm);
+	return cc ? -EIO : 0;
+}
+
+int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
+{
+	struct uv_cb_cgc uvcb = {
+		.header.cmd = UVC_CMD_CREATE_SEC_CONF,
+		.header.len = sizeof(uvcb)
+	};
+	int cc, ret;
+	u16 dummy;
+
+	ret = kvm_s390_pv_alloc_vm(kvm);
+	if (ret)
+		return ret;
+
+	/* Inputs */
+	uvcb.guest_stor_origin = 0; /* MSO is 0 for KVM */
+	uvcb.guest_stor_len = kvm->arch.pv.guest_len;
+	uvcb.guest_asce = kvm->arch.gmap->asce;
+	uvcb.guest_sca = (unsigned long)kvm->arch.sca;
+	uvcb.conf_base_stor_origin = (u64)kvm->arch.pv.stor_base;
+	uvcb.conf_virt_stor_origin = (u64)kvm->arch.pv.stor_var;
+
+	cc = uv_call(0, (u64)&uvcb);
+	*rc = uvcb.header.rc;
+	*rrc = uvcb.header.rrc;
+	KVM_UV_EVENT(kvm, 3, "PROTVIRT CREATE VM: handle %llx len %llx rc %x rrc %x",
+		     uvcb.guest_handle, uvcb.guest_stor_len, *rc, *rrc);
+
+	/* Outputs */
+	kvm->arch.pv.handle = uvcb.guest_handle;
+
+	if (cc) {
+		if (uvcb.header.rc & UVC_RC_NEED_DESTROY)
+			kvm_s390_pv_deinit_vm(kvm, &dummy, &dummy);
+		else
+			kvm_s390_pv_dealloc_vm(kvm);
+		return -EIO;
+	}
+	kvm->arch.gmap->guest_handle = uvcb.guest_handle;
+	atomic_set(&kvm->mm->context.is_protected, 1);
+	return 0;
+}
+
+int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
+			      u16 *rrc)
+{
+	struct uv_cb_ssc uvcb = {
+		.header.cmd = UVC_CMD_SET_SEC_CONF_PARAMS,
+		.header.len = sizeof(uvcb),
+		.sec_header_origin = (u64)hdr,
+		.sec_header_len = length,
+		.guest_handle = kvm_s390_pv_get_handle(kvm),
+	};
+	int cc = uv_call(0, (u64)&uvcb);
+
+	*rc = uvcb.header.rc;
+	*rrc = uvcb.header.rrc;
+	KVM_UV_EVENT(kvm, 3, "PROTVIRT VM SET PARMS: rc %x rrc %x",
+		     *rc, *rrc);
+	return cc ? -EINVAL : 0;
+}
+
+static int unpack_one(struct kvm *kvm, unsigned long addr, u64 tweak,
+		      u64 offset, u16 *rc, u16 *rrc)
+{
+	struct uv_cb_unp uvcb = {
+		.header.cmd = UVC_CMD_UNPACK_IMG,
+		.header.len = sizeof(uvcb),
+		.guest_handle = kvm_s390_pv_get_handle(kvm),
+		.gaddr = addr,
+		.tweak[0] = tweak,
+		.tweak[1] = offset,
+	};
+	int ret = gmap_make_secure(kvm->arch.gmap, addr, &uvcb);
+
+	*rc = uvcb.header.rc;
+	*rrc = uvcb.header.rrc;
+
+	if (ret && ret != -EAGAIN)
+		KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: failed addr %llx with rc %x rrc %x",
+			     uvcb.gaddr, *rc, *rrc);
+	return ret;
+}
+
+int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
+		       unsigned long tweak, u16 *rc, u16 *rrc)
+{
+	u64 offset = 0;
+	int ret = 0;
+
+	if (addr & ~PAGE_MASK || !size || size & ~PAGE_MASK)
+		return -EINVAL;
+
+	KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: start addr %lx size %lx",
+		     addr, size);
+
+	while (offset < size) {
+		ret = unpack_one(kvm, addr, tweak, offset, rc, rrc);
+		if (ret == -EAGAIN) {
+			cond_resched();
+			if (fatal_signal_pending(current))
+				break;
+			continue;
+		}
+		if (ret)
+			break;
+		addr += PAGE_SIZE;
+		offset += PAGE_SIZE;
+	}
+	if (!ret)
+		KVM_UV_EVENT(kvm, 3, "%s", "PROTVIRT VM UNPACK: successful");
+	return ret;
+}