Linux-libre 4.8.2-gnupck-4.8.2-gnu

1 files changed, 1091 insertions, 0 deletions

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
new file mode 100644
index 000000000..d8673e243
--- /dev/null
+++ b/arch/s390/kvm/vsie.c
@@ -0,0 +1,1091 @@
+/*
+ * kvm nested virtualization support for s390x
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
+ */
+#include <linux/vmalloc.h>
+#include <linux/kvm_host.h>
+#include <linux/bug.h>
+#include <linux/list.h>
+#include <linux/bitmap.h>
+#include <asm/gmap.h>
+#include <asm/mmu_context.h>
+#include <asm/sclp.h>
+#include <asm/nmi.h>
+#include <asm/dis.h>
+#include "kvm-s390.h"
+#include "gaccess.h"
+
+struct vsie_page {
+	struct kvm_s390_sie_block scb_s;	/* 0x0000 */
+	/* the pinned originial scb */
+	struct kvm_s390_sie_block *scb_o;	/* 0x0200 */
+	/* the shadow gmap in use by the vsie_page */
+	struct gmap *gmap;			/* 0x0208 */
+	/* address of the last reported fault to guest2 */
+	unsigned long fault_addr;		/* 0x0210 */
+	__u8 reserved[0x0700 - 0x0218];		/* 0x0218 */
+	struct kvm_s390_crypto_cb crycb;	/* 0x0700 */
+	__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE];	/* 0x0800 */
+} __packed;
+
+/* trigger a validity icpt for the given scb */
+static int set_validity_icpt(struct kvm_s390_sie_block *scb,
+			     __u16 reason_code)
+{
+	scb->ipa = 0x1000;
+	scb->ipb = ((__u32) reason_code) << 16;
+	scb->icptcode = ICPT_VALIDITY;
+	return 1;
+}
+
+/* mark the prefix as unmapped, this will block the VSIE */
+static void prefix_unmapped(struct vsie_page *vsie_page)
+{
+	atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
+}
+
+/* mark the prefix as unmapped and wait until the VSIE has been left */
+static void prefix_unmapped_sync(struct vsie_page *vsie_page)
+{
+	prefix_unmapped(vsie_page);
+	if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
+		atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
+	while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
+		cpu_relax();
+}
+
+/* mark the prefix as mapped, this will allow the VSIE to run */
+static void prefix_mapped(struct vsie_page *vsie_page)
+{
+	atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
+}
+
+/* test if the prefix is mapped into the gmap shadow */
+static int prefix_is_mapped(struct vsie_page *vsie_page)
+{
+	return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST);
+}
+
+/* copy the updated intervention request bits into the shadow scb */
+static void update_intervention_requests(struct vsie_page *vsie_page)
+{
+	const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
+	int cpuflags;
+
+	cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
+	atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
+	atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
+}
+
+/* shadow (filter and validate) the cpuflags  */
+static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	int newflags, cpuflags = atomic_read(&scb_o->cpuflags);
+
+	/* we don't allow ESA/390 guests */
+	if (!(cpuflags & CPUSTAT_ZARCH))
+		return set_validity_icpt(scb_s, 0x0001U);
+
+	if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
+		return set_validity_icpt(scb_s, 0x0001U);
+	else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
+		return set_validity_icpt(scb_s, 0x0007U);
+
+	/* intervention requests will be set later */
+	newflags = CPUSTAT_ZARCH;
+	if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8))
+		newflags |= CPUSTAT_GED;
+	if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) {
+		if (cpuflags & CPUSTAT_GED)
+			return set_validity_icpt(scb_s, 0x0001U);
+		newflags |= CPUSTAT_GED2;
+	}
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE))
+		newflags |= cpuflags & CPUSTAT_P;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS))
+		newflags |= cpuflags & CPUSTAT_SM;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS))
+		newflags |= cpuflags & CPUSTAT_IBS;
+
+	atomic_set(&scb_s->cpuflags, newflags);
+	return 0;
+}
+
+/*
+ * Create a shadow copy of the crycb block and setup key wrapping, if
+ * requested for guest 3 and enabled for guest 2.
+ *
+ * We only accept format-1 (no AP in g2), but convert it into format-2
+ * There is nothing to do for format-0.
+ *
+ * Returns: - 0 if shadowed or nothing to do
+ *          - > 0 if control has to be given to guest 2
+ */
+static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	u32 crycb_addr = scb_o->crycbd & 0x7ffffff8U;
+	unsigned long *b1, *b2;
+	u8 ecb3_flags;
+
+	scb_s->crycbd = 0;
+	if (!(scb_o->crycbd & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1))
+		return 0;
+	/* format-1 is supported with message-security-assist extension 3 */
+	if (!test_kvm_facility(vcpu->kvm, 76))
+		return 0;
+	/* we may only allow it if enabled for guest 2 */
+	ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
+		     (ECB3_AES | ECB3_DEA);
+	if (!ecb3_flags)
+		return 0;
+
+	if ((crycb_addr & PAGE_MASK) != ((crycb_addr + 128) & PAGE_MASK))
+		return set_validity_icpt(scb_s, 0x003CU);
+	else if (!crycb_addr)
+		return set_validity_icpt(scb_s, 0x0039U);
+
+	/* copy only the wrapping keys */
+	if (read_guest_real(vcpu, crycb_addr + 72, &vsie_page->crycb, 56))
+		return set_validity_icpt(scb_s, 0x0035U);
+
+	scb_s->ecb3 |= ecb3_flags;
+	scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT1 |
+			CRYCB_FORMAT2;
+
+	/* xor both blocks in one run */
+	b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
+	b2 = (unsigned long *)
+			    vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask;
+	/* as 56%8 == 0, bitmap_xor won't overwrite any data */
+	bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56);
+	return 0;
+}
+
+/* shadow (round up/down) the ibc to avoid validity icpt */
+static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	__u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU;
+
+	scb_s->ibc = 0;
+	/* ibc installed in g2 and requested for g3 */
+	if (vcpu->kvm->arch.model.ibc && (scb_o->ibc & 0x0fffU)) {
+		scb_s->ibc = scb_o->ibc & 0x0fffU;
+		/* takte care of the minimum ibc level of the machine */
+		if (scb_s->ibc < min_ibc)
+			scb_s->ibc = min_ibc;
+		/* take care of the maximum ibc level set for the guest */
+		if (scb_s->ibc > vcpu->kvm->arch.model.ibc)
+			scb_s->ibc = vcpu->kvm->arch.model.ibc;
+	}
+}
+
+/* unshadow the scb, copying parameters back to the real scb */
+static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+
+	/* interception */
+	scb_o->icptcode = scb_s->icptcode;
+	scb_o->icptstatus = scb_s->icptstatus;
+	scb_o->ipa = scb_s->ipa;
+	scb_o->ipb = scb_s->ipb;
+	scb_o->gbea = scb_s->gbea;
+
+	/* timer */
+	scb_o->cputm = scb_s->cputm;
+	scb_o->ckc = scb_s->ckc;
+	scb_o->todpr = scb_s->todpr;
+
+	/* guest state */
+	scb_o->gpsw = scb_s->gpsw;
+	scb_o->gg14 = scb_s->gg14;
+	scb_o->gg15 = scb_s->gg15;
+	memcpy(scb_o->gcr, scb_s->gcr, 128);
+	scb_o->pp = scb_s->pp;
+
+	/* interrupt intercept */
+	switch (scb_s->icptcode) {
+	case ICPT_PROGI:
+	case ICPT_INSTPROGI:
+	case ICPT_EXTINT:
+		memcpy((void *)((u64)scb_o + 0xc0),
+		       (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
+		break;
+	case ICPT_PARTEXEC:
+		/* MVPG only */
+		memcpy((void *)((u64)scb_o + 0xc0),
+		       (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0);
+		break;
+	}
+
+	if (scb_s->ihcpu != 0xffffU)
+		scb_o->ihcpu = scb_s->ihcpu;
+}
+
+/*
+ * Setup the shadow scb by copying and checking the relevant parts of the g2
+ * provided scb.
+ *
+ * Returns: - 0 if the scb has been shadowed
+ *          - > 0 if control has to be given to guest 2
+ */
+static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	bool had_tx = scb_s->ecb & 0x10U;
+	unsigned long new_mso = 0;
+	int rc;
+
+	/* make sure we don't have any leftovers when reusing the scb */
+	scb_s->icptcode = 0;
+	scb_s->eca = 0;
+	scb_s->ecb = 0;
+	scb_s->ecb2 = 0;
+	scb_s->ecb3 = 0;
+	scb_s->ecd = 0;
+	scb_s->fac = 0;
+
+	rc = prepare_cpuflags(vcpu, vsie_page);
+	if (rc)
+		goto out;
+
+	/* timer */
+	scb_s->cputm = scb_o->cputm;
+	scb_s->ckc = scb_o->ckc;
+	scb_s->todpr = scb_o->todpr;
+	scb_s->epoch = scb_o->epoch;
+
+	/* guest state */
+	scb_s->gpsw = scb_o->gpsw;
+	scb_s->gg14 = scb_o->gg14;
+	scb_s->gg15 = scb_o->gg15;
+	memcpy(scb_s->gcr, scb_o->gcr, 128);
+	scb_s->pp = scb_o->pp;
+
+	/* interception / execution handling */
+	scb_s->gbea = scb_o->gbea;
+	scb_s->lctl = scb_o->lctl;
+	scb_s->svcc = scb_o->svcc;
+	scb_s->ictl = scb_o->ictl;
+	/*
+	 * SKEY handling functions can't deal with false setting of PTE invalid
+	 * bits. Therefore we cannot provide interpretation and would later
+	 * have to provide own emulation handlers.
+	 */
+	scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
+	scb_s->icpua = scb_o->icpua;
+
+	if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_SM))
+		new_mso = scb_o->mso & 0xfffffffffff00000UL;
+	/* if the hva of the prefix changes, we have to remap the prefix */
+	if (scb_s->mso != new_mso || scb_s->prefix != scb_o->prefix)
+		prefix_unmapped(vsie_page);
+	 /* SIE will do mso/msl validity and exception checks for us */
+	scb_s->msl = scb_o->msl & 0xfffffffffff00000UL;
+	scb_s->mso = new_mso;
+	scb_s->prefix = scb_o->prefix;
+
+	/* We have to definetly flush the tlb if this scb never ran */
+	if (scb_s->ihcpu != 0xffffU)
+		scb_s->ihcpu = scb_o->ihcpu;
+
+	/* MVPG and Protection Exception Interpretation are always available */
+	scb_s->eca |= scb_o->eca & 0x01002000U;
+	/* Host-protection-interruption introduced with ESOP */
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_ESOP))
+		scb_s->ecb |= scb_o->ecb & 0x02U;
+	/* transactional execution */
+	if (test_kvm_facility(vcpu->kvm, 73)) {
+		/* remap the prefix is tx is toggled on */
+		if ((scb_o->ecb & 0x10U) && !had_tx)
+			prefix_unmapped(vsie_page);
+		scb_s->ecb |= scb_o->ecb & 0x10U;
+	}
+	/* SIMD */
+	if (test_kvm_facility(vcpu->kvm, 129)) {
+		scb_s->eca |= scb_o->eca & 0x00020000U;
+		scb_s->ecd |= scb_o->ecd & 0x20000000U;
+	}
+	/* Run-time-Instrumentation */
+	if (test_kvm_facility(vcpu->kvm, 64))
+		scb_s->ecb3 |= scb_o->ecb3 & 0x01U;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF))
+		scb_s->eca |= scb_o->eca & 0x00000001U;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB))
+		scb_s->eca |= scb_o->eca & 0x40000000U;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
+		scb_s->eca |= scb_o->eca & 0x80000000U;
+
+	prepare_ibc(vcpu, vsie_page);
+	rc = shadow_crycb(vcpu, vsie_page);
+out:
+	if (rc)
+		unshadow_scb(vcpu, vsie_page);
+	return rc;
+}
+
+void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
+				 unsigned long end)
+{
+	struct kvm *kvm = gmap->private;
+	struct vsie_page *cur;
+	unsigned long prefix;
+	struct page *page;
+	int i;
+
+	if (!gmap_is_shadow(gmap))
+		return;
+	if (start >= 1UL << 31)
+		/* We are only interested in prefix pages */
+		return;
+
+	/*
+	 * Only new shadow blocks are added to the list during runtime,
+	 * therefore we can safely reference them all the time.
+	 */
+	for (i = 0; i < kvm->arch.vsie.page_count; i++) {
+		page = READ_ONCE(kvm->arch.vsie.pages[i]);
+		if (!page)
+			continue;
+		cur = page_to_virt(page);
+		if (READ_ONCE(cur->gmap) != gmap)
+			continue;
+		prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
+		/* with mso/msl, the prefix lies at an offset */
+		prefix += cur->scb_s.mso;
+		if (prefix <= end && start <= prefix + 2 * PAGE_SIZE - 1)
+			prefix_unmapped_sync(cur);
+	}
+}
+
+/*
+ * Map the first prefix page and if tx is enabled also the second prefix page.
+ *
+ * The prefix will be protected, a gmap notifier will inform about unmaps.
+ * The shadow scb must not be executed until the prefix is remapped, this is
+ * guaranteed by properly handling PROG_REQUEST.
+ *
+ * Returns: - 0 on if successfully mapped or already mapped
+ *          - > 0 if control has to be given to guest 2
+ *          - -EAGAIN if the caller can retry immediately
+ *          - -ENOMEM if out of memory
+ */
+static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
+	int rc;
+
+	if (prefix_is_mapped(vsie_page))
+		return 0;
+
+	/* mark it as mapped so we can catch any concurrent unmappers */
+	prefix_mapped(vsie_page);
+
+	/* with mso/msl, the prefix lies at offset *mso* */
+	prefix += scb_s->mso;
+
+	rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix);
+	if (!rc && (scb_s->ecb & 0x10U))
+		rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
+					   prefix + PAGE_SIZE);
+	/*
+	 * We don't have to mprotect, we will be called for all unshadows.
+	 * SIE will detect if protection applies and trigger a validity.
+	 */
+	if (rc)
+		prefix_unmapped(vsie_page);
+	if (rc > 0 || rc == -EFAULT)
+		rc = set_validity_icpt(scb_s, 0x0037U);
+	return rc;
+}
+
+/*
+ * Pin the guest page given by gpa and set hpa to the pinned host address.
+ * Will always be pinned writable.
+ *
+ * Returns: - 0 on success
+ *          - -EINVAL if the gpa is not valid guest storage
+ *          - -ENOMEM if out of memory
+ */
+static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
+{
+	struct page *page;
+	hva_t hva;
+	int rc;
+
+	hva = gfn_to_hva(kvm, gpa_to_gfn(gpa));
+	if (kvm_is_error_hva(hva))
+		return -EINVAL;
+	rc = get_user_pages_fast(hva, 1, 1, &page);
+	if (rc < 0)
+		return rc;
+	else if (rc != 1)
+		return -ENOMEM;
+	*hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
+	return 0;
+}
+
+/* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */
+static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa)
+{
+	struct page *page;
+
+	page = virt_to_page(hpa);
+	set_page_dirty_lock(page);
+	put_page(page);
+	/* mark the page always as dirty for migration */
+	mark_page_dirty(kvm, gpa_to_gfn(gpa));
+}
+
+/* unpin all blocks previously pinned by pin_blocks(), marking them dirty */
+static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	hpa_t hpa;
+	gpa_t gpa;
+
+	hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol;
+	if (hpa) {
+		gpa = scb_o->scaol & ~0xfUL;
+		if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
+			gpa |= (u64) scb_o->scaoh << 32;
+		unpin_guest_page(vcpu->kvm, gpa, hpa);
+		scb_s->scaol = 0;
+		scb_s->scaoh = 0;
+	}
+
+	hpa = scb_s->itdba;
+	if (hpa) {
+		gpa = scb_o->itdba & ~0xffUL;
+		unpin_guest_page(vcpu->kvm, gpa, hpa);
+		scb_s->itdba = 0;
+	}
+
+	hpa = scb_s->gvrd;
+	if (hpa) {
+		gpa = scb_o->gvrd & ~0x1ffUL;
+		unpin_guest_page(vcpu->kvm, gpa, hpa);
+		scb_s->gvrd = 0;
+	}
+
+	hpa = scb_s->riccbd;
+	if (hpa) {
+		gpa = scb_o->riccbd & ~0x3fUL;
+		unpin_guest_page(vcpu->kvm, gpa, hpa);
+		scb_s->riccbd = 0;
+	}
+}
+
+/*
+ * Instead of shadowing some blocks, we can simply forward them because the
+ * addresses in the scb are 64 bit long.
+ *
+ * This works as long as the data lies in one page. If blocks ever exceed one
+ * page, we have to fall back to shadowing.
+ *
+ * As we reuse the sca, the vcpu pointers contained in it are invalid. We must
+ * therefore not enable any facilities that access these pointers (e.g. SIGPIF).
+ *
+ * Returns: - 0 if all blocks were pinned.
+ *          - > 0 if control has to be given to guest 2
+ *          - -ENOMEM if out of memory
+ */
+static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	hpa_t hpa;
+	gpa_t gpa;
+	int rc = 0;
+
+	gpa = scb_o->scaol & ~0xfUL;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
+		gpa |= (u64) scb_o->scaoh << 32;
+	if (gpa) {
+		if (!(gpa & ~0x1fffUL))
+			rc = set_validity_icpt(scb_s, 0x0038U);
+		else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu))
+			rc = set_validity_icpt(scb_s, 0x0011U);
+		else if ((gpa & PAGE_MASK) !=
+			 ((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK))
+			rc = set_validity_icpt(scb_s, 0x003bU);
+		if (!rc) {
+			rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
+			if (rc == -EINVAL)
+				rc = set_validity_icpt(scb_s, 0x0034U);
+		}
+		if (rc)
+			goto unpin;
+		scb_s->scaoh = (u32)((u64)hpa >> 32);
+		scb_s->scaol = (u32)(u64)hpa;
+	}
+
+	gpa = scb_o->itdba & ~0xffUL;
+	if (gpa && (scb_s->ecb & 0x10U)) {
+		if (!(gpa & ~0x1fffU)) {
+			rc = set_validity_icpt(scb_s, 0x0080U);
+			goto unpin;
+		}
+		/* 256 bytes cannot cross page boundaries */
+		rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
+		if (rc == -EINVAL)
+			rc = set_validity_icpt(scb_s, 0x0080U);
+		if (rc)
+			goto unpin;
+		scb_s->itdba = hpa;
+	}
+
+	gpa = scb_o->gvrd & ~0x1ffUL;
+	if (gpa && (scb_s->eca & 0x00020000U) &&
+	    !(scb_s->ecd & 0x20000000U)) {
+		if (!(gpa & ~0x1fffUL)) {
+			rc = set_validity_icpt(scb_s, 0x1310U);
+			goto unpin;
+		}
+		/*
+		 * 512 bytes vector registers cannot cross page boundaries
+		 * if this block gets bigger, we have to shadow it.
+		 */
+		rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
+		if (rc == -EINVAL)
+			rc = set_validity_icpt(scb_s, 0x1310U);
+		if (rc)
+			goto unpin;
+		scb_s->gvrd = hpa;
+	}
+
+	gpa = scb_o->riccbd & ~0x3fUL;
+	if (gpa && (scb_s->ecb3 & 0x01U)) {
+		if (!(gpa & ~0x1fffUL)) {
+			rc = set_validity_icpt(scb_s, 0x0043U);
+			goto unpin;
+		}
+		/* 64 bytes cannot cross page boundaries */
+		rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
+		if (rc == -EINVAL)
+			rc = set_validity_icpt(scb_s, 0x0043U);
+		/* Validity 0x0044 will be checked by SIE */
+		if (rc)
+			goto unpin;
+		scb_s->riccbd = hpa;
+	}
+	return 0;
+unpin:
+	unpin_blocks(vcpu, vsie_page);
+	return rc;
+}
+
+/* unpin the scb provided by guest 2, marking it as dirty */
+static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
+		      gpa_t gpa)
+{
+	hpa_t hpa = (hpa_t) vsie_page->scb_o;
+
+	if (hpa)
+		unpin_guest_page(vcpu->kvm, gpa, hpa);
+	vsie_page->scb_o = NULL;
+}
+
+/*
+ * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
+ *
+ * Returns: - 0 if the scb was pinned.
+ *          - > 0 if control has to be given to guest 2
+ *          - -ENOMEM if out of memory
+ */
+static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
+		   gpa_t gpa)
+{
+	hpa_t hpa;
+	int rc;
+
+	rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
+	if (rc == -EINVAL) {
+		rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+		if (!rc)
+			rc = 1;
+	}
+	if (!rc)
+		vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
+	return rc;
+}
+
+/*
+ * Inject a fault into guest 2.
+ *
+ * Returns: - > 0 if control has to be given to guest 2
+ *            < 0 if an error occurred during injection.
+ */
+static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr,
+			bool write_flag)
+{
+	struct kvm_s390_pgm_info pgm = {
+		.code = code,
+		.trans_exc_code =
+			/* 0-51: virtual address */
+			(vaddr & 0xfffffffffffff000UL) |
+			/* 52-53: store / fetch */
+			(((unsigned int) !write_flag) + 1) << 10,
+			/* 62-63: asce id (alway primary == 0) */
+		.exc_access_id = 0, /* always primary */
+		.op_access_id = 0, /* not MVPG */
+	};
+	int rc;
+
+	if (code == PGM_PROTECTION)
+		pgm.trans_exc_code |= 0x4UL;
+
+	rc = kvm_s390_inject_prog_irq(vcpu, &pgm);
+	return rc ? rc : 1;
+}
+
+/*
+ * Handle a fault during vsie execution on a gmap shadow.
+ *
+ * Returns: - 0 if the fault was resolved
+ *          - > 0 if control has to be given to guest 2
+ *          - < 0 if an error occurred
+ */
+static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	int rc;
+
+	if (current->thread.gmap_int_code == PGM_PROTECTION)
+		/* we can directly forward all protection exceptions */
+		return inject_fault(vcpu, PGM_PROTECTION,
+				    current->thread.gmap_addr, 1);
+
+	rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
+				   current->thread.gmap_addr);
+	if (rc > 0) {
+		rc = inject_fault(vcpu, rc,
+				  current->thread.gmap_addr,
+				  current->thread.gmap_write_flag);
+		if (rc >= 0)
+			vsie_page->fault_addr = current->thread.gmap_addr;
+	}
+	return rc;
+}
+
+/*
+ * Retry the previous fault that required guest 2 intervention. This avoids
+ * one superfluous SIE re-entry and direct exit.
+ *
+ * Will ignore any errors. The next SIE fault will do proper fault handling.
+ */
+static void handle_last_fault(struct kvm_vcpu *vcpu,
+			      struct vsie_page *vsie_page)
+{
+	if (vsie_page->fault_addr)
+		kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
+				      vsie_page->fault_addr);
+	vsie_page->fault_addr = 0;
+}
+
+static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
+{
+	vsie_page->scb_s.icptcode = 0;
+}
+
+/* rewind the psw and clear the vsie icpt, so we can retry execution */
+static void retry_vsie_icpt(struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	int ilen = insn_length(scb_s->ipa >> 8);
+
+	/* take care of EXECUTE instructions */
+	if (scb_s->icptstatus & 1) {
+		ilen = (scb_s->icptstatus >> 4) & 0x6;
+		if (!ilen)
+			ilen = 4;
+	}
+	scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen);
+	clear_vsie_icpt(vsie_page);
+}
+
+/*
+ * Try to shadow + enable the guest 2 provided facility list.
+ * Retry instruction execution if enabled for and provided by guest 2.
+ *
+ * Returns: - 0 if handled (retry or guest 2 icpt)
+ *          - > 0 if control has to be given to guest 2
+ */
+static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	__u32 fac = vsie_page->scb_o->fac & 0x7ffffff8U;
+
+	if (fac && test_kvm_facility(vcpu->kvm, 7)) {
+		retry_vsie_icpt(vsie_page);
+		if (read_guest_real(vcpu, fac, &vsie_page->fac,
+				    sizeof(vsie_page->fac)))
+			return set_validity_icpt(scb_s, 0x1090U);
+		scb_s->fac = (__u32)(__u64) &vsie_page->fac;
+	}
+	return 0;
+}
+
+/*
+ * Run the vsie on a shadow scb and a shadow gmap, without any further
+ * sanity checks, handling SIE faults.
+ *
+ * Returns: - 0 everything went fine
+ *          - > 0 if control has to be given to guest 2
+ *          - < 0 if an error occurred
+ */
+static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	int rc;
+
+	handle_last_fault(vcpu, vsie_page);
+
+	if (need_resched())
+		schedule();
+	if (test_cpu_flag(CIF_MCCK_PENDING))
+		s390_handle_mcck();
+
+	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+	local_irq_disable();
+	guest_enter_irqoff();
+	local_irq_enable();
+
+	rc = sie64a(scb_s, vcpu->run->s.regs.gprs);
+
+	local_irq_disable();
+	guest_exit_irqoff();
+	local_irq_enable();
+	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+	if (rc > 0)
+		rc = 0; /* we could still have an icpt */
+	else if (rc == -EFAULT)
+		return handle_fault(vcpu, vsie_page);
+
+	switch (scb_s->icptcode) {
+	case ICPT_INST:
+		if (scb_s->ipa == 0xb2b0)
+			rc = handle_stfle(vcpu, vsie_page);
+		break;
+	case ICPT_STOP:
+		/* stop not requested by g2 - must have been a kick */
+		if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
+			clear_vsie_icpt(vsie_page);
+		break;
+	case ICPT_VALIDITY:
+		if ((scb_s->ipa & 0xf000) != 0xf000)
+			scb_s->ipa += 0x1000;
+		break;
+	}
+	return rc;
+}
+
+static void release_gmap_shadow(struct vsie_page *vsie_page)
+{
+	if (vsie_page->gmap)
+		gmap_put(vsie_page->gmap);
+	WRITE_ONCE(vsie_page->gmap, NULL);
+	prefix_unmapped(vsie_page);
+}
+
+static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
+			       struct vsie_page *vsie_page)
+{
+	unsigned long asce;
+	union ctlreg0 cr0;
+	struct gmap *gmap;
+	int edat;
+
+	asce = vcpu->arch.sie_block->gcr[1];
+	cr0.val = vcpu->arch.sie_block->gcr[0];
+	edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
+	edat += edat && test_kvm_facility(vcpu->kvm, 78);
+
+	/*
+	 * ASCE or EDAT could have changed since last icpt, or the gmap
+	 * we're holding has been unshadowed. If the gmap is still valid,
+	 * we can safely reuse it.
+	 */
+	if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat))
+		return 0;
+
+	/* release the old shadow - if any, and mark the prefix as unmapped */
+	release_gmap_shadow(vsie_page);
+	gmap = gmap_shadow(vcpu->arch.gmap, asce, edat);
+	if (IS_ERR(gmap))
+		return PTR_ERR(gmap);
+	gmap->private = vcpu->kvm;
+	WRITE_ONCE(vsie_page->gmap, gmap);
+	return 0;
+}
+
+/*
+ * Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
+ */
+static void register_shadow_scb(struct kvm_vcpu *vcpu,
+				struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+
+	WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
+	/*
+	 * External calls have to lead to a kick of the vcpu and
+	 * therefore the vsie -> Simulate Wait state.
+	 */
+	atomic_or(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
+	/*
+	 * We have to adjust the g3 epoch by the g2 epoch. The epoch will
+	 * automatically be adjusted on tod clock changes via kvm_sync_clock.
+	 */
+	preempt_disable();
+	scb_s->epoch += vcpu->kvm->arch.epoch;
+	preempt_enable();
+}
+
+/*
+ * Unregister a shadow scb from a VCPU.
+ */
+static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
+{
+	atomic_andnot(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
+	WRITE_ONCE(vcpu->arch.vsie_block, NULL);
+}
+
+/*
+ * Run the vsie on a shadowed scb, managing the gmap shadow, handling
+ * prefix pages and faults.
+ *
+ * Returns: - 0 if no errors occurred
+ *          - > 0 if control has to be given to guest 2
+ *          - -ENOMEM if out of memory
+ */
+static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+	int rc = 0;
+
+	while (1) {
+		rc = acquire_gmap_shadow(vcpu, vsie_page);
+		if (!rc)
+			rc = map_prefix(vcpu, vsie_page);
+		if (!rc) {
+			gmap_enable(vsie_page->gmap);
+			update_intervention_requests(vsie_page);
+			rc = do_vsie_run(vcpu, vsie_page);
+			gmap_enable(vcpu->arch.gmap);
+		}
+		atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
+
+		if (rc == -EAGAIN)
+			rc = 0;
+		if (rc || scb_s->icptcode || signal_pending(current) ||
+		    kvm_s390_vcpu_has_irq(vcpu, 0))
+			break;
+	};
+
+	if (rc == -EFAULT) {
+		/*
+		 * Addressing exceptions are always presentes as intercepts.
+		 * As addressing exceptions are suppressing and our guest 3 PSW
+		 * points at the responsible instruction, we have to
+		 * forward the PSW and set the ilc. If we can't read guest 3
+		 * instruction, we can use an arbitrary ilc. Let's always use
+		 * ilen = 4 for now, so we can avoid reading in guest 3 virtual
+		 * memory. (we could also fake the shadow so the hardware
+		 * handles it).
+		 */
+		scb_s->icptcode = ICPT_PROGI;
+		scb_s->iprcc = PGM_ADDRESSING;
+		scb_s->pgmilc = 4;
+		scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
+	}
+	return rc;
+}
+
+/*
+ * Get or create a vsie page for a scb address.
+ *
+ * Returns: - address of a vsie page (cached or new one)
+ *          - NULL if the same scb address is already used by another VCPU
+ *          - ERR_PTR(-ENOMEM) if out of memory
+ */
+static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
+{
+	struct vsie_page *vsie_page;
+	struct page *page;
+	int nr_vcpus;
+
+	rcu_read_lock();
+	page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
+	rcu_read_unlock();
+	if (page) {
+		if (page_ref_inc_return(page) == 2)
+			return page_to_virt(page);
+		page_ref_dec(page);
+	}
+
+	/*
+	 * We want at least #online_vcpus shadows, so every VCPU can execute
+	 * the VSIE in parallel.
+	 */
+	nr_vcpus = atomic_read(&kvm->online_vcpus);
+
+	mutex_lock(&kvm->arch.vsie.mutex);
+	if (kvm->arch.vsie.page_count < nr_vcpus) {
+		page = alloc_page(GFP_KERNEL | __GFP_ZERO | GFP_DMA);
+		if (!page) {
+			mutex_unlock(&kvm->arch.vsie.mutex);
+			return ERR_PTR(-ENOMEM);
+		}
+		page_ref_inc(page);
+		kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
+		kvm->arch.vsie.page_count++;
+	} else {
+		/* reuse an existing entry that belongs to nobody */
+		while (true) {
+			page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
+			if (page_ref_inc_return(page) == 2)
+				break;
+			page_ref_dec(page);
+			kvm->arch.vsie.next++;
+			kvm->arch.vsie.next %= nr_vcpus;
+		}
+		radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
+	}
+	page->index = addr;
+	/* double use of the same address */
+	if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
+		page_ref_dec(page);
+		mutex_unlock(&kvm->arch.vsie.mutex);
+		return NULL;
+	}
+	mutex_unlock(&kvm->arch.vsie.mutex);
+
+	vsie_page = page_to_virt(page);
+	memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
+	release_gmap_shadow(vsie_page);
+	vsie_page->fault_addr = 0;
+	vsie_page->scb_s.ihcpu = 0xffffU;
+	return vsie_page;
+}
+
+/* put a vsie page acquired via get_vsie_page */
+static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page)
+{
+	struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT);
+
+	page_ref_dec(page);
+}
+
+int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
+{
+	struct vsie_page *vsie_page;
+	unsigned long scb_addr;
+	int rc;
+
+	vcpu->stat.instruction_sie++;
+	if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2))
+		return -EOPNOTSUPP;
+	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
+		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
+
+	BUILD_BUG_ON(sizeof(struct vsie_page) != 4096);
+	scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL);
+
+	/* 512 byte alignment */
+	if (unlikely(scb_addr & 0x1ffUL))
+		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+
+	if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0))
+		return 0;
+
+	vsie_page = get_vsie_page(vcpu->kvm, scb_addr);
+	if (IS_ERR(vsie_page))
+		return PTR_ERR(vsie_page);
+	else if (!vsie_page)
+		/* double use of sie control block - simply do nothing */
+		return 0;
+
+	rc = pin_scb(vcpu, vsie_page, scb_addr);
+	if (rc)
+		goto out_put;
+	rc = shadow_scb(vcpu, vsie_page);
+	if (rc)
+		goto out_unpin_scb;
+	rc = pin_blocks(vcpu, vsie_page);
+	if (rc)
+		goto out_unshadow;
+	register_shadow_scb(vcpu, vsie_page);
+	rc = vsie_run(vcpu, vsie_page);
+	unregister_shadow_scb(vcpu);
+	unpin_blocks(vcpu, vsie_page);
+out_unshadow:
+	unshadow_scb(vcpu, vsie_page);
+out_unpin_scb:
+	unpin_scb(vcpu, vsie_page, scb_addr);
+out_put:
+	put_vsie_page(vcpu->kvm, vsie_page);
+
+	return rc < 0 ? rc : 0;
+}
+
+/* Init the vsie data structures. To be called when a vm is initialized. */
+void kvm_s390_vsie_init(struct kvm *kvm)
+{
+	mutex_init(&kvm->arch.vsie.mutex);
+	INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL);
+}
+
+/* Destroy the vsie data structures. To be called when a vm is destroyed. */
+void kvm_s390_vsie_destroy(struct kvm *kvm)
+{
+	struct vsie_page *vsie_page;
+	struct page *page;
+	int i;
+
+	mutex_lock(&kvm->arch.vsie.mutex);
+	for (i = 0; i < kvm->arch.vsie.page_count; i++) {
+		page = kvm->arch.vsie.pages[i];
+		kvm->arch.vsie.pages[i] = NULL;
+		vsie_page = page_to_virt(page);
+		release_gmap_shadow(vsie_page);
+		/* free the radix tree entry */
+		radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
+		__free_page(page);
+	}
+	kvm->arch.vsie.page_count = 0;
+	mutex_unlock(&kvm->arch.vsie.mutex);
+}
+
+void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
+{
+	struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
+
+	/*
+	 * Even if the VCPU lets go of the shadow sie block reference, it is
+	 * still valid in the cache. So we can safely kick it.
+	 */
+	if (scb) {
+		atomic_or(PROG_BLOCK_SIE, &scb->prog20);
+		if (scb->prog0c & PROG_IN_SIE)
+			atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
+	}
+}