Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1204 insertions, 0 deletions

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
new file mode 100644
index 000000000..07d30ffcf
--- /dev/null
+++ b/arch/s390/kvm/gaccess.c
@@ -0,0 +1,1204 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * guest access functions
+ *
+ * Copyright IBM Corp. 2014
+ *
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/mm_types.h>
+#include <linux/err.h>
+
+#include <asm/pgtable.h>
+#include <asm/gmap.h>
+#include "kvm-s390.h"
+#include "gaccess.h"
+#include <asm/switch_to.h>
+
+union asce {
+	unsigned long val;
+	struct {
+		unsigned long origin : 52; /* Region- or Segment-Table Origin */
+		unsigned long	 : 2;
+		unsigned long g  : 1; /* Subspace Group Control */
+		unsigned long p  : 1; /* Private Space Control */
+		unsigned long s  : 1; /* Storage-Alteration-Event Control */
+		unsigned long x  : 1; /* Space-Switch-Event Control */
+		unsigned long r  : 1; /* Real-Space Control */
+		unsigned long	 : 1;
+		unsigned long dt : 2; /* Designation-Type Control */
+		unsigned long tl : 2; /* Region- or Segment-Table Length */
+	};
+};
+
+enum {
+	ASCE_TYPE_SEGMENT = 0,
+	ASCE_TYPE_REGION3 = 1,
+	ASCE_TYPE_REGION2 = 2,
+	ASCE_TYPE_REGION1 = 3
+};
+
+union region1_table_entry {
+	unsigned long val;
+	struct {
+		unsigned long rto: 52;/* Region-Table Origin */
+		unsigned long	 : 2;
+		unsigned long p  : 1; /* DAT-Protection Bit */
+		unsigned long	 : 1;
+		unsigned long tf : 2; /* Region-Second-Table Offset */
+		unsigned long i  : 1; /* Region-Invalid Bit */
+		unsigned long	 : 1;
+		unsigned long tt : 2; /* Table-Type Bits */
+		unsigned long tl : 2; /* Region-Second-Table Length */
+	};
+};
+
+union region2_table_entry {
+	unsigned long val;
+	struct {
+		unsigned long rto: 52;/* Region-Table Origin */
+		unsigned long	 : 2;
+		unsigned long p  : 1; /* DAT-Protection Bit */
+		unsigned long	 : 1;
+		unsigned long tf : 2; /* Region-Third-Table Offset */
+		unsigned long i  : 1; /* Region-Invalid Bit */
+		unsigned long	 : 1;
+		unsigned long tt : 2; /* Table-Type Bits */
+		unsigned long tl : 2; /* Region-Third-Table Length */
+	};
+};
+
+struct region3_table_entry_fc0 {
+	unsigned long sto: 52;/* Segment-Table Origin */
+	unsigned long	 : 1;
+	unsigned long fc : 1; /* Format-Control */
+	unsigned long p  : 1; /* DAT-Protection Bit */
+	unsigned long	 : 1;
+	unsigned long tf : 2; /* Segment-Table Offset */
+	unsigned long i  : 1; /* Region-Invalid Bit */
+	unsigned long cr : 1; /* Common-Region Bit */
+	unsigned long tt : 2; /* Table-Type Bits */
+	unsigned long tl : 2; /* Segment-Table Length */
+};
+
+struct region3_table_entry_fc1 {
+	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
+	unsigned long	 : 14;
+	unsigned long av : 1; /* ACCF-Validity Control */
+	unsigned long acc: 4; /* Access-Control Bits */
+	unsigned long f  : 1; /* Fetch-Protection Bit */
+	unsigned long fc : 1; /* Format-Control */
+	unsigned long p  : 1; /* DAT-Protection Bit */
+	unsigned long iep: 1; /* Instruction-Execution-Protection */
+	unsigned long	 : 2;
+	unsigned long i  : 1; /* Region-Invalid Bit */
+	unsigned long cr : 1; /* Common-Region Bit */
+	unsigned long tt : 2; /* Table-Type Bits */
+	unsigned long	 : 2;
+};
+
+union region3_table_entry {
+	unsigned long val;
+	struct region3_table_entry_fc0 fc0;
+	struct region3_table_entry_fc1 fc1;
+	struct {
+		unsigned long	 : 53;
+		unsigned long fc : 1; /* Format-Control */
+		unsigned long	 : 4;
+		unsigned long i  : 1; /* Region-Invalid Bit */
+		unsigned long cr : 1; /* Common-Region Bit */
+		unsigned long tt : 2; /* Table-Type Bits */
+		unsigned long	 : 2;
+	};
+};
+
+struct segment_entry_fc0 {
+	unsigned long pto: 53;/* Page-Table Origin */
+	unsigned long fc : 1; /* Format-Control */
+	unsigned long p  : 1; /* DAT-Protection Bit */
+	unsigned long	 : 3;
+	unsigned long i  : 1; /* Segment-Invalid Bit */
+	unsigned long cs : 1; /* Common-Segment Bit */
+	unsigned long tt : 2; /* Table-Type Bits */
+	unsigned long	 : 2;
+};
+
+struct segment_entry_fc1 {
+	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
+	unsigned long	 : 3;
+	unsigned long av : 1; /* ACCF-Validity Control */
+	unsigned long acc: 4; /* Access-Control Bits */
+	unsigned long f  : 1; /* Fetch-Protection Bit */
+	unsigned long fc : 1; /* Format-Control */
+	unsigned long p  : 1; /* DAT-Protection Bit */
+	unsigned long iep: 1; /* Instruction-Execution-Protection */
+	unsigned long	 : 2;
+	unsigned long i  : 1; /* Segment-Invalid Bit */
+	unsigned long cs : 1; /* Common-Segment Bit */
+	unsigned long tt : 2; /* Table-Type Bits */
+	unsigned long	 : 2;
+};
+
+union segment_table_entry {
+	unsigned long val;
+	struct segment_entry_fc0 fc0;
+	struct segment_entry_fc1 fc1;
+	struct {
+		unsigned long	 : 53;
+		unsigned long fc : 1; /* Format-Control */
+		unsigned long	 : 4;
+		unsigned long i  : 1; /* Segment-Invalid Bit */
+		unsigned long cs : 1; /* Common-Segment Bit */
+		unsigned long tt : 2; /* Table-Type Bits */
+		unsigned long	 : 2;
+	};
+};
+
+enum {
+	TABLE_TYPE_SEGMENT = 0,
+	TABLE_TYPE_REGION3 = 1,
+	TABLE_TYPE_REGION2 = 2,
+	TABLE_TYPE_REGION1 = 3
+};
+
+union page_table_entry {
+	unsigned long val;
+	struct {
+		unsigned long pfra : 52; /* Page-Frame Real Address */
+		unsigned long z  : 1; /* Zero Bit */
+		unsigned long i  : 1; /* Page-Invalid Bit */
+		unsigned long p  : 1; /* DAT-Protection Bit */
+		unsigned long iep: 1; /* Instruction-Execution-Protection */
+		unsigned long	 : 8;
+	};
+};
+
+/*
+ * vaddress union in order to easily decode a virtual address into its
+ * region first index, region second index etc. parts.
+ */
+union vaddress {
+	unsigned long addr;
+	struct {
+		unsigned long rfx : 11;
+		unsigned long rsx : 11;
+		unsigned long rtx : 11;
+		unsigned long sx  : 11;
+		unsigned long px  : 8;
+		unsigned long bx  : 12;
+	};
+	struct {
+		unsigned long rfx01 : 2;
+		unsigned long	    : 9;
+		unsigned long rsx01 : 2;
+		unsigned long	    : 9;
+		unsigned long rtx01 : 2;
+		unsigned long	    : 9;
+		unsigned long sx01  : 2;
+		unsigned long	    : 29;
+	};
+};
+
+/*
+ * raddress union which will contain the result (real or absolute address)
+ * after a page table walk. The rfaa, sfaa and pfra members are used to
+ * simply assign them the value of a region, segment or page table entry.
+ */
+union raddress {
+	unsigned long addr;
+	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
+	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
+	unsigned long pfra : 52; /* Page-Frame Real Address */
+};
+
+union alet {
+	u32 val;
+	struct {
+		u32 reserved : 7;
+		u32 p        : 1;
+		u32 alesn    : 8;
+		u32 alen     : 16;
+	};
+};
+
+union ald {
+	u32 val;
+	struct {
+		u32     : 1;
+		u32 alo : 24;
+		u32 all : 7;
+	};
+};
+
+struct ale {
+	unsigned long i      : 1; /* ALEN-Invalid Bit */
+	unsigned long        : 5;
+	unsigned long fo     : 1; /* Fetch-Only Bit */
+	unsigned long p      : 1; /* Private Bit */
+	unsigned long alesn  : 8; /* Access-List-Entry Sequence Number */
+	unsigned long aleax  : 16; /* Access-List-Entry Authorization Index */
+	unsigned long        : 32;
+	unsigned long        : 1;
+	unsigned long asteo  : 25; /* ASN-Second-Table-Entry Origin */
+	unsigned long        : 6;
+	unsigned long astesn : 32; /* ASTE Sequence Number */
+};
+
+struct aste {
+	unsigned long i      : 1; /* ASX-Invalid Bit */
+	unsigned long ato    : 29; /* Authority-Table Origin */
+	unsigned long        : 1;
+	unsigned long b      : 1; /* Base-Space Bit */
+	unsigned long ax     : 16; /* Authorization Index */
+	unsigned long atl    : 12; /* Authority-Table Length */
+	unsigned long        : 2;
+	unsigned long ca     : 1; /* Controlled-ASN Bit */
+	unsigned long ra     : 1; /* Reusable-ASN Bit */
+	unsigned long asce   : 64; /* Address-Space-Control Element */
+	unsigned long ald    : 32;
+	unsigned long astesn : 32;
+	/* .. more fields there */
+};
+
+int ipte_lock_held(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.sie_block->eca & ECA_SII) {
+		int rc;
+
+		read_lock(&vcpu->kvm->arch.sca_lock);
+		rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0;
+		read_unlock(&vcpu->kvm->arch.sca_lock);
+		return rc;
+	}
+	return vcpu->kvm->arch.ipte_lock_count != 0;
+}
+
+static void ipte_lock_simple(struct kvm_vcpu *vcpu)
+{
+	union ipte_control old, new, *ic;
+
+	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
+	vcpu->kvm->arch.ipte_lock_count++;
+	if (vcpu->kvm->arch.ipte_lock_count > 1)
+		goto out;
+retry:
+	read_lock(&vcpu->kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	do {
+		old = READ_ONCE(*ic);
+		if (old.k) {
+			read_unlock(&vcpu->kvm->arch.sca_lock);
+			cond_resched();
+			goto retry;
+		}
+		new = old;
+		new.k = 1;
+	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+	read_unlock(&vcpu->kvm->arch.sca_lock);
+out:
+	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+}
+
+static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
+{
+	union ipte_control old, new, *ic;
+
+	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
+	vcpu->kvm->arch.ipte_lock_count--;
+	if (vcpu->kvm->arch.ipte_lock_count)
+		goto out;
+	read_lock(&vcpu->kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	do {
+		old = READ_ONCE(*ic);
+		new = old;
+		new.k = 0;
+	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+	read_unlock(&vcpu->kvm->arch.sca_lock);
+	wake_up(&vcpu->kvm->arch.ipte_wq);
+out:
+	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+}
+
+static void ipte_lock_siif(struct kvm_vcpu *vcpu)
+{
+	union ipte_control old, new, *ic;
+
+retry:
+	read_lock(&vcpu->kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	do {
+		old = READ_ONCE(*ic);
+		if (old.kg) {
+			read_unlock(&vcpu->kvm->arch.sca_lock);
+			cond_resched();
+			goto retry;
+		}
+		new = old;
+		new.k = 1;
+		new.kh++;
+	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+	read_unlock(&vcpu->kvm->arch.sca_lock);
+}
+
+static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
+{
+	union ipte_control old, new, *ic;
+
+	read_lock(&vcpu->kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	do {
+		old = READ_ONCE(*ic);
+		new = old;
+		new.kh--;
+		if (!new.kh)
+			new.k = 0;
+	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+	read_unlock(&vcpu->kvm->arch.sca_lock);
+	if (!new.kh)
+		wake_up(&vcpu->kvm->arch.ipte_wq);
+}
+
+void ipte_lock(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.sie_block->eca & ECA_SII)
+		ipte_lock_siif(vcpu);
+	else
+		ipte_lock_simple(vcpu);
+}
+
+void ipte_unlock(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.sie_block->eca & ECA_SII)
+		ipte_unlock_siif(vcpu);
+	else
+		ipte_unlock_simple(vcpu);
+}
+
+static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
+			  enum gacc_mode mode)
+{
+	union alet alet;
+	struct ale ale;
+	struct aste aste;
+	unsigned long ald_addr, authority_table_addr;
+	union ald ald;
+	int eax, rc;
+	u8 authority_table;
+
+	if (ar >= NUM_ACRS)
+		return -EINVAL;
+
+	save_access_regs(vcpu->run->s.regs.acrs);
+	alet.val = vcpu->run->s.regs.acrs[ar];
+
+	if (ar == 0 || alet.val == 0) {
+		asce->val = vcpu->arch.sie_block->gcr[1];
+		return 0;
+	} else if (alet.val == 1) {
+		asce->val = vcpu->arch.sie_block->gcr[7];
+		return 0;
+	}
+
+	if (alet.reserved)
+		return PGM_ALET_SPECIFICATION;
+
+	if (alet.p)
+		ald_addr = vcpu->arch.sie_block->gcr[5];
+	else
+		ald_addr = vcpu->arch.sie_block->gcr[2];
+	ald_addr &= 0x7fffffc0;
+
+	rc = read_guest_real(vcpu, ald_addr + 16, &ald.val, sizeof(union ald));
+	if (rc)
+		return rc;
+
+	if (alet.alen / 8 > ald.all)
+		return PGM_ALEN_TRANSLATION;
+
+	if (0x7fffffff - ald.alo * 128 < alet.alen * 16)
+		return PGM_ADDRESSING;
+
+	rc = read_guest_real(vcpu, ald.alo * 128 + alet.alen * 16, &ale,
+			     sizeof(struct ale));
+	if (rc)
+		return rc;
+
+	if (ale.i == 1)
+		return PGM_ALEN_TRANSLATION;
+	if (ale.alesn != alet.alesn)
+		return PGM_ALE_SEQUENCE;
+
+	rc = read_guest_real(vcpu, ale.asteo * 64, &aste, sizeof(struct aste));
+	if (rc)
+		return rc;
+
+	if (aste.i)
+		return PGM_ASTE_VALIDITY;
+	if (aste.astesn != ale.astesn)
+		return PGM_ASTE_SEQUENCE;
+
+	if (ale.p == 1) {
+		eax = (vcpu->arch.sie_block->gcr[8] >> 16) & 0xffff;
+		if (ale.aleax != eax) {
+			if (eax / 16 > aste.atl)
+				return PGM_EXTENDED_AUTHORITY;
+
+			authority_table_addr = aste.ato * 4 + eax / 4;
+
+			rc = read_guest_real(vcpu, authority_table_addr,
+					     &authority_table,
+					     sizeof(u8));
+			if (rc)
+				return rc;
+
+			if ((authority_table & (0x40 >> ((eax & 3) * 2))) == 0)
+				return PGM_EXTENDED_AUTHORITY;
+		}
+	}
+
+	if (ale.fo == 1 && mode == GACC_STORE)
+		return PGM_PROTECTION;
+
+	asce->val = aste.asce;
+	return 0;
+}
+
+struct trans_exc_code_bits {
+	unsigned long addr : 52; /* Translation-exception Address */
+	unsigned long fsi  : 2;  /* Access Exception Fetch/Store Indication */
+	unsigned long	   : 2;
+	unsigned long b56  : 1;
+	unsigned long	   : 3;
+	unsigned long b60  : 1;
+	unsigned long b61  : 1;
+	unsigned long as   : 2;  /* ASCE Identifier */
+};
+
+enum {
+	FSI_UNKNOWN = 0, /* Unknown wether fetch or store */
+	FSI_STORE   = 1, /* Exception was due to store operation */
+	FSI_FETCH   = 2  /* Exception was due to fetch operation */
+};
+
+enum prot_type {
+	PROT_TYPE_LA   = 0,
+	PROT_TYPE_KEYC = 1,
+	PROT_TYPE_ALC  = 2,
+	PROT_TYPE_DAT  = 3,
+	PROT_TYPE_IEP  = 4,
+};
+
+static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva,
+		     u8 ar, enum gacc_mode mode, enum prot_type prot)
+{
+	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
+	struct trans_exc_code_bits *tec;
+
+	memset(pgm, 0, sizeof(*pgm));
+	pgm->code = code;
+	tec = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
+
+	switch (code) {
+	case PGM_PROTECTION:
+		switch (prot) {
+		case PROT_TYPE_IEP:
+			tec->b61 = 1;
+			/* FALL THROUGH */
+		case PROT_TYPE_LA:
+			tec->b56 = 1;
+			break;
+		case PROT_TYPE_KEYC:
+			tec->b60 = 1;
+			break;
+		case PROT_TYPE_ALC:
+			tec->b60 = 1;
+			/* FALL THROUGH */
+		case PROT_TYPE_DAT:
+			tec->b61 = 1;
+			break;
+		}
+		/* FALL THROUGH */
+	case PGM_ASCE_TYPE:
+	case PGM_PAGE_TRANSLATION:
+	case PGM_REGION_FIRST_TRANS:
+	case PGM_REGION_SECOND_TRANS:
+	case PGM_REGION_THIRD_TRANS:
+	case PGM_SEGMENT_TRANSLATION:
+		/*
+		 * op_access_id only applies to MOVE_PAGE -> set bit 61
+		 * exc_access_id has to be set to 0 for some instructions. Both
+		 * cases have to be handled by the caller.
+		 */
+		tec->addr = gva >> PAGE_SHIFT;
+		tec->fsi = mode == GACC_STORE ? FSI_STORE : FSI_FETCH;
+		tec->as = psw_bits(vcpu->arch.sie_block->gpsw).as;
+		/* FALL THROUGH */
+	case PGM_ALEN_TRANSLATION:
+	case PGM_ALE_SEQUENCE:
+	case PGM_ASTE_VALIDITY:
+	case PGM_ASTE_SEQUENCE:
+	case PGM_EXTENDED_AUTHORITY:
+		/*
+		 * We can always store exc_access_id, as it is
+		 * undefined for non-ar cases. It is undefined for
+		 * most DAT protection exceptions.
+		 */
+		pgm->exc_access_id = ar;
+		break;
+	}
+	return code;
+}
+
+static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce,
+			 unsigned long ga, u8 ar, enum gacc_mode mode)
+{
+	int rc;
+	struct psw_bits psw = psw_bits(vcpu->arch.sie_block->gpsw);
+
+	if (!psw.dat) {
+		asce->val = 0;
+		asce->r = 1;
+		return 0;
+	}
+
+	if ((mode == GACC_IFETCH) && (psw.as != PSW_BITS_AS_HOME))
+		psw.as = PSW_BITS_AS_PRIMARY;
+
+	switch (psw.as) {
+	case PSW_BITS_AS_PRIMARY:
+		asce->val = vcpu->arch.sie_block->gcr[1];
+		return 0;
+	case PSW_BITS_AS_SECONDARY:
+		asce->val = vcpu->arch.sie_block->gcr[7];
+		return 0;
+	case PSW_BITS_AS_HOME:
+		asce->val = vcpu->arch.sie_block->gcr[13];
+		return 0;
+	case PSW_BITS_AS_ACCREG:
+		rc = ar_translation(vcpu, asce, ar, mode);
+		if (rc > 0)
+			return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_ALC);
+		return rc;
+	}
+	return 0;
+}
+
+static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val)
+{
+	return kvm_read_guest(kvm, gpa, val, sizeof(*val));
+}
+
+/**
+ * guest_translate - translate a guest virtual into a guest absolute address
+ * @vcpu: virtual cpu
+ * @gva: guest virtual address
+ * @gpa: points to where guest physical (absolute) address should be stored
+ * @asce: effective asce
+ * @mode: indicates the access mode to be used
+ * @prot: returns the type for protection exceptions
+ *
+ * Translate a guest virtual address into a guest absolute address by means
+ * of dynamic address translation as specified by the architecture.
+ * If the resulting absolute address is not available in the configuration
+ * an addressing exception is indicated and @gpa will not be changed.
+ *
+ * Returns: - zero on success; @gpa contains the resulting absolute address
+ *	    - a negative value if guest access failed due to e.g. broken
+ *	      guest mapping
+ *	    - a positve value if an access exception happened. In this case
+ *	      the returned value is the program interruption code as defined
+ *	      by the architecture
+ */
+static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
+				     unsigned long *gpa, const union asce asce,
+				     enum gacc_mode mode, enum prot_type *prot)
+{
+	union vaddress vaddr = {.addr = gva};
+	union raddress raddr = {.addr = gva};
+	union page_table_entry pte;
+	int dat_protection = 0;
+	int iep_protection = 0;
+	union ctlreg0 ctlreg0;
+	unsigned long ptr;
+	int edat1, edat2, iep;
+
+	ctlreg0.val = vcpu->arch.sie_block->gcr[0];
+	edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8);
+	edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78);
+	iep = ctlreg0.iep && test_kvm_facility(vcpu->kvm, 130);
+	if (asce.r)
+		goto real_address;
+	ptr = asce.origin * PAGE_SIZE;
+	switch (asce.dt) {
+	case ASCE_TYPE_REGION1:
+		if (vaddr.rfx01 > asce.tl)
+			return PGM_REGION_FIRST_TRANS;
+		ptr += vaddr.rfx * 8;
+		break;
+	case ASCE_TYPE_REGION2:
+		if (vaddr.rfx)
+			return PGM_ASCE_TYPE;
+		if (vaddr.rsx01 > asce.tl)
+			return PGM_REGION_SECOND_TRANS;
+		ptr += vaddr.rsx * 8;
+		break;
+	case ASCE_TYPE_REGION3:
+		if (vaddr.rfx || vaddr.rsx)
+			return PGM_ASCE_TYPE;
+		if (vaddr.rtx01 > asce.tl)
+			return PGM_REGION_THIRD_TRANS;
+		ptr += vaddr.rtx * 8;
+		break;
+	case ASCE_TYPE_SEGMENT:
+		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
+			return PGM_ASCE_TYPE;
+		if (vaddr.sx01 > asce.tl)
+			return PGM_SEGMENT_TRANSLATION;
+		ptr += vaddr.sx * 8;
+		break;
+	}
+	switch (asce.dt) {
+	case ASCE_TYPE_REGION1:	{
+		union region1_table_entry rfte;
+
+		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+			return PGM_ADDRESSING;
+		if (deref_table(vcpu->kvm, ptr, &rfte.val))
+			return -EFAULT;
+		if (rfte.i)
+			return PGM_REGION_FIRST_TRANS;
+		if (rfte.tt != TABLE_TYPE_REGION1)
+			return PGM_TRANSLATION_SPEC;
+		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
+			return PGM_REGION_SECOND_TRANS;
+		if (edat1)
+			dat_protection |= rfte.p;
+		ptr = rfte.rto * PAGE_SIZE + vaddr.rsx * 8;
+	}
+		/* fallthrough */
+	case ASCE_TYPE_REGION2: {
+		union region2_table_entry rste;
+
+		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+			return PGM_ADDRESSING;
+		if (deref_table(vcpu->kvm, ptr, &rste.val))
+			return -EFAULT;
+		if (rste.i)
+			return PGM_REGION_SECOND_TRANS;
+		if (rste.tt != TABLE_TYPE_REGION2)
+			return PGM_TRANSLATION_SPEC;
+		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
+			return PGM_REGION_THIRD_TRANS;
+		if (edat1)
+			dat_protection |= rste.p;
+		ptr = rste.rto * PAGE_SIZE + vaddr.rtx * 8;
+	}
+		/* fallthrough */
+	case ASCE_TYPE_REGION3: {
+		union region3_table_entry rtte;
+
+		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+			return PGM_ADDRESSING;
+		if (deref_table(vcpu->kvm, ptr, &rtte.val))
+			return -EFAULT;
+		if (rtte.i)
+			return PGM_REGION_THIRD_TRANS;
+		if (rtte.tt != TABLE_TYPE_REGION3)
+			return PGM_TRANSLATION_SPEC;
+		if (rtte.cr && asce.p && edat2)
+			return PGM_TRANSLATION_SPEC;
+		if (rtte.fc && edat2) {
+			dat_protection |= rtte.fc1.p;
+			iep_protection = rtte.fc1.iep;
+			raddr.rfaa = rtte.fc1.rfaa;
+			goto absolute_address;
+		}
+		if (vaddr.sx01 < rtte.fc0.tf)
+			return PGM_SEGMENT_TRANSLATION;
+		if (vaddr.sx01 > rtte.fc0.tl)
+			return PGM_SEGMENT_TRANSLATION;
+		if (edat1)
+			dat_protection |= rtte.fc0.p;
+		ptr = rtte.fc0.sto * PAGE_SIZE + vaddr.sx * 8;
+	}
+		/* fallthrough */
+	case ASCE_TYPE_SEGMENT: {
+		union segment_table_entry ste;
+
+		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+			return PGM_ADDRESSING;
+		if (deref_table(vcpu->kvm, ptr, &ste.val))
+			return -EFAULT;
+		if (ste.i)
+			return PGM_SEGMENT_TRANSLATION;
+		if (ste.tt != TABLE_TYPE_SEGMENT)
+			return PGM_TRANSLATION_SPEC;
+		if (ste.cs && asce.p)
+			return PGM_TRANSLATION_SPEC;
+		if (ste.fc && edat1) {
+			dat_protection |= ste.fc1.p;
+			iep_protection = ste.fc1.iep;
+			raddr.sfaa = ste.fc1.sfaa;
+			goto absolute_address;
+		}
+		dat_protection |= ste.fc0.p;
+		ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8;
+	}
+	}
+	if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		return PGM_ADDRESSING;
+	if (deref_table(vcpu->kvm, ptr, &pte.val))
+		return -EFAULT;
+	if (pte.i)
+		return PGM_PAGE_TRANSLATION;
+	if (pte.z)
+		return PGM_TRANSLATION_SPEC;
+	dat_protection |= pte.p;
+	iep_protection = pte.iep;
+	raddr.pfra = pte.pfra;
+real_address:
+	raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
+absolute_address:
+	if (mode == GACC_STORE && dat_protection) {
+		*prot = PROT_TYPE_DAT;
+		return PGM_PROTECTION;
+	}
+	if (mode == GACC_IFETCH && iep_protection && iep) {
+		*prot = PROT_TYPE_IEP;
+		return PGM_PROTECTION;
+	}
+	if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
+		return PGM_ADDRESSING;
+	*gpa = raddr.addr;
+	return 0;
+}
+
+static inline int is_low_address(unsigned long ga)
+{
+	/* Check for address ranges 0..511 and 4096..4607 */
+	return (ga & ~0x11fful) == 0;
+}
+
+static int low_address_protection_enabled(struct kvm_vcpu *vcpu,
+					  const union asce asce)
+{
+	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
+	psw_t *psw = &vcpu->arch.sie_block->gpsw;
+
+	if (!ctlreg0.lap)
+		return 0;
+	if (psw_bits(*psw).dat && asce.p)
+		return 0;
+	return 1;
+}
+
+static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
+			    unsigned long *pages, unsigned long nr_pages,
+			    const union asce asce, enum gacc_mode mode)
+{
+	psw_t *psw = &vcpu->arch.sie_block->gpsw;
+	int lap_enabled, rc = 0;
+	enum prot_type prot;
+
+	lap_enabled = low_address_protection_enabled(vcpu, asce);
+	while (nr_pages) {
+		ga = kvm_s390_logical_to_effective(vcpu, ga);
+		if (mode == GACC_STORE && lap_enabled && is_low_address(ga))
+			return trans_exc(vcpu, PGM_PROTECTION, ga, ar, mode,
+					 PROT_TYPE_LA);
+		ga &= PAGE_MASK;
+		if (psw_bits(*psw).dat) {
+			rc = guest_translate(vcpu, ga, pages, asce, mode, &prot);
+			if (rc < 0)
+				return rc;
+		} else {
+			*pages = kvm_s390_real_to_abs(vcpu, ga);
+			if (kvm_is_error_gpa(vcpu->kvm, *pages))
+				rc = PGM_ADDRESSING;
+		}
+		if (rc)
+			return trans_exc(vcpu, rc, ga, ar, mode, prot);
+		ga += PAGE_SIZE;
+		pages++;
+		nr_pages--;
+	}
+	return 0;
+}
+
+int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
+		 unsigned long len, enum gacc_mode mode)
+{
+	psw_t *psw = &vcpu->arch.sie_block->gpsw;
+	unsigned long _len, nr_pages, gpa, idx;
+	unsigned long pages_array[2];
+	unsigned long *pages;
+	int need_ipte_lock;
+	union asce asce;
+	int rc;
+
+	if (!len)
+		return 0;
+	ga = kvm_s390_logical_to_effective(vcpu, ga);
+	rc = get_vcpu_asce(vcpu, &asce, ga, ar, mode);
+	if (rc)
+		return rc;
+	nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1;
+	pages = pages_array;
+	if (nr_pages > ARRAY_SIZE(pages_array))
+		pages = vmalloc(array_size(nr_pages, sizeof(unsigned long)));
+	if (!pages)
+		return -ENOMEM;
+	need_ipte_lock = psw_bits(*psw).dat && !asce.r;
+	if (need_ipte_lock)
+		ipte_lock(vcpu);
+	rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode);
+	for (idx = 0; idx < nr_pages && !rc; idx++) {
+		gpa = *(pages + idx) + (ga & ~PAGE_MASK);
+		_len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
+		if (mode == GACC_STORE)
+			rc = kvm_write_guest(vcpu->kvm, gpa, data, _len);
+		else
+			rc = kvm_read_guest(vcpu->kvm, gpa, data, _len);
+		len -= _len;
+		ga += _len;
+		data += _len;
+	}
+	if (need_ipte_lock)
+		ipte_unlock(vcpu);
+	if (nr_pages > ARRAY_SIZE(pages_array))
+		vfree(pages);
+	return rc;
+}
+
+int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
+		      void *data, unsigned long len, enum gacc_mode mode)
+{
+	unsigned long _len, gpa;
+	int rc = 0;
+
+	while (len && !rc) {
+		gpa = kvm_s390_real_to_abs(vcpu, gra);
+		_len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
+		if (mode)
+			rc = write_guest_abs(vcpu, gpa, data, _len);
+		else
+			rc = read_guest_abs(vcpu, gpa, data, _len);
+		len -= _len;
+		gra += _len;
+		data += _len;
+	}
+	return rc;
+}
+
+/**
+ * guest_translate_address - translate guest logical into guest absolute address
+ *
+ * Parameter semantics are the same as the ones from guest_translate.
+ * The memory contents at the guest address are not changed.
+ *
+ * Note: The IPTE lock is not taken during this function, so the caller
+ * has to take care of this.
+ */
+int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
+			    unsigned long *gpa, enum gacc_mode mode)
+{
+	psw_t *psw = &vcpu->arch.sie_block->gpsw;
+	enum prot_type prot;
+	union asce asce;
+	int rc;
+
+	gva = kvm_s390_logical_to_effective(vcpu, gva);
+	rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
+	if (rc)
+		return rc;
+	if (is_low_address(gva) && low_address_protection_enabled(vcpu, asce)) {
+		if (mode == GACC_STORE)
+			return trans_exc(vcpu, PGM_PROTECTION, gva, 0,
+					 mode, PROT_TYPE_LA);
+	}
+
+	if (psw_bits(*psw).dat && !asce.r) {	/* Use DAT? */
+		rc = guest_translate(vcpu, gva, gpa, asce, mode, &prot);
+		if (rc > 0)
+			return trans_exc(vcpu, rc, gva, 0, mode, prot);
+	} else {
+		*gpa = kvm_s390_real_to_abs(vcpu, gva);
+		if (kvm_is_error_gpa(vcpu->kvm, *gpa))
+			return trans_exc(vcpu, rc, gva, PGM_ADDRESSING, mode, 0);
+	}
+
+	return rc;
+}
+
+/**
+ * check_gva_range - test a range of guest virtual addresses for accessibility
+ */
+int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
+		    unsigned long length, enum gacc_mode mode)
+{
+	unsigned long gpa;
+	unsigned long currlen;
+	int rc = 0;
+
+	ipte_lock(vcpu);
+	while (length > 0 && !rc) {
+		currlen = min(length, PAGE_SIZE - (gva % PAGE_SIZE));
+		rc = guest_translate_address(vcpu, gva, ar, &gpa, mode);
+		gva += currlen;
+		length -= currlen;
+	}
+	ipte_unlock(vcpu);
+
+	return rc;
+}
+
+/**
+ * kvm_s390_check_low_addr_prot_real - check for low-address protection
+ * @gra: Guest real address
+ *
+ * Checks whether an address is subject to low-address protection and set
+ * up vcpu->arch.pgm accordingly if necessary.
+ *
+ * Return: 0 if no protection exception, or PGM_PROTECTION if protected.
+ */
+int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra)
+{
+	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
+
+	if (!ctlreg0.lap || !is_low_address(gra))
+		return 0;
+	return trans_exc(vcpu, PGM_PROTECTION, gra, 0, GACC_STORE, PROT_TYPE_LA);
+}
+
+/**
+ * kvm_s390_shadow_tables - walk the guest page table and create shadow tables
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: faulting address in the shadow gmap
+ * @pgt: pointer to the page table address result
+ * @fake: pgt references contiguous guest memory block, not a pgtable
+ */
+static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
+				  unsigned long *pgt, int *dat_protection,
+				  int *fake)
+{
+	struct gmap *parent;
+	union asce asce;
+	union vaddress vaddr;
+	unsigned long ptr;
+	int rc;
+
+	*fake = 0;
+	*dat_protection = 0;
+	parent = sg->parent;
+	vaddr.addr = saddr;
+	asce.val = sg->orig_asce;
+	ptr = asce.origin * PAGE_SIZE;
+	if (asce.r) {
+		*fake = 1;
+		ptr = 0;
+		asce.dt = ASCE_TYPE_REGION1;
+	}
+	switch (asce.dt) {
+	case ASCE_TYPE_REGION1:
+		if (vaddr.rfx01 > asce.tl && !*fake)
+			return PGM_REGION_FIRST_TRANS;
+		break;
+	case ASCE_TYPE_REGION2:
+		if (vaddr.rfx)
+			return PGM_ASCE_TYPE;
+		if (vaddr.rsx01 > asce.tl)
+			return PGM_REGION_SECOND_TRANS;
+		break;
+	case ASCE_TYPE_REGION3:
+		if (vaddr.rfx || vaddr.rsx)
+			return PGM_ASCE_TYPE;
+		if (vaddr.rtx01 > asce.tl)
+			return PGM_REGION_THIRD_TRANS;
+		break;
+	case ASCE_TYPE_SEGMENT:
+		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
+			return PGM_ASCE_TYPE;
+		if (vaddr.sx01 > asce.tl)
+			return PGM_SEGMENT_TRANSLATION;
+		break;
+	}
+
+	switch (asce.dt) {
+	case ASCE_TYPE_REGION1: {
+		union region1_table_entry rfte;
+
+		if (*fake) {
+			ptr += vaddr.rfx * _REGION1_SIZE;
+			rfte.val = ptr;
+			goto shadow_r2t;
+		}
+		rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val);
+		if (rc)
+			return rc;
+		if (rfte.i)
+			return PGM_REGION_FIRST_TRANS;
+		if (rfte.tt != TABLE_TYPE_REGION1)
+			return PGM_TRANSLATION_SPEC;
+		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
+			return PGM_REGION_SECOND_TRANS;
+		if (sg->edat_level >= 1)
+			*dat_protection |= rfte.p;
+		ptr = rfte.rto * PAGE_SIZE;
+shadow_r2t:
+		rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake);
+		if (rc)
+			return rc;
+	} /* fallthrough */
+	case ASCE_TYPE_REGION2: {
+		union region2_table_entry rste;
+
+		if (*fake) {
+			ptr += vaddr.rsx * _REGION2_SIZE;
+			rste.val = ptr;
+			goto shadow_r3t;
+		}
+		rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val);
+		if (rc)
+			return rc;
+		if (rste.i)
+			return PGM_REGION_SECOND_TRANS;
+		if (rste.tt != TABLE_TYPE_REGION2)
+			return PGM_TRANSLATION_SPEC;
+		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
+			return PGM_REGION_THIRD_TRANS;
+		if (sg->edat_level >= 1)
+			*dat_protection |= rste.p;
+		ptr = rste.rto * PAGE_SIZE;
+shadow_r3t:
+		rste.p |= *dat_protection;
+		rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake);
+		if (rc)
+			return rc;
+	} /* fallthrough */
+	case ASCE_TYPE_REGION3: {
+		union region3_table_entry rtte;
+
+		if (*fake) {
+			ptr += vaddr.rtx * _REGION3_SIZE;
+			rtte.val = ptr;
+			goto shadow_sgt;
+		}
+		rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val);
+		if (rc)
+			return rc;
+		if (rtte.i)
+			return PGM_REGION_THIRD_TRANS;
+		if (rtte.tt != TABLE_TYPE_REGION3)
+			return PGM_TRANSLATION_SPEC;
+		if (rtte.cr && asce.p && sg->edat_level >= 2)
+			return PGM_TRANSLATION_SPEC;
+		if (rtte.fc && sg->edat_level >= 2) {
+			*dat_protection |= rtte.fc0.p;
+			*fake = 1;
+			ptr = rtte.fc1.rfaa * _REGION3_SIZE;
+			rtte.val = ptr;
+			goto shadow_sgt;
+		}
+		if (vaddr.sx01 < rtte.fc0.tf || vaddr.sx01 > rtte.fc0.tl)
+			return PGM_SEGMENT_TRANSLATION;
+		if (sg->edat_level >= 1)
+			*dat_protection |= rtte.fc0.p;
+		ptr = rtte.fc0.sto * PAGE_SIZE;
+shadow_sgt:
+		rtte.fc0.p |= *dat_protection;
+		rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake);
+		if (rc)
+			return rc;
+	} /* fallthrough */
+	case ASCE_TYPE_SEGMENT: {
+		union segment_table_entry ste;
+
+		if (*fake) {
+			ptr += vaddr.sx * _SEGMENT_SIZE;
+			ste.val = ptr;
+			goto shadow_pgt;
+		}
+		rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val);
+		if (rc)
+			return rc;
+		if (ste.i)
+			return PGM_SEGMENT_TRANSLATION;
+		if (ste.tt != TABLE_TYPE_SEGMENT)
+			return PGM_TRANSLATION_SPEC;
+		if (ste.cs && asce.p)
+			return PGM_TRANSLATION_SPEC;
+		*dat_protection |= ste.fc0.p;
+		if (ste.fc && sg->edat_level >= 1) {
+			*fake = 1;
+			ptr = ste.fc1.sfaa * _SEGMENT_SIZE;
+			ste.val = ptr;
+			goto shadow_pgt;
+		}
+		ptr = ste.fc0.pto * (PAGE_SIZE / 2);
+shadow_pgt:
+		ste.fc0.p |= *dat_protection;
+		rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake);
+		if (rc)
+			return rc;
+	}
+	}
+	/* Return the parent address of the page table */
+	*pgt = ptr;
+	return 0;
+}
+
+/**
+ * kvm_s390_shadow_fault - handle fault on a shadow page table
+ * @vcpu: virtual cpu
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: faulting address in the shadow gmap
+ *
+ * Returns: - 0 if the shadow fault was successfully resolved
+ *	    - > 0 (pgm exception code) on exceptions while faulting
+ *	    - -EAGAIN if the caller can retry immediately
+ *	    - -EFAULT when accessing invalid guest addresses
+ *	    - -ENOMEM if out of memory
+ */
+int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
+			  unsigned long saddr)
+{
+	union vaddress vaddr;
+	union page_table_entry pte;
+	unsigned long pgt;
+	int dat_protection, fake;
+	int rc;
+
+	down_read(&sg->mm->mmap_sem);
+	/*
+	 * We don't want any guest-2 tables to change - so the parent
+	 * tables/pointers we read stay valid - unshadowing is however
+	 * always possible - only guest_table_lock protects us.
+	 */
+	ipte_lock(vcpu);
+
+	rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
+	if (rc)
+		rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection,
+					    &fake);
+
+	vaddr.addr = saddr;
+	if (fake) {
+		pte.val = pgt + vaddr.px * PAGE_SIZE;
+		goto shadow_page;
+	}
+	if (!rc)
+		rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val);
+	if (!rc && pte.i)
+		rc = PGM_PAGE_TRANSLATION;
+	if (!rc && pte.z)
+		rc = PGM_TRANSLATION_SPEC;
+shadow_page:
+	pte.p |= dat_protection;
+	if (!rc)
+		rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
+	ipte_unlock(vcpu);
+	up_read(&sg->mm->mmap_sem);
+	return rc;
+}