1 files changed, 645 insertions, 344 deletions

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 07d30ffcfa41..21c2e61fece4 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -9,170 +9,16 @@
 #include <linux/vmalloc.h>
 #include <linux/mm_types.h>
 #include <linux/err.h>
-
-#include <asm/pgtable.h>
+#include <linux/pgtable.h>
+#include <linux/bitfield.h>
+#include <asm/access-regs.h>
+#include <asm/fault.h>
 #include <asm/gmap.h>
+#include <asm/dat-bits.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;
-	};
-};
+#define GMAP_SHADOW_FAKE_TABLE 1ULL
 
 /*
  * vaddress union in order to easily decode a virtual address into its
@@ -261,119 +107,119 @@ struct aste {
 	/* .. more fields there */
 };
 
-int ipte_lock_held(struct kvm_vcpu *vcpu)
+int ipte_lock_held(struct kvm *kvm)
 {
-	if (vcpu->arch.sie_block->eca & ECA_SII) {
+	if (sclp.has_siif) {
 		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);
+		read_lock(&kvm->arch.sca_lock);
+		rc = kvm_s390_get_ipte_control(kvm)->kh != 0;
+		read_unlock(&kvm->arch.sca_lock);
 		return rc;
 	}
-	return vcpu->kvm->arch.ipte_lock_count != 0;
+	return kvm->arch.ipte_lock_count != 0;
 }
 
-static void ipte_lock_simple(struct kvm_vcpu *vcpu)
+static void ipte_lock_simple(struct kvm *kvm)
 {
 	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)
+	mutex_lock(&kvm->arch.ipte_mutex);
+	kvm->arch.ipte_lock_count++;
+	if (kvm->arch.ipte_lock_count > 1)
 		goto out;
 retry:
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
+	old = READ_ONCE(*ic);
 	do {
-		old = READ_ONCE(*ic);
 		if (old.k) {
-			read_unlock(&vcpu->kvm->arch.sca_lock);
+			read_unlock(&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);
+	} while (!try_cmpxchg(&ic->val, &old.val, new.val));
+	read_unlock(&kvm->arch.sca_lock);
 out:
-	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+	mutex_unlock(&kvm->arch.ipte_mutex);
 }
 
-static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
+static void ipte_unlock_simple(struct kvm *kvm)
 {
 	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)
+	mutex_lock(&kvm->arch.ipte_mutex);
+	kvm->arch.ipte_lock_count--;
+	if (kvm->arch.ipte_lock_count)
 		goto out;
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
+	old = READ_ONCE(*ic);
 	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);
+	} while (!try_cmpxchg(&ic->val, &old.val, new.val));
+	read_unlock(&kvm->arch.sca_lock);
+	wake_up(&kvm->arch.ipte_wq);
 out:
-	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+	mutex_unlock(&kvm->arch.ipte_mutex);
 }
 
-static void ipte_lock_siif(struct kvm_vcpu *vcpu)
+static void ipte_lock_siif(struct kvm *kvm)
 {
 	union ipte_control old, new, *ic;
 
 retry:
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
+	old = READ_ONCE(*ic);
 	do {
-		old = READ_ONCE(*ic);
 		if (old.kg) {
-			read_unlock(&vcpu->kvm->arch.sca_lock);
+			read_unlock(&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);
+	} while (!try_cmpxchg(&ic->val, &old.val, new.val));
+	read_unlock(&kvm->arch.sca_lock);
 }
 
-static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
+static void ipte_unlock_siif(struct kvm *kvm)
 {
 	union ipte_control old, new, *ic;
 
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
+	old = READ_ONCE(*ic);
 	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);
+	} while (!try_cmpxchg(&ic->val, &old.val, new.val));
+	read_unlock(&kvm->arch.sca_lock);
 	if (!new.kh)
-		wake_up(&vcpu->kvm->arch.ipte_wq);
+		wake_up(&kvm->arch.ipte_wq);
 }
 
-void ipte_lock(struct kvm_vcpu *vcpu)
+void ipte_lock(struct kvm *kvm)
 {
-	if (vcpu->arch.sie_block->eca & ECA_SII)
-		ipte_lock_siif(vcpu);
+	if (sclp.has_siif)
+		ipte_lock_siif(kvm);
 	else
-		ipte_lock_simple(vcpu);
+		ipte_lock_simple(kvm);
 }
 
-void ipte_unlock(struct kvm_vcpu *vcpu)
+void ipte_unlock(struct kvm *kvm)
 {
-	if (vcpu->arch.sie_block->eca & ECA_SII)
-		ipte_unlock_siif(vcpu);
+	if (sclp.has_siif)
+		ipte_unlock_siif(kvm);
 	else
-		ipte_unlock_simple(vcpu);
+		ipte_unlock_simple(kvm);
 }
 
 static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
@@ -390,7 +236,8 @@ static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
 	if (ar >= NUM_ACRS)
 		return -EINVAL;
 
-	save_access_regs(vcpu->run->s.regs.acrs);
+	if (vcpu->arch.acrs_loaded)
+		save_access_regs(vcpu->run->s.regs.acrs);
 	alet.val = vcpu->run->s.regs.acrs[ar];
 
 	if (ar == 0 || alet.val == 0) {
@@ -465,61 +312,55 @@ static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
 	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,
+	/* Dummy value for passing an initialized value when code != PGM_PROTECTION */
+	PROT_TYPE_DUMMY,
 };
 
-static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva,
-		     u8 ar, enum gacc_mode mode, enum prot_type prot)
+static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar,
+			    enum gacc_mode mode, enum prot_type prot, bool terminate)
 {
 	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
-	struct trans_exc_code_bits *tec;
+	union teid *teid;
 
 	memset(pgm, 0, sizeof(*pgm));
 	pgm->code = code;
-	tec = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
+	teid = (union teid *)&pgm->trans_exc_code;
 
 	switch (code) {
 	case PGM_PROTECTION:
 		switch (prot) {
+		case PROT_TYPE_DUMMY:
+			/* We should never get here, acts like termination */
+			WARN_ON_ONCE(1);
+			break;
 		case PROT_TYPE_IEP:
-			tec->b61 = 1;
-			/* FALL THROUGH */
+			teid->b61 = 1;
+			fallthrough;
 		case PROT_TYPE_LA:
-			tec->b56 = 1;
+			teid->b56 = 1;
 			break;
 		case PROT_TYPE_KEYC:
-			tec->b60 = 1;
+			teid->b60 = 1;
 			break;
 		case PROT_TYPE_ALC:
-			tec->b60 = 1;
-			/* FALL THROUGH */
+			teid->b60 = 1;
+			fallthrough;
 		case PROT_TYPE_DAT:
-			tec->b61 = 1;
+			teid->b61 = 1;
 			break;
 		}
-		/* FALL THROUGH */
+		if (terminate) {
+			teid->b56 = 0;
+			teid->b60 = 0;
+			teid->b61 = 0;
+		}
+		fallthrough;
 	case PGM_ASCE_TYPE:
 	case PGM_PAGE_TRANSLATION:
 	case PGM_REGION_FIRST_TRANS:
@@ -531,10 +372,10 @@ static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva,
 		 * 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 */
+		teid->addr = gva >> PAGE_SHIFT;
+		teid->fsi = mode == GACC_STORE ? TEID_FSI_STORE : TEID_FSI_FETCH;
+		teid->as = psw_bits(vcpu->arch.sie_block->gpsw).as;
+		fallthrough;
 	case PGM_ALEN_TRANSLATION:
 	case PGM_ALE_SEQUENCE:
 	case PGM_ASTE_VALIDITY:
@@ -551,6 +392,12 @@ static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva,
 	return code;
 }
 
+static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar,
+		     enum gacc_mode mode, enum prot_type prot)
+{
+	return trans_exc_ending(vcpu, code, gva, ar, mode, prot, false);
+}
+
 static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce,
 			 unsigned long ga, u8 ar, enum gacc_mode mode)
 {
@@ -607,7 +454,7 @@ static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val)
  * 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
+ *	    - a positive value if an access exception happened. In this case
  *	      the returned value is the program interruption code as defined
  *	      by the architecture
  */
@@ -630,7 +477,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 	iep = ctlreg0.iep && test_kvm_facility(vcpu->kvm, 130);
 	if (asce.r)
 		goto real_address;
-	ptr = asce.origin * PAGE_SIZE;
+	ptr = asce.rsto * PAGE_SIZE;
 	switch (asce.dt) {
 	case ASCE_TYPE_REGION1:
 		if (vaddr.rfx01 > asce.tl)
@@ -663,7 +510,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 	case ASCE_TYPE_REGION1:	{
 		union region1_table_entry rfte;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &rfte.val))
 			return -EFAULT;
@@ -677,11 +524,11 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 			dat_protection |= rfte.p;
 		ptr = rfte.rto * PAGE_SIZE + vaddr.rsx * 8;
 	}
-		/* fallthrough */
+		fallthrough;
 	case ASCE_TYPE_REGION2: {
 		union region2_table_entry rste;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &rste.val))
 			return -EFAULT;
@@ -695,11 +542,11 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 			dat_protection |= rste.p;
 		ptr = rste.rto * PAGE_SIZE + vaddr.rtx * 8;
 	}
-		/* fallthrough */
+		fallthrough;
 	case ASCE_TYPE_REGION3: {
 		union region3_table_entry rtte;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &rtte.val))
 			return -EFAULT;
@@ -723,11 +570,11 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 			dat_protection |= rtte.fc0.p;
 		ptr = rtte.fc0.sto * PAGE_SIZE + vaddr.sx * 8;
 	}
-		/* fallthrough */
+		fallthrough;
 	case ASCE_TYPE_SEGMENT: {
 		union segment_table_entry ste;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &ste.val))
 			return -EFAULT;
@@ -747,7 +594,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 		ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8;
 	}
 	}
-	if (kvm_is_error_gpa(vcpu->kvm, ptr))
+	if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 		return PGM_ADDRESSING;
 	if (deref_table(vcpu->kvm, ptr, &pte.val))
 		return -EFAULT;
@@ -769,7 +616,7 @@ absolute_address:
 		*prot = PROT_TYPE_IEP;
 		return PGM_PROTECTION;
 	}
-	if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
+	if (!kvm_is_gpa_in_memslot(vcpu->kvm, raddr.addr))
 		return PGM_ADDRESSING;
 	*gpa = raddr.addr;
 	return 0;
@@ -794,48 +641,272 @@ static int low_address_protection_enabled(struct kvm_vcpu *vcpu,
 	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)
+static int vm_check_access_key(struct kvm *kvm, u8 access_key,
+			       enum gacc_mode mode, gpa_t gpa)
+{
+	u8 storage_key, access_control;
+	bool fetch_protected;
+	unsigned long hva;
+	int r;
+
+	if (access_key == 0)
+		return 0;
+
+	hva = gfn_to_hva(kvm, gpa_to_gfn(gpa));
+	if (kvm_is_error_hva(hva))
+		return PGM_ADDRESSING;
+
+	mmap_read_lock(current->mm);
+	r = get_guest_storage_key(current->mm, hva, &storage_key);
+	mmap_read_unlock(current->mm);
+	if (r)
+		return r;
+	access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key);
+	if (access_control == access_key)
+		return 0;
+	fetch_protected = storage_key & _PAGE_FP_BIT;
+	if ((mode == GACC_FETCH || mode == GACC_IFETCH) && !fetch_protected)
+		return 0;
+	return PGM_PROTECTION;
+}
+
+static bool fetch_prot_override_applicable(struct kvm_vcpu *vcpu, enum gacc_mode mode,
+					   union asce asce)
+{
+	psw_t *psw = &vcpu->arch.sie_block->gpsw;
+	unsigned long override;
+
+	if (mode == GACC_FETCH || mode == GACC_IFETCH) {
+		/* check if fetch protection override enabled */
+		override = vcpu->arch.sie_block->gcr[0];
+		override &= CR0_FETCH_PROTECTION_OVERRIDE;
+		/* not applicable if subject to DAT && private space */
+		override = override && !(psw_bits(*psw).dat && asce.p);
+		return override;
+	}
+	return false;
+}
+
+static bool fetch_prot_override_applies(unsigned long ga, unsigned int len)
+{
+	return ga < 2048 && ga + len <= 2048;
+}
+
+static bool storage_prot_override_applicable(struct kvm_vcpu *vcpu)
+{
+	/* check if storage protection override enabled */
+	return vcpu->arch.sie_block->gcr[0] & CR0_STORAGE_PROTECTION_OVERRIDE;
+}
+
+static bool storage_prot_override_applies(u8 access_control)
+{
+	/* matches special storage protection override key (9) -> allow */
+	return access_control == PAGE_SPO_ACC;
+}
+
+static int vcpu_check_access_key(struct kvm_vcpu *vcpu, u8 access_key,
+				 enum gacc_mode mode, union asce asce, gpa_t gpa,
+				 unsigned long ga, unsigned int len)
+{
+	u8 storage_key, access_control;
+	unsigned long hva;
+	int r;
+
+	/* access key 0 matches any storage key -> allow */
+	if (access_key == 0)
+		return 0;
+	/*
+	 * caller needs to ensure that gfn is accessible, so we can
+	 * assume that this cannot fail
+	 */
+	hva = gfn_to_hva(vcpu->kvm, gpa_to_gfn(gpa));
+	mmap_read_lock(current->mm);
+	r = get_guest_storage_key(current->mm, hva, &storage_key);
+	mmap_read_unlock(current->mm);
+	if (r)
+		return r;
+	access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key);
+	/* access key matches storage key -> allow */
+	if (access_control == access_key)
+		return 0;
+	if (mode == GACC_FETCH || mode == GACC_IFETCH) {
+		/* it is a fetch and fetch protection is off -> allow */
+		if (!(storage_key & _PAGE_FP_BIT))
+			return 0;
+		if (fetch_prot_override_applicable(vcpu, mode, asce) &&
+		    fetch_prot_override_applies(ga, len))
+			return 0;
+	}
+	if (storage_prot_override_applicable(vcpu) &&
+	    storage_prot_override_applies(access_control))
+		return 0;
+	return PGM_PROTECTION;
+}
+
+/**
+ * guest_range_to_gpas() - Calculate guest physical addresses of page fragments
+ * covering a logical range
+ * @vcpu: virtual cpu
+ * @ga: guest address, start of range
+ * @ar: access register
+ * @gpas: output argument, may be NULL
+ * @len: length of range in bytes
+ * @asce: address-space-control element to use for translation
+ * @mode: access mode
+ * @access_key: access key to mach the range's storage keys against
+ *
+ * Translate a logical range to a series of guest absolute addresses,
+ * such that the concatenation of page fragments starting at each gpa make up
+ * the whole range.
+ * The translation is performed as if done by the cpu for the given @asce, @ar,
+ * @mode and state of the @vcpu.
+ * If the translation causes an exception, its program interruption code is
+ * returned and the &struct kvm_s390_pgm_info pgm member of @vcpu is modified
+ * such that a subsequent call to kvm_s390_inject_prog_vcpu() will inject
+ * a correct exception into the guest.
+ * The resulting gpas are stored into @gpas, unless it is NULL.
+ *
+ * Note: All fragments except the first one start at the beginning of a page.
+ *	 When deriving the boundaries of a fragment from a gpa, all but the last
+ *	 fragment end at the end of the page.
+ *
+ * Return:
+ * * 0		- success
+ * * <0		- translation could not be performed, for example if  guest
+ *		  memory could not be accessed
+ * * >0		- an access exception occurred. In this case the returned value
+ *		  is the program interruption code and the contents of pgm may
+ *		  be used to inject an exception into the guest.
+ */
+static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
+			       unsigned long *gpas, unsigned long len,
+			       const union asce asce, enum gacc_mode mode,
+			       u8 access_key)
 {
 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
+	unsigned int offset = offset_in_page(ga);
+	unsigned int fragment_len;
 	int lap_enabled, rc = 0;
 	enum prot_type prot;
+	unsigned long gpa;
 
 	lap_enabled = low_address_protection_enabled(vcpu, asce);
-	while (nr_pages) {
+	while (min(PAGE_SIZE - offset, len) > 0) {
+		fragment_len = min(PAGE_SIZE - offset, len);
 		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);
+			rc = guest_translate(vcpu, ga, &gpa, 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))
+			gpa = kvm_s390_real_to_abs(vcpu, ga);
+			if (!kvm_is_gpa_in_memslot(vcpu->kvm, gpa)) {
 				rc = PGM_ADDRESSING;
+				prot = PROT_TYPE_DUMMY;
+			}
 		}
 		if (rc)
 			return trans_exc(vcpu, rc, ga, ar, mode, prot);
-		ga += PAGE_SIZE;
-		pages++;
-		nr_pages--;
+		rc = vcpu_check_access_key(vcpu, access_key, mode, asce, gpa, ga,
+					   fragment_len);
+		if (rc)
+			return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_KEYC);
+		if (gpas)
+			*gpas++ = gpa;
+		offset = 0;
+		ga += fragment_len;
+		len -= fragment_len;
+	}
+	return 0;
+}
+
+static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,
+			     void *data, unsigned int len)
+{
+	const unsigned int offset = offset_in_page(gpa);
+	const gfn_t gfn = gpa_to_gfn(gpa);
+	int rc;
+
+	if (!gfn_to_memslot(kvm, gfn))
+		return PGM_ADDRESSING;
+	if (mode == GACC_STORE)
+		rc = kvm_write_guest_page(kvm, gfn, data, offset, len);
+	else
+		rc = kvm_read_guest_page(kvm, gfn, data, offset, len);
+	return rc;
+}
+
+static int
+access_guest_page_with_key(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,
+			   void *data, unsigned int len, u8 access_key)
+{
+	struct kvm_memory_slot *slot;
+	bool writable;
+	gfn_t gfn;
+	hva_t hva;
+	int rc;
+
+	gfn = gpa >> PAGE_SHIFT;
+	slot = gfn_to_memslot(kvm, gfn);
+	hva = gfn_to_hva_memslot_prot(slot, gfn, &writable);
+
+	if (kvm_is_error_hva(hva))
+		return PGM_ADDRESSING;
+	/*
+	 * Check if it's a ro memslot, even tho that can't occur (they're unsupported).
+	 * Don't try to actually handle that case.
+	 */
+	if (!writable && mode == GACC_STORE)
+		return -EOPNOTSUPP;
+	hva += offset_in_page(gpa);
+	if (mode == GACC_STORE)
+		rc = copy_to_user_key((void __user *)hva, data, len, access_key);
+	else
+		rc = copy_from_user_key(data, (void __user *)hva, len, access_key);
+	if (rc)
+		return PGM_PROTECTION;
+	if (mode == GACC_STORE)
+		mark_page_dirty_in_slot(kvm, slot, gfn);
+	return 0;
+}
+
+int access_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, void *data,
+			      unsigned long len, enum gacc_mode mode, u8 access_key)
+{
+	int offset = offset_in_page(gpa);
+	int fragment_len;
+	int rc;
+
+	while (min(PAGE_SIZE - offset, len) > 0) {
+		fragment_len = min(PAGE_SIZE - offset, len);
+		rc = access_guest_page_with_key(kvm, mode, gpa, data, fragment_len, access_key);
+		if (rc)
+			return rc;
+		offset = 0;
+		len -= fragment_len;
+		data += fragment_len;
+		gpa += fragment_len;
 	}
 	return 0;
 }
 
-int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
-		 unsigned long len, enum gacc_mode mode)
+int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
+			  void *data, unsigned long len, enum gacc_mode mode,
+			  u8 access_key)
 {
 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
-	unsigned long _len, nr_pages, gpa, idx;
-	unsigned long pages_array[2];
-	unsigned long *pages;
+	unsigned long nr_pages, idx;
+	unsigned long gpa_array[2];
+	unsigned int fragment_len;
+	unsigned long *gpas;
+	enum prot_type prot;
 	int need_ipte_lock;
 	union asce asce;
+	bool try_storage_prot_override;
+	bool try_fetch_prot_override;
 	int rc;
 
 	if (!len)
@@ -845,55 +916,201 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
 	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)
+	gpas = gpa_array;
+	if (nr_pages > ARRAY_SIZE(gpa_array))
+		gpas = vmalloc(array_size(nr_pages, sizeof(unsigned long)));
+	if (!gpas)
 		return -ENOMEM;
+	try_fetch_prot_override = fetch_prot_override_applicable(vcpu, mode, asce);
+	try_storage_prot_override = storage_prot_override_applicable(vcpu);
 	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);
+		ipte_lock(vcpu->kvm);
+	/*
+	 * Since we do the access further down ultimately via a move instruction
+	 * that does key checking and returns an error in case of a protection
+	 * violation, we don't need to do the check during address translation.
+	 * Skip it by passing access key 0, which matches any storage key,
+	 * obviating the need for any further checks. As a result the check is
+	 * handled entirely in hardware on access, we only need to take care to
+	 * forego key protection checking if fetch protection override applies or
+	 * retry with the special key 9 in case of storage protection override.
+	 */
+	rc = guest_range_to_gpas(vcpu, ga, ar, gpas, len, asce, mode, 0);
+	if (rc)
+		goto out_unlock;
+	for (idx = 0; idx < nr_pages; idx++) {
+		fragment_len = min(PAGE_SIZE - offset_in_page(gpas[idx]), len);
+		if (try_fetch_prot_override && fetch_prot_override_applies(ga, fragment_len)) {
+			rc = access_guest_page(vcpu->kvm, mode, gpas[idx],
+					       data, fragment_len);
+		} else {
+			rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx],
+							data, fragment_len, access_key);
+		}
+		if (rc == PGM_PROTECTION && try_storage_prot_override)
+			rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx],
+							data, fragment_len, PAGE_SPO_ACC);
+		if (rc)
+			break;
+		len -= fragment_len;
+		data += fragment_len;
+		ga = kvm_s390_logical_to_effective(vcpu, ga + fragment_len);
+	}
+	if (rc > 0) {
+		bool terminate = (mode == GACC_STORE) && (idx > 0);
+
+		if (rc == PGM_PROTECTION)
+			prot = PROT_TYPE_KEYC;
 		else
-			rc = kvm_read_guest(vcpu->kvm, gpa, data, _len);
-		len -= _len;
-		ga += _len;
-		data += _len;
+			prot = PROT_TYPE_DUMMY;
+		rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate);
 	}
+out_unlock:
 	if (need_ipte_lock)
-		ipte_unlock(vcpu);
-	if (nr_pages > ARRAY_SIZE(pages_array))
-		vfree(pages);
+		ipte_unlock(vcpu->kvm);
+	if (nr_pages > ARRAY_SIZE(gpa_array))
+		vfree(gpas);
 	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;
+	unsigned int fragment_len;
+	unsigned long 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;
+		fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len);
+		rc = access_guest_page(vcpu->kvm, mode, gpa, data, fragment_len);
+		len -= fragment_len;
+		gra += fragment_len;
+		data += fragment_len;
 	}
+	if (rc > 0)
+		vcpu->arch.pgm.code = rc;
 	return rc;
 }
 
 /**
- * guest_translate_address - translate guest logical into guest absolute address
+ * cmpxchg_guest_abs_with_key() - Perform cmpxchg on guest absolute address.
+ * @kvm: Virtual machine instance.
+ * @gpa: Absolute guest address of the location to be changed.
+ * @len: Operand length of the cmpxchg, required: 1 <= len <= 16. Providing a
+ *       non power of two will result in failure.
+ * @old_addr: Pointer to old value. If the location at @gpa contains this value,
+ *            the exchange will succeed. After calling cmpxchg_guest_abs_with_key()
+ *            *@old_addr contains the value at @gpa before the attempt to
+ *            exchange the value.
+ * @new: The value to place at @gpa.
+ * @access_key: The access key to use for the guest access.
+ * @success: output value indicating if an exchange occurred.
+ *
+ * Atomically exchange the value at @gpa by @new, if it contains *@old.
+ * Honors storage keys.
+ *
+ * Return: * 0: successful exchange
+ *         * >0: a program interruption code indicating the reason cmpxchg could
+ *               not be attempted
+ *         * -EINVAL: address misaligned or len not power of two
+ *         * -EAGAIN: transient failure (len 1 or 2)
+ *         * -EOPNOTSUPP: read-only memslot (should never occur)
+ */
+int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len,
+			       __uint128_t *old_addr, __uint128_t new,
+			       u8 access_key, bool *success)
+{
+	gfn_t gfn = gpa_to_gfn(gpa);
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+	bool writable;
+	hva_t hva;
+	int ret;
+
+	if (!IS_ALIGNED(gpa, len))
+		return -EINVAL;
+
+	hva = gfn_to_hva_memslot_prot(slot, gfn, &writable);
+	if (kvm_is_error_hva(hva))
+		return PGM_ADDRESSING;
+	/*
+	 * Check if it's a read-only memslot, even though that cannot occur
+	 * since those are unsupported.
+	 * Don't try to actually handle that case.
+	 */
+	if (!writable)
+		return -EOPNOTSUPP;
+
+	hva += offset_in_page(gpa);
+	/*
+	 * The cmpxchg_user_key macro depends on the type of "old", so we need
+	 * a case for each valid length and get some code duplication as long
+	 * as we don't introduce a new macro.
+	 */
+	switch (len) {
+	case 1: {
+		u8 old;
+
+		ret = cmpxchg_user_key((u8 __user *)hva, &old, *old_addr, new, access_key);
+		*success = !ret && old == *old_addr;
+		*old_addr = old;
+		break;
+	}
+	case 2: {
+		u16 old;
+
+		ret = cmpxchg_user_key((u16 __user *)hva, &old, *old_addr, new, access_key);
+		*success = !ret && old == *old_addr;
+		*old_addr = old;
+		break;
+	}
+	case 4: {
+		u32 old;
+
+		ret = cmpxchg_user_key((u32 __user *)hva, &old, *old_addr, new, access_key);
+		*success = !ret && old == *old_addr;
+		*old_addr = old;
+		break;
+	}
+	case 8: {
+		u64 old;
+
+		ret = cmpxchg_user_key((u64 __user *)hva, &old, *old_addr, new, access_key);
+		*success = !ret && old == *old_addr;
+		*old_addr = old;
+		break;
+	}
+	case 16: {
+		__uint128_t old;
+
+		ret = cmpxchg_user_key((__uint128_t __user *)hva, &old, *old_addr, new, access_key);
+		*success = !ret && old == *old_addr;
+		*old_addr = old;
+		break;
+	}
+	default:
+		return -EINVAL;
+	}
+	if (*success)
+		mark_page_dirty_in_slot(kvm, slot, gfn);
+	/*
+	 * Assume that the fault is caused by protection, either key protection
+	 * or user page write protection.
+	 */
+	if (ret == -EFAULT)
+		ret = PGM_PROTECTION;
+	return ret;
+}
+
+/**
+ * guest_translate_address_with_key - translate guest logical into guest absolute address
+ * @vcpu: virtual cpu
+ * @gva: Guest virtual address
+ * @ar: Access register
+ * @gpa: Guest physical address
+ * @mode: Translation access mode
+ * @access_key: access key to mach the storage key with
  *
  * Parameter semantics are the same as the ones from guest_translate.
  * The memory contents at the guest address are not changed.
@@ -901,11 +1118,10 @@ int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
  * 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)
+int guest_translate_address_with_key(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
+				     unsigned long *gpa, enum gacc_mode mode,
+				     u8 access_key)
 {
-	psw_t *psw = &vcpu->arch.sie_block->gpsw;
-	enum prot_type prot;
 	union asce asce;
 	int rc;
 
@@ -913,49 +1129,62 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
 	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);
-	}
+	return guest_range_to_gpas(vcpu, gva, ar, gpa, 1, asce, mode,
+				   access_key);
+}
 
-	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);
-	}
+/**
+ * check_gva_range - test a range of guest virtual addresses for accessibility
+ * @vcpu: virtual cpu
+ * @gva: Guest virtual address
+ * @ar: Access register
+ * @length: Length of test range
+ * @mode: Translation access mode
+ * @access_key: access key to mach the storage keys with
+ */
+int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
+		    unsigned long length, enum gacc_mode mode, u8 access_key)
+{
+	union asce asce;
+	int rc = 0;
+
+	rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
+	if (rc)
+		return rc;
+	ipte_lock(vcpu->kvm);
+	rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode,
+				 access_key);
+	ipte_unlock(vcpu->kvm);
 
 	return rc;
 }
 
 /**
- * check_gva_range - test a range of guest virtual addresses for accessibility
+ * check_gpa_range - test a range of guest physical addresses for accessibility
+ * @kvm: virtual machine instance
+ * @gpa: guest physical address
+ * @length: length of test range
+ * @mode: access mode to test, relevant for storage keys
+ * @access_key: access key to mach the storage keys with
  */
-int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
-		    unsigned long length, enum gacc_mode mode)
+int check_gpa_range(struct kvm *kvm, unsigned long gpa, unsigned long length,
+		    enum gacc_mode mode, u8 access_key)
 {
-	unsigned long gpa;
-	unsigned long currlen;
+	unsigned int fragment_len;
 	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;
+	while (length && !rc) {
+		fragment_len = min(PAGE_SIZE - offset_in_page(gpa), length);
+		rc = vm_check_access_key(kvm, access_key, mode, gpa);
+		length -= fragment_len;
+		gpa += fragment_len;
 	}
-	ipte_unlock(vcpu);
-
 	return rc;
 }
 
 /**
  * kvm_s390_check_low_addr_prot_real - check for low-address protection
+ * @vcpu: virtual cpu
  * @gra: Guest real address
  *
  * Checks whether an address is subject to low-address protection and set
@@ -976,13 +1205,17 @@ int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra)
  * 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
+ * @pgt: pointer to the beginning of the page table for the given address if
+ *	 successful (return value 0), or to the first invalid DAT entry in
+ *	 case of exceptions (return value > 0)
+ * @dat_protection: referenced memory is write protected
  * @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 kvm *kvm;
 	struct gmap *parent;
 	union asce asce;
 	union vaddress vaddr;
@@ -991,10 +1224,11 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
 
 	*fake = 0;
 	*dat_protection = 0;
+	kvm = sg->private;
 	parent = sg->parent;
 	vaddr.addr = saddr;
 	asce.val = sg->orig_asce;
-	ptr = asce.origin * PAGE_SIZE;
+	ptr = asce.rsto * PAGE_SIZE;
 	if (asce.r) {
 		*fake = 1;
 		ptr = 0;
@@ -1034,6 +1268,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
 			rfte.val = ptr;
 			goto shadow_r2t;
 		}
+		*pgt = ptr + vaddr.rfx * 8;
 		rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val);
 		if (rc)
 			return rc;
@@ -1050,7 +1285,9 @@ shadow_r2t:
 		rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake);
 		if (rc)
 			return rc;
-	} /* fallthrough */
+		kvm->stat.gmap_shadow_r1_entry++;
+	}
+		fallthrough;
 	case ASCE_TYPE_REGION2: {
 		union region2_table_entry rste;
 
@@ -1059,6 +1296,7 @@ shadow_r2t:
 			rste.val = ptr;
 			goto shadow_r3t;
 		}
+		*pgt = ptr + vaddr.rsx * 8;
 		rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val);
 		if (rc)
 			return rc;
@@ -1076,7 +1314,9 @@ shadow_r3t:
 		rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake);
 		if (rc)
 			return rc;
-	} /* fallthrough */
+		kvm->stat.gmap_shadow_r2_entry++;
+	}
+		fallthrough;
 	case ASCE_TYPE_REGION3: {
 		union region3_table_entry rtte;
 
@@ -1085,6 +1325,7 @@ shadow_r3t:
 			rtte.val = ptr;
 			goto shadow_sgt;
 		}
+		*pgt = ptr + vaddr.rtx * 8;
 		rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val);
 		if (rc)
 			return rc;
@@ -1111,7 +1352,9 @@ shadow_sgt:
 		rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake);
 		if (rc)
 			return rc;
-	} /* fallthrough */
+		kvm->stat.gmap_shadow_r3_entry++;
+	}
+		fallthrough;
 	case ASCE_TYPE_SEGMENT: {
 		union segment_table_entry ste;
 
@@ -1120,6 +1363,7 @@ shadow_sgt:
 			ste.val = ptr;
 			goto shadow_pgt;
 		}
+		*pgt = ptr + vaddr.sx * 8;
 		rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val);
 		if (rc)
 			return rc;
@@ -1142,6 +1386,7 @@ shadow_pgt:
 		rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake);
 		if (rc)
 			return rc;
+		kvm->stat.gmap_shadow_sg_entry++;
 	}
 	}
 	/* Return the parent address of the page table */
@@ -1150,10 +1395,50 @@ shadow_pgt:
 }
 
 /**
+ * shadow_pgt_lookup() - find a shadow page table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: the address in the shadow aguest address space
+ * @pgt: parent gmap address of the page table to get shadowed
+ * @dat_protection: if the pgtable is marked as protected by dat
+ * @fake: pgt references contiguous guest memory block, not a pgtable
+ *
+ * Returns 0 if the shadow page table was found and -EAGAIN if the page
+ * table was not found.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+static int shadow_pgt_lookup(struct gmap *sg, unsigned long saddr, unsigned long *pgt,
+			     int *dat_protection, int *fake)
+{
+	unsigned long pt_index;
+	unsigned long *table;
+	struct page *page;
+	int rc;
+
+	spin_lock(&sg->guest_table_lock);
+	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
+	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
+		/* Shadow page tables are full pages (pte+pgste) */
+		page = pfn_to_page(*table >> PAGE_SHIFT);
+		pt_index = gmap_pgste_get_pgt_addr(page_to_virt(page));
+		*pgt = pt_index & ~GMAP_SHADOW_FAKE_TABLE;
+		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
+		*fake = !!(pt_index & GMAP_SHADOW_FAKE_TABLE);
+		rc = 0;
+	} else  {
+		rc = -EAGAIN;
+	}
+	spin_unlock(&sg->guest_table_lock);
+	return rc;
+}
+
+/**
  * 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
+ * @datptr: will contain the address of the faulting DAT table entry, or of
+ *	    the valid leaf, plus some flags
  *
  * Returns: - 0 if the shadow fault was successfully resolved
  *	    - > 0 (pgm exception code) on exceptions while faulting
@@ -1162,23 +1447,26 @@ shadow_pgt:
  *	    - -ENOMEM if out of memory
  */
 int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
-			  unsigned long saddr)
+			  unsigned long saddr, unsigned long *datptr)
 {
 	union vaddress vaddr;
 	union page_table_entry pte;
-	unsigned long pgt;
+	unsigned long pgt = 0;
 	int dat_protection, fake;
 	int rc;
 
-	down_read(&sg->mm->mmap_sem);
+	if (KVM_BUG_ON(!gmap_is_shadow(sg), vcpu->kvm))
+		return -EFAULT;
+
+	mmap_read_lock(sg->mm);
 	/*
 	 * 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);
+	ipte_lock(vcpu->kvm);
 
-	rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
+	rc = shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
 	if (rc)
 		rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection,
 					    &fake);
@@ -1188,8 +1476,20 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
 		pte.val = pgt + vaddr.px * PAGE_SIZE;
 		goto shadow_page;
 	}
-	if (!rc)
-		rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val);
+
+	switch (rc) {
+	case PGM_SEGMENT_TRANSLATION:
+	case PGM_REGION_THIRD_TRANS:
+	case PGM_REGION_SECOND_TRANS:
+	case PGM_REGION_FIRST_TRANS:
+		pgt |= PEI_NOT_PTE;
+		break;
+	case 0:
+		pgt += vaddr.px * 8;
+		rc = gmap_read_table(sg->parent, pgt, &pte.val);
+	}
+	if (datptr)
+		*datptr = pgt | dat_protection * PEI_DAT_PROT;
 	if (!rc && pte.i)
 		rc = PGM_PAGE_TRANSLATION;
 	if (!rc && pte.z)
@@ -1198,7 +1498,8 @@ 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);
+	vcpu->kvm->stat.gmap_shadow_pg_entry++;
+	ipte_unlock(vcpu->kvm);
+	mmap_read_unlock(sg->mm);
 	return rc;
 }