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60815cf2e0
linux/arch/s390/kvm/gaccess.c
Linus Torvalds 60815cf2e0 kernel: Provide READ_ONCE and ASSIGN_ONCE 
As discussed on LKML http://marc.info/?i=54611D86.4040306%40de.ibm.com
 ACCESS_ONCE might fail with specific compilers for non-scalar accesses.
 
 Here is a set of patches to tackle that problem.
 
 The first patch introduce READ_ONCE and ASSIGN_ONCE. If the data structure
 is larger than the machine word size memcpy is used and a warning is emitted.
 The next patches fix up several in-tree users of ACCESS_ONCE on non-scalar
 types.
 
 This merge does not yet contain a patch that forces ACCESS_ONCE to work only
 on scalar types. This is targetted for the next merge window as Linux next
 already contains new offenders regarding ACCESS_ONCE vs. non-scalar types.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux

Pull ACCESS_ONCE cleanup preparation from Christian Borntraeger:
 "kernel: Provide READ_ONCE and ASSIGN_ONCE

  As discussed on LKML http://marc.info/?i=54611D86.4040306%40de.ibm.com
  ACCESS_ONCE might fail with specific compilers for non-scalar
  accesses.

  Here is a set of patches to tackle that problem.

  The first patch introduce READ_ONCE and ASSIGN_ONCE.  If the data
  structure is larger than the machine word size memcpy is used and a
  warning is emitted.  The next patches fix up several in-tree users of
  ACCESS_ONCE on non-scalar types.

  This does not yet contain a patch that forces ACCESS_ONCE to work only
  on scalar types.  This is targetted for the next merge window as Linux
  next already contains new offenders regarding ACCESS_ONCE vs.
  non-scalar types"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux:
  s390/kvm: REPLACE barrier fixup with READ_ONCE
  arm/spinlock: Replace ACCESS_ONCE with READ_ONCE
  arm64/spinlock: Replace ACCESS_ONCE READ_ONCE
  mips/gup: Replace ACCESS_ONCE with READ_ONCE
  x86/gup: Replace ACCESS_ONCE with READ_ONCE
  x86/spinlock: Replace ACCESS_ONCE with READ_ONCE
  mm: replace ACCESS_ONCE with READ_ONCE or barriers
  kernel: Provide READ_ONCE and ASSIGN_ONCE
2014-12-20 16:48:59 -08:00

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/*
* guest access functions
*
* Copyright IBM Corp. 2014
*
*/
#include <linux/vmalloc.h>
#include <linux/err.h>
#include <asm/pgtable.h>
#include "kvm-s390.h"
#include "gaccess.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 co : 1; /* Change-Recording Override */
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 co : 1; /* Change-Recording Override */
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 co : 1; /* Change-Recording Override */
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 */
};
int ipte_lock_held(struct kvm_vcpu *vcpu)
{
union ipte_control *ic = &vcpu->kvm->arch.sca->ipte_control;
if (vcpu->arch.sie_block->eca & 1)
return ic->kh != 0;
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;
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
old = READ_ONCE(*ic);
while (old.k) {
cond_resched();
old = READ_ONCE(*ic);
}
new = old;
new.k = 1;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
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;
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
old = READ_ONCE(*ic);
new = old;
new.k = 0;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
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;
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
old = READ_ONCE(*ic);
while (old.kg) {
cond_resched();
old = READ_ONCE(*ic);
}
new = old;
new.k = 1;
new.kh++;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
}
static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
{
union ipte_control old, new, *ic;
ic = &vcpu->kvm->arch.sca->ipte_control;
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);
if (!new.kh)
wake_up(&vcpu->kvm->arch.ipte_wq);
}
void ipte_lock(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.sie_block->eca & 1)
ipte_lock_siif(vcpu);
else
ipte_lock_simple(vcpu);
}
void ipte_unlock(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.sie_block->eca & 1)
ipte_unlock_siif(vcpu);
else
ipte_unlock_simple(vcpu);
}
static unsigned long get_vcpu_asce(struct kvm_vcpu *vcpu)
{
switch (psw_bits(vcpu->arch.sie_block->gpsw).as) {
case PSW_AS_PRIMARY:
return vcpu->arch.sie_block->gcr[1];
case PSW_AS_SECONDARY:
return vcpu->arch.sie_block->gcr[7];
case PSW_AS_HOME:
return vcpu->arch.sie_block->gcr[13];
}
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
* @write: indicates if access is a write access
*
* Translate a guest virtual address into a guest absolute address by means
* of dynamic address translation as specified by the architecuture.
* 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, int write)
{
union vaddress vaddr = {.addr = gva};
union raddress raddr = {.addr = gva};
union page_table_entry pte;
int dat_protection = 0;
union ctlreg0 ctlreg0;
unsigned long ptr;
int edat1, edat2;
union asce asce;
ctlreg0.val = vcpu->arch.sie_block->gcr[0];
edat1 = ctlreg0.edat && test_vfacility(8);
edat2 = edat1 && test_vfacility(78);
asce.val = get_vcpu_asce(vcpu);
if (asce.r)
goto real_address;
ptr = asce.origin * 4096;
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 * 4096 + 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 * 4096 + 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;
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 * 4096 + 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;
raddr.sfaa = ste.fc1.sfaa;
goto absolute_address;
}
dat_protection |= ste.fc0.p;
ptr = ste.fc0.pto * 2048 + 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;
if (pte.co && !edat1)
return PGM_TRANSLATION_SPEC;
dat_protection |= pte.p;
raddr.pfra = pte.pfra;
real_address:
raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
absolute_address:
if (write && dat_protection)
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)
{
union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
psw_t *psw = &vcpu->arch.sie_block->gpsw;
union asce asce;
if (!ctlreg0.lap)
return 0;
asce.val = get_vcpu_asce(vcpu);
if (psw_bits(*psw).t && asce.p)
return 0;
return 1;
}
struct trans_exc_code_bits {
unsigned long addr : 52; /* Translation-exception Address */
unsigned long fsi : 2; /* Access Exception Fetch/Store Indication */
unsigned long : 7;
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 */
};
static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga,
unsigned long *pages, unsigned long nr_pages,
int write)
{
struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
psw_t *psw = &vcpu->arch.sie_block->gpsw;
struct trans_exc_code_bits *tec_bits;
int lap_enabled, rc;
memset(pgm, 0, sizeof(*pgm));
tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
tec_bits->fsi = write ? FSI_STORE : FSI_FETCH;
tec_bits->as = psw_bits(*psw).as;
lap_enabled = low_address_protection_enabled(vcpu);
while (nr_pages) {
ga = kvm_s390_logical_to_effective(vcpu, ga);
tec_bits->addr = ga >> PAGE_SHIFT;
if (write && lap_enabled && is_low_address(ga)) {
pgm->code = PGM_PROTECTION;
return pgm->code;
}
ga &= PAGE_MASK;
if (psw_bits(*psw).t) {
rc = guest_translate(vcpu, ga, pages, write);
if (rc < 0)
return rc;
if (rc == PGM_PROTECTION)
tec_bits->b61 = 1;
if (rc)
pgm->code = rc;
} else {
*pages = kvm_s390_real_to_abs(vcpu, ga);
if (kvm_is_error_gpa(vcpu->kvm, *pages))
pgm->code = PGM_ADDRESSING;
}
if (pgm->code)
return pgm->code;
ga += PAGE_SIZE;
pages++;
nr_pages--;
}
return 0;
}
int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
unsigned long len, int write)
{
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;
/* Access register mode is not supported yet. */
if (psw_bits(*psw).t && psw_bits(*psw).as == PSW_AS_ACCREG)
return -EOPNOTSUPP;
nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1;
pages = pages_array;
if (nr_pages > ARRAY_SIZE(pages_array))
pages = vmalloc(nr_pages * sizeof(unsigned long));
if (!pages)
return -ENOMEM;
asce.val = get_vcpu_asce(vcpu);
need_ipte_lock = psw_bits(*psw).t && !asce.r;
if (need_ipte_lock)
ipte_lock(vcpu);
rc = guest_page_range(vcpu, ga, pages, nr_pages, write);
for (idx = 0; idx < nr_pages && !rc; idx++) {
gpa = *(pages + idx) + (ga & ~PAGE_MASK);
_len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
if (write)
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, int write)
{
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 (write)
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,
unsigned long *gpa, int write)
{
struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
psw_t *psw = &vcpu->arch.sie_block->gpsw;
struct trans_exc_code_bits *tec;
union asce asce;
int rc;
/* Access register mode is not supported yet. */
if (psw_bits(*psw).t && psw_bits(*psw).as == PSW_AS_ACCREG)
return -EOPNOTSUPP;
gva = kvm_s390_logical_to_effective(vcpu, gva);
memset(pgm, 0, sizeof(*pgm));
tec = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
tec->as = psw_bits(*psw).as;
tec->fsi = write ? FSI_STORE : FSI_FETCH;
tec->addr = gva >> PAGE_SHIFT;
if (is_low_address(gva) && low_address_protection_enabled(vcpu)) {
if (write) {
rc = pgm->code = PGM_PROTECTION;
return rc;
}
}
asce.val = get_vcpu_asce(vcpu);
if (psw_bits(*psw).t && !asce.r) { /* Use DAT? */
rc = guest_translate(vcpu, gva, gpa, write);
if (rc > 0) {
if (rc == PGM_PROTECTION)
tec->b61 = 1;
pgm->code = rc;
}
} else {
rc = 0;
*gpa = kvm_s390_real_to_abs(vcpu, gva);
if (kvm_is_error_gpa(vcpu->kvm, *gpa))
rc = pgm->code = PGM_ADDRESSING;
}
return rc;
}
/**
* kvm_s390_check_low_addr_protection - check for low-address protection
* @ga: Guest 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_protection(struct kvm_vcpu *vcpu, unsigned long ga)
{
struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
psw_t *psw = &vcpu->arch.sie_block->gpsw;
struct trans_exc_code_bits *tec_bits;
if (!is_low_address(ga) || !low_address_protection_enabled(vcpu))
return 0;
memset(pgm, 0, sizeof(*pgm));
tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
tec_bits->fsi = FSI_STORE;
tec_bits->as = psw_bits(*psw).as;
tec_bits->addr = ga >> PAGE_SHIFT;
pgm->code = PGM_PROTECTION;
return pgm->code;
}
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