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linux/arch/s390/kvm/gaccess.c

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// 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 <linux/pgtable.h>
#include <linux/bitfield.h>
#include <linux/kvm_host.h>
#include <linux/kvm_types.h>
#include <asm/diag.h>
#include <asm/access-regs.h>
#include <asm/fault.h>
#include <asm/dat-bits.h>
#include "kvm-s390.h"
#include "dat.h"
#include "gmap.h"
#include "gaccess.h"
#include "faultin.h"
#define GMAP_SHADOW_FAKE_TABLE 1ULL
union dat_table_entry {
unsigned long val;
union region1_table_entry pgd;
union region2_table_entry p4d;
union region3_table_entry pud;
union segment_table_entry pmd;
union page_table_entry pte;
};
#define WALK_N_ENTRIES 7
#define LEVEL_MEM -2
struct pgtwalk {
struct guest_fault raw_entries[WALK_N_ENTRIES];
gpa_t last_addr;
int level;
bool p;
};
static inline struct guest_fault *get_entries(struct pgtwalk *w)
{
return w->raw_entries - LEVEL_MEM;
}
/*
* 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 */
};
union oac {
unsigned int val;
struct {
struct {
unsigned short key : 4;
unsigned short : 4;
unsigned short as : 2;
unsigned short : 4;
unsigned short k : 1;
unsigned short a : 1;
} oac1;
struct {
unsigned short key : 4;
unsigned short : 4;
unsigned short as : 2;
unsigned short : 4;
unsigned short k : 1;
unsigned short a : 1;
} oac2;
};
};
int ipte_lock_held(struct kvm *kvm)
{
if (sclp.has_siif)
return kvm->arch.sca->ipte_control.kh != 0;
return kvm->arch.ipte_lock_count != 0;
}
static void ipte_lock_simple(struct kvm *kvm)
{
union ipte_control old, new, *ic;
mutex_lock(&kvm->arch.ipte_mutex);
kvm->arch.ipte_lock_count++;
if (kvm->arch.ipte_lock_count > 1)
goto out;
retry:
ic = &kvm->arch.sca->ipte_control;
old = READ_ONCE(*ic);
do {
if (old.k) {
cond_resched();
goto retry;
}
new = old;
new.k = 1;
} while (!try_cmpxchg(&ic->val, &old.val, new.val));
out:
mutex_unlock(&kvm->arch.ipte_mutex);
}
static void ipte_unlock_simple(struct kvm *kvm)
{
union ipte_control old, new, *ic;
mutex_lock(&kvm->arch.ipte_mutex);
kvm->arch.ipte_lock_count--;
if (kvm->arch.ipte_lock_count)
goto out;
ic = &kvm->arch.sca->ipte_control;
old = READ_ONCE(*ic);
do {
new = old;
new.k = 0;
} while (!try_cmpxchg(&ic->val, &old.val, new.val));
wake_up(&kvm->arch.ipte_wq);
out:
mutex_unlock(&kvm->arch.ipte_mutex);
}
static void ipte_lock_siif(struct kvm *kvm)
{
union ipte_control old, new, *ic;
retry:
ic = &kvm->arch.sca->ipte_control;
old = READ_ONCE(*ic);
do {
if (old.kg) {
cond_resched();
goto retry;
}
new = old;
new.k = 1;
new.kh++;
} while (!try_cmpxchg(&ic->val, &old.val, new.val));
}
static void ipte_unlock_siif(struct kvm *kvm)
{
union ipte_control old, new, *ic;
ic = &kvm->arch.sca->ipte_control;
old = READ_ONCE(*ic);
do {
new = old;
new.kh--;
if (!new.kh)
new.k = 0;
} while (!try_cmpxchg(&ic->val, &old.val, new.val));
if (!new.kh)
wake_up(&kvm->arch.ipte_wq);
}
void ipte_lock(struct kvm *kvm)
{
if (sclp.has_siif)
ipte_lock_siif(kvm);
else
ipte_lock_simple(kvm);
}
void ipte_unlock(struct kvm *kvm)
{
if (sclp.has_siif)
ipte_unlock_siif(kvm);
else
ipte_unlock_simple(kvm);
}
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;
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) {
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;
}
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_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;
union teid *teid;
memset(pgm, 0, sizeof(*pgm));
pgm->code = 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:
teid->b61 = 1;
fallthrough;
case PROT_TYPE_LA:
teid->b56 = 1;
break;
case PROT_TYPE_KEYC:
teid->b60 = 1;
break;
case PROT_TYPE_ALC:
teid->b60 = 1;
fallthrough;
case PROT_TYPE_DAT:
teid->b61 = 1;
break;
}
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:
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.
*/
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:
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 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)
{
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_gva() - 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 positive 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_gva(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.rsto * 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_gpa_in_memslot(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_gpa_in_memslot(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_gpa_in_memslot(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_gpa_in_memslot(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_gpa_in_memslot(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_gpa_in_memslot(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 vm_check_access_key_gpa(struct kvm *kvm, u8 access_key,
enum gacc_mode mode, gpa_t gpa)
{
union skey storage_key;
int r;
scoped_guard(read_lock, &kvm->mmu_lock)
r = dat_get_storage_key(kvm->arch.gmap->asce, gpa_to_gfn(gpa), &storage_key);
if (r)
return r;
if (access_key == 0 || storage_key.acc == access_key)
return 0;
if ((mode == GACC_FETCH || mode == GACC_IFETCH) && !storage_key.fp)
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_gpa(struct kvm_vcpu *vcpu, u8 access_key,
enum gacc_mode mode, union asce asce, gpa_t gpa,
unsigned long ga, unsigned int len)
{
union skey storage_key;
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
*/
scoped_guard(read_lock, &vcpu->kvm->mmu_lock)
r = dat_get_storage_key(vcpu->arch.gmap->asce, gpa_to_gfn(gpa), &storage_key);
if (r)
return r;
/* access key matches storage key -> allow */
if (storage_key.acc == access_key)
return 0;
if (mode == GACC_FETCH || mode == GACC_IFETCH) {
/* it is a fetch and fetch protection is off -> allow */
if (!storage_key.fp)
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(storage_key.acc))
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 (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);
if (psw_bits(*psw).dat) {
rc = guest_translate_gva(vcpu, ga, &gpa, asce, mode, &prot);
if (rc < 0)
return rc;
} else {
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);
rc = vcpu_check_access_key_gpa(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_gpa(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 mvcos_key(void *to, const void *from, unsigned long size, u8 dst_key, u8 src_key)
{
union oac spec = {
.oac1.key = dst_key,
.oac1.k = !!dst_key,
.oac2.key = src_key,
.oac2.k = !!src_key,
};
int exception = PGM_PROTECTION;
asm_inline volatile(
" lr %%r0,%[spec]\n"
"0: mvcos %[to],%[from],%[size]\n"
"1: lhi %[exc],0\n"
"2:\n"
EX_TABLE(0b, 2b)
EX_TABLE(1b, 2b)
: [size] "+d" (size), [to] "=Q" (*(char *)to), [exc] "+d" (exception)
: [spec] "d" (spec.val), [from] "Q" (*(const char *)from)
: "memory", "cc", "0");
return exception;
}
struct acc_page_key_context {
void *data;
int exception;
unsigned short offset;
unsigned short len;
bool store;
u8 access_key;
};
static void _access_guest_page_with_key_gpa(struct guest_fault *f)
{
struct acc_page_key_context *context = f->priv;
void *ptr;
int r;
ptr = __va(PFN_PHYS(f->pfn) | context->offset);
if (context->store)
r = mvcos_key(ptr, context->data, context->len, context->access_key, 0);
else
r = mvcos_key(context->data, ptr, context->len, 0, context->access_key);
context->exception = r;
}
static int access_guest_page_with_key_gpa(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,
void *data, unsigned int len, u8 acc)
{
struct acc_page_key_context context = {
.offset = offset_in_page(gpa),
.len = len,
.data = data,
.access_key = acc,
.store = mode == GACC_STORE,
};
struct guest_fault fault = {
.gfn = gpa_to_gfn(gpa),
.priv = &context,
.write_attempt = mode == GACC_STORE,
.callback = _access_guest_page_with_key_gpa,
};
int rc;
if (KVM_BUG_ON((len + context.offset) > PAGE_SIZE, kvm))
return -EINVAL;
rc = kvm_s390_faultin_gfn(NULL, kvm, &fault);
if (rc)
return rc;
return context.exception;
}
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_gpa(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_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 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)
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;
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->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_gpa(vcpu->kvm, mode, gpas[idx], data, fragment_len);
} else {
rc = access_guest_page_with_key_gpa(vcpu->kvm, mode, gpas[idx],
data, fragment_len, access_key);
}
if (rc == PGM_PROTECTION && try_storage_prot_override)
rc = access_guest_page_with_key_gpa(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
prot = PROT_TYPE_DUMMY;
rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate);
}
out_unlock:
if (need_ipte_lock)
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 int fragment_len;
unsigned long gpa;
int rc = 0;
while (len && !rc) {
gpa = kvm_s390_real_to_abs(vcpu, gra);
fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len);
rc = access_guest_page_gpa(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;
}
/**
* __cmpxchg_with_key() - Perform cmpxchg, honoring storage keys.
* @ptr: Address of value to compare to *@old and exchange with
* @new. Must be aligned to @size.
* @old: Old value. Compared to the content pointed to by @ptr in order to
* determine if the exchange occurs. The old value read from *@ptr is
* written here.
* @new: New value to place at *@ptr.
* @size: Size of the operation in bytes, may only be a power of two up to 16.
* @access_key: Access key to use for checking storage key protection.
*
* Perform a cmpxchg on guest memory, honoring storage key protection.
* @access_key alone determines how key checking is performed, neither
* storage-protection-override nor fetch-protection-override apply.
* In case of an exception *@uval is set to zero.
*
* Return:
* * %0: cmpxchg executed successfully
* * %1: cmpxchg executed unsuccessfully
* * %PGM_PROTECTION: an exception happened when trying to access *@ptr
* * %-EAGAIN: maxed out number of retries (byte and short only)
* * %-EINVAL: invalid value for @size
*/
static int __cmpxchg_with_key(union kvm_s390_quad *ptr, union kvm_s390_quad *old,
union kvm_s390_quad new, int size, u8 access_key)
{
union kvm_s390_quad tmp = { .sixteen = 0 };
int rc;
/*
* The cmpxchg_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 (size) {
case 1:
rc = __cmpxchg_key1(&ptr->one, &tmp.one, old->one, new.one, access_key);
break;
case 2:
rc = __cmpxchg_key2(&ptr->two, &tmp.two, old->two, new.two, access_key);
break;
case 4:
rc = __cmpxchg_key4(&ptr->four, &tmp.four, old->four, new.four, access_key);
break;
case 8:
rc = __cmpxchg_key8(&ptr->eight, &tmp.eight, old->eight, new.eight, access_key);
break;
case 16:
rc = __cmpxchg_key16(&ptr->sixteen, &tmp.sixteen, old->sixteen, new.sixteen,
access_key);
break;
default:
return -EINVAL;
}
if (!rc && memcmp(&tmp, old, size))
rc = 1;
*old = tmp;
/*
* Assume that the fault is caused by protection, either key protection
* or user page write protection.
*/
if (rc == -EFAULT)
rc = PGM_PROTECTION;
return rc;
}
struct cmpxchg_key_context {
union kvm_s390_quad new;
union kvm_s390_quad *old;
int exception;
unsigned short offset;
u8 access_key;
u8 len;
};
static void _cmpxchg_guest_abs_with_key(struct guest_fault *f)
{
struct cmpxchg_key_context *context = f->priv;
context->exception = __cmpxchg_with_key(__va(PFN_PHYS(f->pfn) | context->offset),
context->old, context->new, context->len,
context->access_key);
}
/**
* 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: Pointer to old value. If the location at @gpa contains this value,
* the exchange will succeed. After calling cmpxchg_guest_abs_with_key()
* *@old contains the value at @gpa before the attempt to
* exchange the value.
* @new: The value to place at @gpa.
* @acc: 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, union kvm_s390_quad *old,
union kvm_s390_quad new, u8 acc, bool *success)
{
struct cmpxchg_key_context context = {
.old = old,
.new = new,
.offset = offset_in_page(gpa),
.len = len,
.access_key = acc,
};
struct guest_fault fault = {
.gfn = gpa_to_gfn(gpa),
.priv = &context,
.write_attempt = true,
.callback = _cmpxchg_guest_abs_with_key,
};
int rc;
lockdep_assert_held(&kvm->srcu);
if (len > 16 || !IS_ALIGNED(gpa, len))
return -EINVAL;
rc = kvm_s390_faultin_gfn(NULL, kvm, &fault);
if (rc)
return rc;
*success = !context.exception;
if (context.exception == 1)
return 0;
return context.exception;
}
/**
* 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.
*
* Note: The IPTE lock is not taken during this function, so the caller
* has to take care of this.
*/
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)
{
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;
return guest_range_to_gpas(vcpu, gva, ar, gpa, 1, asce, mode,
access_key);
}
/**
* 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_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_gpa_range(struct kvm *kvm, unsigned long gpa, unsigned long length,
enum gacc_mode mode, u8 access_key)
{
unsigned int fragment_len;
int rc = 0;
while (length && !rc) {
fragment_len = min(PAGE_SIZE - offset_in_page(gpa), length);
rc = vm_check_access_key_gpa(kvm, access_key, mode, gpa);
length -= fragment_len;
gpa += fragment_len;
}
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
* 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);
}
/**
* walk_guest_tables() - Walk the guest page table and pin the dat tables.
* @sg: Pointer to the shadow guest address space structure.
* @saddr: Faulting address in the shadow gmap.
* @w: Will be filled with information on the pinned pages.
* @wr: Wndicates a write access if true.
*
* Return:
* * %0 in case of success,
* * a PIC code > 0 in case the address translation fails
* * an error code < 0 if other errors happen in the host
*/
static int walk_guest_tables(struct gmap *sg, unsigned long saddr, struct pgtwalk *w, bool wr)
{
struct gmap *parent = sg->parent;
struct guest_fault *entries;
union dat_table_entry table;
union vaddress vaddr;
unsigned long ptr;
struct kvm *kvm;
union asce asce;
int rc;
if (!parent)
return -EAGAIN;
kvm = parent->kvm;
WARN_ON(!kvm);
asce = sg->guest_asce;
entries = get_entries(w);
w->level = LEVEL_MEM;
w->last_addr = saddr;
if (asce.r)
return kvm_s390_get_guest_page(kvm, entries + LEVEL_MEM, gpa_to_gfn(saddr), false);
vaddr.addr = saddr;
ptr = asce.rsto * PAGE_SIZE;
if (!asce_contains_gfn(asce, gpa_to_gfn(saddr)))
return PGM_ASCE_TYPE;
switch (asce.dt) {
case ASCE_TYPE_REGION1:
if (vaddr.rfx01 > asce.tl)
return PGM_REGION_FIRST_TRANS;
break;
case ASCE_TYPE_REGION2:
if (vaddr.rsx01 > asce.tl)
return PGM_REGION_SECOND_TRANS;
break;
case ASCE_TYPE_REGION3:
if (vaddr.rtx01 > asce.tl)
return PGM_REGION_THIRD_TRANS;
break;
case ASCE_TYPE_SEGMENT:
if (vaddr.sx01 > asce.tl)
return PGM_SEGMENT_TRANSLATION;
break;
}
w->level = asce.dt;
switch (asce.dt) {
case ASCE_TYPE_REGION1:
w->last_addr = ptr + vaddr.rfx * 8;
rc = kvm_s390_get_guest_page_and_read_gpa(kvm, entries + w->level,
w->last_addr, &table.val);
if (rc)
return rc;
if (table.pgd.i)
return PGM_REGION_FIRST_TRANS;
if (table.pgd.tt != TABLE_TYPE_REGION1)
return PGM_TRANSLATION_SPEC;
if (vaddr.rsx01 < table.pgd.tf || vaddr.rsx01 > table.pgd.tl)
return PGM_REGION_SECOND_TRANS;
if (sg->edat_level >= 1)
w->p |= table.pgd.p;
ptr = table.pgd.rto * PAGE_SIZE;
w->level--;
fallthrough;
case ASCE_TYPE_REGION2:
w->last_addr = ptr + vaddr.rsx * 8;
rc = kvm_s390_get_guest_page_and_read_gpa(kvm, entries + w->level,
w->last_addr, &table.val);
if (rc)
return rc;
if (table.p4d.i)
return PGM_REGION_SECOND_TRANS;
if (table.p4d.tt != TABLE_TYPE_REGION2)
return PGM_TRANSLATION_SPEC;
if (vaddr.rtx01 < table.p4d.tf || vaddr.rtx01 > table.p4d.tl)
return PGM_REGION_THIRD_TRANS;
if (sg->edat_level >= 1)
w->p |= table.p4d.p;
ptr = table.p4d.rto * PAGE_SIZE;
w->level--;
fallthrough;
case ASCE_TYPE_REGION3:
w->last_addr = ptr + vaddr.rtx * 8;
rc = kvm_s390_get_guest_page_and_read_gpa(kvm, entries + w->level,
w->last_addr, &table.val);
if (rc)
return rc;
if (table.pud.i)
return PGM_REGION_THIRD_TRANS;
if (table.pud.tt != TABLE_TYPE_REGION3)
return PGM_TRANSLATION_SPEC;
if (table.pud.cr && asce.p && sg->edat_level >= 2)
return PGM_TRANSLATION_SPEC;
if (sg->edat_level >= 1)
w->p |= table.pud.p;
if (table.pud.fc && sg->edat_level >= 2) {
table.val = u64_replace_bits(table.val, saddr, ~_REGION3_MASK);
goto edat_applies;
}
if (vaddr.sx01 < table.pud.fc0.tf || vaddr.sx01 > table.pud.fc0.tl)
return PGM_SEGMENT_TRANSLATION;
ptr = table.pud.fc0.sto * PAGE_SIZE;
w->level--;
fallthrough;
case ASCE_TYPE_SEGMENT:
w->last_addr = ptr + vaddr.sx * 8;
rc = kvm_s390_get_guest_page_and_read_gpa(kvm, entries + w->level,
w->last_addr, &table.val);
if (rc)
return rc;
if (table.pmd.i)
return PGM_SEGMENT_TRANSLATION;
if (table.pmd.tt != TABLE_TYPE_SEGMENT)
return PGM_TRANSLATION_SPEC;
if (table.pmd.cs && asce.p)
return PGM_TRANSLATION_SPEC;
w->p |= table.pmd.p;
if (table.pmd.fc && sg->edat_level >= 1) {
table.val = u64_replace_bits(table.val, saddr, ~_SEGMENT_MASK);
goto edat_applies;
}
ptr = table.pmd.fc0.pto * (PAGE_SIZE / 2);
w->level--;
}
w->last_addr = ptr + vaddr.px * 8;
rc = kvm_s390_get_guest_page_and_read_gpa(kvm, entries + w->level,
w->last_addr, &table.val);
if (rc)
return rc;
if (table.pte.i)
return PGM_PAGE_TRANSLATION;
if (table.pte.z)
return PGM_TRANSLATION_SPEC;
w->p |= table.pte.p;
edat_applies:
if (wr && w->p)
return PGM_PROTECTION;
return kvm_s390_get_guest_page(kvm, entries + LEVEL_MEM, table.pte.pfra, wr);
}
static int _do_shadow_pte(struct gmap *sg, gpa_t raddr, union pte *ptep_h, union pte *ptep,
struct guest_fault *f, bool p)
{
union pgste pgste;
union pte newpte;
int rc;
lockdep_assert_held(&sg->kvm->mmu_lock);
lockdep_assert_held(&sg->parent->children_lock);
scoped_guard(spinlock, &sg->host_to_rmap_lock)
rc = gmap_insert_rmap(sg, f->gfn, gpa_to_gfn(raddr), TABLE_TYPE_PAGE_TABLE);
if (rc)
return rc;
if (!pgste_get_trylock(ptep_h, &pgste))
return -EAGAIN;
newpte = _pte(f->pfn, f->writable, !p, ptep_h->s.s);
newpte.s.d |= ptep_h->s.d;
newpte.s.sd |= ptep_h->s.sd;
newpte.h.p &= ptep_h->h.p;
if (!newpte.h.p && !f->writable) {
rc = -EOPNOTSUPP;
} else {
pgste = _gmap_ptep_xchg(sg->parent, ptep_h, newpte, pgste, f->gfn, false);
pgste.vsie_notif = 1;
}
pgste_set_unlock(ptep_h, pgste);
if (rc)
return rc;
if (!sg->parent)
return -EAGAIN;
newpte = _pte(f->pfn, 0, !p, 0);
if (!pgste_get_trylock(ptep, &pgste))
return -EAGAIN;
pgste = __dat_ptep_xchg(ptep, pgste, newpte, gpa_to_gfn(raddr), sg->asce, uses_skeys(sg));
pgste_set_unlock(ptep, pgste);
return 0;
}
static int _do_shadow_crste(struct gmap *sg, gpa_t raddr, union crste *host, union crste *table,
struct guest_fault *f, bool p)
{
union crste newcrste, oldcrste;
gfn_t gfn;
int rc;
lockdep_assert_held(&sg->kvm->mmu_lock);
lockdep_assert_held(&sg->parent->children_lock);
gfn = f->gfn & gpa_to_gfn(is_pmd(*table) ? _SEGMENT_MASK : _REGION3_MASK);
scoped_guard(spinlock, &sg->host_to_rmap_lock)
rc = gmap_insert_rmap(sg, gfn, gpa_to_gfn(raddr), host->h.tt);
if (rc)
return rc;
do {
/* _gmap_crstep_xchg_atomic() could have unshadowed this shadow gmap */
if (!sg->parent)
return -EAGAIN;
oldcrste = READ_ONCE(*host);
newcrste = _crste_fc1(f->pfn, oldcrste.h.tt, f->writable, !p);
newcrste.s.fc1.d |= oldcrste.s.fc1.d;
newcrste.s.fc1.sd |= oldcrste.s.fc1.sd;
newcrste.h.p &= oldcrste.h.p;
newcrste.s.fc1.vsie_notif = 1;
newcrste.s.fc1.prefix_notif = oldcrste.s.fc1.prefix_notif;
newcrste.s.fc1.s = oldcrste.s.fc1.s;
if (!newcrste.h.p && !f->writable)
return -EOPNOTSUPP;
} while (!_gmap_crstep_xchg_atomic(sg->parent, host, oldcrste, newcrste, f->gfn, false));
if (!sg->parent)
return -EAGAIN;
newcrste = _crste_fc1(f->pfn, oldcrste.h.tt, 0, !p);
gfn = gpa_to_gfn(raddr);
while (!dat_crstep_xchg_atomic(table, READ_ONCE(*table), newcrste, gfn, sg->asce))
;
return 0;
}
static int _gaccess_do_shadow(struct kvm_s390_mmu_cache *mc, struct gmap *sg,
unsigned long saddr, struct pgtwalk *w)
{
struct guest_fault *entries;
int flags, i, hl, gl, l, rc;
union crste *table, *host;
union pte *ptep, *ptep_h;
lockdep_assert_held(&sg->kvm->mmu_lock);
lockdep_assert_held(&sg->parent->children_lock);
entries = get_entries(w);
ptep_h = NULL;
ptep = NULL;
rc = dat_entry_walk(NULL, gpa_to_gfn(saddr), sg->asce, DAT_WALK_ANY, TABLE_TYPE_PAGE_TABLE,
&table, &ptep);
if (rc)
return rc;
/* A race occurred. The shadow mapping is already valid, nothing to do */
if ((ptep && !ptep->h.i && ptep->h.p == w->p) ||
(!ptep && crste_leaf(*table) && !table->h.i && table->h.p == w->p))
return 0;
gl = get_level(table, ptep);
/* In case of a real address space */
if (w->level <= LEVEL_MEM) {
l = TABLE_TYPE_PAGE_TABLE;
hl = TABLE_TYPE_REGION1;
goto real_address_space;
}
/*
* Skip levels that are already protected. For each level, protect
* only the page containing the entry, not the whole table.
*/
for (i = gl ; i >= w->level; i--) {
rc = gmap_protect_rmap(mc, sg, entries[i].gfn, gpa_to_gfn(saddr),
entries[i].pfn, i + 1, entries[i].writable);
if (rc)
return rc;
if (!sg->parent)
return -EAGAIN;
}
rc = dat_entry_walk(NULL, entries[LEVEL_MEM].gfn, sg->parent->asce, DAT_WALK_LEAF,
TABLE_TYPE_PAGE_TABLE, &host, &ptep_h);
if (rc)
return rc;
hl = get_level(host, ptep_h);
/* Get the smallest granularity */
l = min3(gl, hl, w->level);
real_address_space:
flags = DAT_WALK_SPLIT_ALLOC | (uses_skeys(sg->parent) ? DAT_WALK_USES_SKEYS : 0);
/* If necessary, create the shadow mapping */
if (l < gl) {
rc = dat_entry_walk(mc, gpa_to_gfn(saddr), sg->asce, flags, l, &table, &ptep);
if (rc)
return rc;
}
if (l < hl) {
rc = dat_entry_walk(mc, entries[LEVEL_MEM].gfn, sg->parent->asce,
flags, l, &host, &ptep_h);
if (rc)
return rc;
}
if (KVM_BUG_ON(l > TABLE_TYPE_REGION3, sg->kvm))
return -EFAULT;
if (l == TABLE_TYPE_PAGE_TABLE)
return _do_shadow_pte(sg, saddr, ptep_h, ptep, entries + LEVEL_MEM, w->p);
return _do_shadow_crste(sg, saddr, host, table, entries + LEVEL_MEM, w->p);
}
static inline int _gaccess_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, gpa_t saddr,
unsigned long seq, struct pgtwalk *walk)
{
struct gmap *parent;
int rc;
if (kvm_s390_array_needs_retry_unsafe(vcpu->kvm, seq, walk->raw_entries))
return -EAGAIN;
again:
rc = kvm_s390_mmu_cache_topup(vcpu->arch.mc);
if (rc)
return rc;
scoped_guard(read_lock, &vcpu->kvm->mmu_lock) {
if (kvm_s390_array_needs_retry_safe(vcpu->kvm, seq, walk->raw_entries))
return -EAGAIN;
parent = READ_ONCE(sg->parent);
if (!parent)
return -EAGAIN;
scoped_guard(spinlock, &parent->children_lock) {
if (READ_ONCE(sg->parent) != parent)
return -EAGAIN;
rc = _gaccess_do_shadow(vcpu->arch.mc, sg, saddr, walk);
}
if (rc == -ENOMEM)
goto again;
if (!rc)
kvm_s390_release_faultin_array(vcpu->kvm, walk->raw_entries, false);
}
return rc;
}
/**
* __gaccess_shadow_fault() - Handle fault on a shadow page table.
* @vcpu: Virtual cpu that triggered the action.
* @sg: 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.
* @wr: Whether this is a write access.
*
* Return:
* * %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
*/
static int __gaccess_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, gpa_t saddr,
union mvpg_pei *datptr, bool wr)
{
struct pgtwalk walk = { .p = false, };
unsigned long seq;
int rc;
seq = vcpu->kvm->mmu_invalidate_seq;
/* Pairs with the smp_wmb() in kvm_mmu_invalidate_end(). */
smp_rmb();
rc = walk_guest_tables(sg, saddr, &walk, wr);
if (datptr) {
datptr->val = walk.last_addr;
datptr->dat_prot = wr && walk.p;
datptr->not_pte = walk.level > TABLE_TYPE_PAGE_TABLE;
datptr->real = sg->guest_asce.r;
}
if (!rc)
rc = _gaccess_shadow_fault(vcpu, sg, saddr, seq, &walk);
if (rc)
kvm_s390_release_faultin_array(vcpu->kvm, walk.raw_entries, true);
return rc;
}
int gaccess_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, gpa_t saddr,
union mvpg_pei *datptr, bool wr)
{
int rc;
if (KVM_BUG_ON(!test_bit(GMAP_FLAG_SHADOW, &sg->flags), vcpu->kvm))
return -EFAULT;
rc = kvm_s390_mmu_cache_topup(vcpu->arch.mc);
if (rc)
return rc;
ipte_lock(vcpu->kvm);
rc = __gaccess_shadow_fault(vcpu, sg, saddr, datptr, wr || sg->guest_asce.r);
ipte_unlock(vcpu->kvm);
return rc;
}
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