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KVM: s390: Cleanup ipte lock access and SIIF facility checks
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We can check if SIIF is enabled by testing the sclp_info struct
instead of testing the sie control block eca variable as that
facility is always enabled if available.

Also let's cleanup all the ipte related struct member accesses
which currently happen by referencing the KVM struct via the
VCPU struct.
Making the KVM struct the parameter to the ipte_* functions
removes one level of indirection which makes the code more readable.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Link: https://lore.kernel.org/all/20220711084148.25017-2-pmorel@linux.ibm.com/
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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Pierre Morel authored and Janosch Frank committed Jul 20, 2022
1 parent c3f0e5f commit 0130337
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Showing 3 changed files with 54 additions and 54 deletions.
96 changes: 48 additions & 48 deletions arch/s390/kvm/gaccess.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -262,119 +262,119 @@ 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);
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);
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);
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);
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);
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);
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);
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);
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,
Expand Down Expand Up @@ -1086,7 +1086,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
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);
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
Expand Down Expand Up @@ -1127,7 +1127,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
}
out_unlock:
if (need_ipte_lock)
ipte_unlock(vcpu);
ipte_unlock(vcpu->kvm);
if (nr_pages > ARRAY_SIZE(gpa_array))
vfree(gpas);
return rc;
Expand Down Expand Up @@ -1199,10 +1199,10 @@ int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
if (rc)
return rc;
ipte_lock(vcpu);
ipte_lock(vcpu->kvm);
rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode,
access_key);
ipte_unlock(vcpu);
ipte_unlock(vcpu->kvm);

return rc;
}
Expand Down Expand Up @@ -1465,7 +1465,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
* 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);
if (rc)
Expand Down Expand Up @@ -1499,7 +1499,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
pte.p |= dat_protection;
if (!rc)
rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
ipte_unlock(vcpu);
ipte_unlock(vcpu->kvm);
mmap_read_unlock(sg->mm);
return rc;
}
6 changes: 3 additions & 3 deletions arch/s390/kvm/gaccess.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -440,9 +440,9 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
return access_guest_real(vcpu, gra, data, len, 0);
}

void ipte_lock(struct kvm_vcpu *vcpu);
void ipte_unlock(struct kvm_vcpu *vcpu);
int ipte_lock_held(struct kvm_vcpu *vcpu);
void ipte_lock(struct kvm *kvm);
void ipte_unlock(struct kvm *kvm);
int ipte_lock_held(struct kvm *kvm);
int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);

/* MVPG PEI indication bits */
Expand Down
6 changes: 3 additions & 3 deletions arch/s390/kvm/priv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -442,7 +442,7 @@ static int handle_ipte_interlock(struct kvm_vcpu *vcpu)
vcpu->stat.instruction_ipte_interlock++;
if (psw_bits(vcpu->arch.sie_block->gpsw).pstate)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu));
wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu->kvm));
kvm_s390_retry_instr(vcpu);
VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation");
return 0;
Expand Down Expand Up @@ -1471,7 +1471,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
access_key = (operand2 & 0xf0) >> 4;

if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
ipte_lock(vcpu);
ipte_lock(vcpu->kvm);

ret = guest_translate_address_with_key(vcpu, address, ar, &gpa,
GACC_STORE, access_key);
Expand Down Expand Up @@ -1508,7 +1508,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
}

if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
ipte_unlock(vcpu);
ipte_unlock(vcpu->kvm);
return ret;
}

Expand Down

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