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s390/mm: set and get guest storage key mmap locking

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Move the mmap semaphore locking out of set_guest_storage_key
and get_guest_storage_key. This makes the two functions more
like the other ptep_xxx operations and allows to avoid repeated
semaphore operations if multiple keys are read or written.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2016-03-08 11:53:35 +01:00 committed by Christian Borntraeger
parent c427c42cd6
commit d3ed1ceeac
3 changed files with 24 additions and 24 deletions
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26
arch/s390/kvm/kvm-s390.c
View File

@ -1050,26 +1050,30 @@ static long kvm_s390_get_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
if (!keys)
return -ENOMEM;
down_read(&current->mm->mmap_sem);
for (i = 0; i < args->count; i++) {
hva = gfn_to_hva(kvm, args->start_gfn + i);
if (kvm_is_error_hva(hva)) {
r = -EFAULT;
goto out;
break;
}
curkey = get_guest_storage_key(current->mm, hva);
if (IS_ERR_VALUE(curkey)) {
r = curkey;
goto out;
break;
}
keys[i] = curkey;
}
up_read(&current->mm->mmap_sem);
if (!r) {
r = copy_to_user((uint8_t __user *)args->skeydata_addr, keys,
sizeof(uint8_t) * args->count);
if (r)
r = -EFAULT;
}
r = copy_to_user((uint8_t __user *)args->skeydata_addr, keys,
sizeof(uint8_t) * args->count);
if (r)
r = -EFAULT;
out:
kvfree(keys);
return r;
}
@ -1106,24 +1110,26 @@ static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
if (r)
goto out;
down_read(&current->mm->mmap_sem);
for (i = 0; i < args->count; i++) {
hva = gfn_to_hva(kvm, args->start_gfn + i);
if (kvm_is_error_hva(hva)) {
r = -EFAULT;
goto out;
break;
}
/* Lowest order bit is reserved */
if (keys[i] & 0x01) {
r = -EINVAL;
goto out;
break;
}
r = set_guest_storage_key(current->mm, hva,
(unsigned long)keys[i], 0);
if (r)
goto out;
break;
}
up_read(&current->mm->mmap_sem);
out:
kvfree(keys);
return r;

7
arch/s390/kvm/priv.c
View File

@ -728,9 +728,12 @@ static int handle_pfmf(struct kvm_vcpu *vcpu)
if (rc)
return rc;
if (set_guest_storage_key(current->mm, useraddr,
down_read(&current->mm->mmap_sem);
rc = set_guest_storage_key(current->mm, useraddr,
vcpu->run->s.regs.gprs[reg1] & PFMF_KEY,
vcpu->run->s.regs.gprs[reg1] & PFMF_NQ))
vcpu->run->s.regs.gprs[reg1] & PFMF_NQ);
up_read(&current->mm->mmap_sem);
if (rc)
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
}

15
arch/s390/mm/pgtable.c
View File

@ -506,12 +506,9 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
pgste_t old, new;
pte_t *ptep;
down_read(&mm->mmap_sem);
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep)) {
up_read(&mm->mmap_sem);
if (unlikely(!ptep))
return -EFAULT;
}
new = old = pgste_get_lock(ptep);
pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
@ -538,7 +535,6 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
up_read(&mm->mmap_sem);
return 0;
}
EXPORT_SYMBOL(set_guest_storage_key);
@ -550,14 +546,11 @@ unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr)
pgste_t pgste;
pte_t *ptep;
down_read(&mm->mmap_sem);
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep)) {
up_read(&mm->mmap_sem);
if (unlikely(!ptep))
return -EFAULT;
}
pgste = pgste_get_lock(ptep);
pgste = pgste_get_lock(ptep);
if (pte_val(*ptep) & _PAGE_INVALID) {
key = (pgste_val(pgste) & PGSTE_ACC_BITS) >> 56;
key |= (pgste_val(pgste) & PGSTE_FP_BIT) >> 56;
@ -572,10 +565,8 @@ unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr)
if (pgste_val(pgste) & PGSTE_GC_BIT)
key |= _PAGE_CHANGED;
}
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
up_read(&mm->mmap_sem);
return key;
}
EXPORT_SYMBOL(get_guest_storage_key);