s390/kvm,tprot: use new gmap_translate() function

When out-of-memory the tprot code incorrectly injected a program check
for the guest which reported an addressing exception even if the guest
address was valid.
Let's use the new gmap_translate() which translates a guest address to
a user space address whithout the chance of running into an out-of-memory
situation.
Also make it more explicit that for -EFAULT we won't find a vma.

Signed-off-by: Heiko Carstens <heiko.carstens@de.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>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 9 insertions, 12 deletions

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 0ef9894606e5..75ad91e38e8a 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -575,20 +575,13 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
                 return -EOPNOTSUPP;
 
-
-        /* we must resolve the address without holding the mmap semaphore.
-         * This is ok since the userspace hypervisor is not supposed to change
-         * the mapping while the guest queries the memory. Otherwise the guest
-         * might crash or get wrong info anyway. */
-        user_address = (unsigned long) __guestaddr_to_user(vcpu, address1);
-
         down_read(&current->mm->mmap_sem);
+        user_address = __gmap_translate(address1, vcpu->arch.gmap);
+        if (IS_ERR_VALUE(user_address))
+                goto out_inject;
         vma = find_vma(current->mm, user_address);
-        if (!vma) {
-                up_read(&current->mm->mmap_sem);
-                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-        }
-
+        if (!vma)
+                goto out_inject;
         vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
         if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
                 vcpu->arch.sie_block->gpsw.mask |= (1ul << 44);
@@ -597,6 +590,10 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
 
         up_read(&current->mm->mmap_sem);
         return 0;
+
+out_inject:
+        up_read(&current->mm->mmap_sem);
+        return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 }
 
 int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)