diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kvm/priv.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 391626361084..d02638959922 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -336,6 +336,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu) u64 address1 = disp1 + base1 ? vcpu->arch.guest_gprs[base1] : 0; u64 address2 = disp2 + base2 ? vcpu->arch.guest_gprs[base2] : 0; struct vm_area_struct *vma; + unsigned long user_address; vcpu->stat.instruction_tprot++; @@ -349,9 +350,14 @@ static int handle_tprot(struct kvm_vcpu *vcpu) 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(¤t->mm->mmap_sem); - vma = find_vma(current->mm, - (unsigned long) __guestaddr_to_user(vcpu, address1)); + vma = find_vma(current->mm, user_address); if (!vma) { up_read(¤t->mm->mmap_sem); return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); |