KVM: s390: Enable DAT support for TPROT handler

The TPROT instruction can be used to check the accessability of storage
for any kind of logical addresses. So far, our handler only supported
real addresses. This patch now also enables support for addresses that
have to be translated via DAT first. And while we're at it, change the
code to use the common KVM function gfn_to_hva_prot() to check for the
validity and writability of the memory page.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

1 files changed, 33 insertions, 23 deletions

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 6296159ac883..f89c1cd67751 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -930,8 +930,9 @@ int kvm_s390_handle_eb(struct kvm_vcpu *vcpu)
 static int handle_tprot(struct kvm_vcpu *vcpu)
 {
 	u64 address1, address2;
-	struct vm_area_struct *vma;
-	unsigned long user_address;
+	unsigned long hva, gpa;
+	int ret = 0, cc = 0;
+	bool writable;
 
 	vcpu->stat.instruction_tprot++;
 
@@ -942,32 +943,41 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
 
 	/* we only handle the Linux memory detection case:
 	 * access key == 0
-	 * guest DAT == off
 	 * everything else goes to userspace. */
 	if (address2 & 0xf0)
 		return -EOPNOTSUPP;
 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
-		return -EOPNOTSUPP;
-
-	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)
-		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);
-	if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
-		vcpu->arch.sie_block->gpsw.mask |= (2ul << 44);
-
-	up_read(&current->mm->mmap_sem);
-	return 0;
+		ipte_lock(vcpu);
+	ret = guest_translate_address(vcpu, address1, &gpa, 1);
+	if (ret == PGM_PROTECTION) {
+		/* Write protected? Try again with read-only... */
+		cc = 1;
+		ret = guest_translate_address(vcpu, address1, &gpa, 0);
+	}
+	if (ret) {
+		if (ret == PGM_ADDRESSING || ret == PGM_TRANSLATION_SPEC) {
+			ret = kvm_s390_inject_program_int(vcpu, ret);
+		} else if (ret > 0) {
+			/* Translation not available */
+			kvm_s390_set_psw_cc(vcpu, 3);
+			ret = 0;
+		}
+		goto out_unlock;
+	}
 
-out_inject:
-	up_read(&current->mm->mmap_sem);
-	return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+	hva = gfn_to_hva_prot(vcpu->kvm, gpa_to_gfn(gpa), &writable);
+	if (kvm_is_error_hva(hva)) {
+		ret = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+	} else {
+		if (!writable)
+			cc = 1;		/* Write not permitted ==> read-only */
+		kvm_s390_set_psw_cc(vcpu, cc);
+		/* Note: CC2 only occurs for storage keys (not supported yet) */
+	}
+out_unlock:
+	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
+		ipte_unlock(vcpu);
+	return ret;
 }
 
 int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)